BACKGROUND OF THE INVENTION

Arylomycin and its synthetic analogues, that exhibit potent activity against gram-negative bacteria, belong to the family of biaryl-bridged cyclic peptides. Some members of this family, including for example arylomicin A (compound 2), G0775 (compound 3) and RP 66453 (compound 4), are shown in Figure 1A.

The biosynthesis of biaryl-bridged cyclic peptides involves a metalloenzyme-catalyzed oxidative coupling step between two phenol-based amino acid residues, such as tyrosine (Tyr) and 4- hydroxyphenyl glycine (Hpg). However, mimicking this reactivity in the laboratory is not straightforward, due to the low reactivity of Tyr and Hpg in oxidative coupling reactions.

The commonly used synthetic method to form biaryl compounds, such as for example, compounds 1-5 in Figure 1A, relies on palladium-catalyzed cross-coupling between two activated arene fragments. However, a series of functional group interconversion steps are needed before and after the biaryl bond forming step to ensure selectivity, thus making the process lengthy and producing significant amounts of by-products.

Recently, the groups of Baran and Romesberg took a biomimetic approach to assembling biaryl- bridged cyclic peptide 7 by developing a metal oxidative macrocyclization of the N-Boc-N-Me-L- Hpg-L-Ala-L-Tyr-OMe tripeptide 6 (Figure 1 B) (Peters, D. S. et al., Scalable access to arylomycins via C-H functionalization logic. J. Am. Chem. Soc. 2018, 140 (6), 2072-2075). In their methodology, two equivalents of a copper amine oxidant, which had been prepared from a freshly crystallized Cu[MeCN] ₄ [PF ₆ ] complex and A/,/V,/\/,/\/-tetramethylethylenediamine (TMEDA) under an 0 ₂ atmosphere, afforded the desired arylomycin cyclic core 7 in an approximately 60% yield. However, the product was contaminated with a substantial amount of an inseparable inorganic salt NaPF ₆ (ca. 50% w/w), moreover, no attempt was made to show the generality of the reaction for the preparation of analogs.

Using a different approach, the Romesberg group prepared the arylomycin cyclic core 7 in fourteen (14) synthetic steps via a key Suzuki reaction step (Lim, N.-K. et al., Macrolactamization Approaches to Arylomycin Antibiotics Core. Org. Lett. 2018; Liu, J. et al., Synthesis and characterization of the arylomycin lipoglycopeptide antibiotics and the crystallographic analysis of their complex with signal peptidase. J. Am. Chem. Soc. 2011, 133 (44), 17869-17877).

The total syntheses of other bioactive di-tyrosine-containing macrocyclic peptides, such as RP 66453 (compound 4) and mycocyclosin (compound 5), have also been achieved using various cross-coupling strategies (Feliu, L. and Planas, M., Cyclic peptides containing biaryl and biaryl ether linkages. Int J. Pept. Res. Therapeut. 2005, 11 (1), 53-97; Carbonnelle, A.-C. and Zhu, J., A Novel Synthesis of Biaryl-Containing Macrocycles by a Domino Miyaura Arylboronate Formation: Intramolecular Suzuki Reaction. Org. Lett. 2000, 2 (22), 3477-3480; Zhu, X. et al., Scalable Synthesis of Mycocyclosin. Org. Lett. 2018, 20 (10), 2862-2866; Cochrane, J. R. et al., Total Synthesis of Mycocyclosin. Org. Lett. 2012, 14 (9), 2402-2405; Moschitto, M. J. and Lewis, C. A., Synthesis of the Rubiyunnanin B Core Aglycon. Eur. J. Org. Chem. 2016, 2016 (28), 4773- 4777; Krenitsky, P. J. and Boger, D. L., Synthesis of the (S,S,S)-diastereomer of the 15- membered biaryl ring system of RP 66453. Tetrahedron Lett. 2003, 44 (21), 4019-4022; Bois- Choussy, M. et al., Total Synthesis of an Atropdiastereomer of RP-66453 and Determination of Its Absolute Configuration. Angew. Chem. Int. Ed. 2003, 42 (35), 4238-4241 ; Boisnard, S. et al., Studies on the Total Synthesis of RP 66453: Synthesis of Fully Functionalized 15-Membered Biaryl-Containing Macrocycle. Org. Lett. 2001 , 3 (13), 2061-2064). Yet, as in the arylomycin case, these laborious multi-step syntheses do not offer the synthetic flexibility that is needed for drug development and commercialization.

Therefore, there is a need to provide an alternative synthetic route for the manufacture of biaryl- bridged cyclic peptides in a simple and efficient manner.

SUMMARY OF THE INVENTION

Surprisingly, it has now been found that biaryl-bridged cyclic peptides, such as, without being limited to, arylomycin A (compound 2), G0775 (compound 3) and RP 66453 (compound 4), in particular compounds comprising the macrocyclic core of Formula (I):

Formula (I) wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ⁱ⁰ , R ¹¹ , R ¹² , n and m are as defined hereinafter, are obtainable in high diasiereomeric and enantiomeric purity and in an economic manner using tyrosine (Tyr) residues activated by a labile activating group (AG) and / or using novel 4- hydroxyphenylg!ycine (Hpg) residues activated by a labile activating group (AG)

Therefore in a first aspect, the present invention provides a method of preparing a biaryl-bridged cyclic peptide compound of Formula (I)

Formula (I) wherein:

R ¹ and R ⁵ eacb independently is hydrogen, Ci- alkyl, or amino-Ci. ₄ alkyl, wherein each amino moiety may optionally include a protecting group; R ² , R ³ , R ⁴ , R ⁶ , R ⁷ and R ⁸ each independently is hydrogen, Ci- ₄ aikyl, halo, amino, hydroxyl, hydroxy-Ci- ₄ alkyl, cyano or nitro; wherein each amino moiety and each hydroxy! moiety may optionally include a protecting group;

R ⁹ and R ¹⁰ each independently is hydrogen, Ci. ₄ alkyi, amino acid residue or a peptide residue; wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ¹¹ is hydrogen, Ci- ₄ alkyl, aryiaikyi, halo-Ci. ₄ alkyl, halo, amino, amino-Ci- ₄ alkyl, hydroxyl, hydroxy-Ci. ₆ alkyl, hydroxy-arylalkyl, cyano, or cyano-C . aikyl; or R ¹¹ together with the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five- or six- membered ring; and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ¹² is hydroxyl, amino, Ci. ₄ alkoxy, or -NH-Y; wherein Y is carboxy-C .. ₅ alkyl· cyano-Ci. ₄ alkyl, or arylcarboxyCi- ₅ a!kyl; or Y together with the nitrogen atom to which it is attached may form a five- or six- membered heterocyclic ring, and wherein each amino moiety and each hydroxyl moiety may optionally Include a protecting group; and n and m each independently is 0 or 1 ; the method comprising: reacting a compound of Formula A: Formula A or a salt or solvate thereof, with a compound of Formula B:

Formula B or a salt or solvate thereof, wherein:

AG is a labile activating group; and may be the same or different on each occurrence;

Pg ¹ is an optional amine protecting group;

Pg ² is hydrogen, C _h alky!, or hydroxyl protecting group;

-L ¹ -C(0)- may be absent or present, and if present L ¹ is --amino-, -amino-Ci-saiky!-, or -C -sheterocyc!ic amine--, wherein L ¹ is optionally substituted with one or more of hydroxy-Ci- _S aikyl--, orhydroxyl-aryl-Ci- ₆ alkyl-, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

Pg ³ is an optional amine protecting group;

-L ² - may be absent or present, and if present L ² is:

wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , n and m are as defined for a compound of Formula (I), in the presence of a catalyst and an oxidant, to form a compound of Formula C or a salt or solvate thereof; wherein:

AG is a labile activating group; and may be the same or different on each occurrence;

R ¹ , R ³ , R ⁴ , R ¹⁰ , L ¹ , Pg ¹ , Pg ² and n are as defined for a compound of Formula A; and wherein R ⁵ , R ⁷ , R ⁸ , R ^{1 !} , R ¹² , L ² , Pg ³ and m are as defined for a compound of Formula B; subjecting the compound of Formula C or a salt or solvate thereof to macrolactamization to prepare the compound of Formula D

Formula D or a salt or solvate thereof; wherein:

AG is a labile activating group; and may be the same or different on each occurrence;

R\ R ³ , R ⁴ , R ¹⁰ , Pg ¹ and n are as defined for a compound of Formula A; and wherein

R ⁵ , R ⁷ , R ⁸ , R ¹¹ , R ¹² and m are as defined for a compound of Formula B; and removing the activating and protecting groups to make the compound of Formula (I); or a pharmaceutically acceptable salt or solvate thereof.

As an alternative approach to obtain the compound of the Formula (I), the present invention relates in another aspect to a method for preparing a compound of Formula (I)

Formula (I) wherein

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , n and m are as defined hereinbefore; the method comprising: subjecting to an amidation (amide coupling) reaction a compound of Formula A Formula A or a salt or solvate thereof; and a compound of Formula B

Formula B or a salt or solvate thereof; wherein:

AG is a labile activating group; and may be the same or different on each occurrence;

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ⁹ , R ^1C , R ¹¹ , R ¹² , Pg ¹ , Pg ² , Pg ³ , L ¹ , L ² , n and m are as defined hereinbefore; to form a compound of Formula E

Formula E or a salt or solvate thereof; wherein: AG is a labile activating group; and may be the same or different on each occurrence;

R\ R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , Pg ¹ , n and m are as defined hereinbefore; treating the compound of Formula E with a metal oxidant having the general Formula F:

[Cu"(OH) .TMEDA] ₂ [X] ₂ Formula F wherein

X is trifluoromethane sulfonate (TfO), methane sulfonate (MsO), or perchlorate (C!0 ₄ ); to make the compound of Formula D

Formula D or a salt or solvate thereof; wherein:

AG is a labile activating group; and may be the same or different on each occurrence;

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , Pg ¹ , n and m are as defined hereinbefore; and removing the activating and protecting groups to make the compound of Formula (I); or a pharmaceutically acceptable salt or solvate thereof.

The subject methods provide a short, reliable and flexible method for synthesizing biaryl-bridged cyclic peptides of Formula (I). The biary!-bridged cyclic peptides of Formula (I) may be used in the preparation of pharmaceutically active substances, such as, for example, aryiomycin and arylomycin analogues. Thus, for example, the biary!-bridged cyclic peptides of Formula (I) may be used in preparation of arylomycin A (compound 2), G0775 (compound 3) and RP66453 (compound 4).

Additional aspects of the invention, embodiments and details are provided below.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1A shows some members of the arylomycin family of biaryl-bridged cyclic peptides, including for example arylomicin A (compound 2), G0775 (compound 3) and RP 66453 (compound 4), are shown in Figure 1A.

Figure 1 B shows the biomimetic approach to assembling of biaryl-bridged cyclic peptide 7 by developing a metal oxidative macrocyclization of the A/-Boc-/\/-Me-L-Hpg-L-Ala-L-Tyr-OMe tripeptide 6, as undertaken by the groups of Baran and Romesberg.

Figure 2A demonstrates a representative HPLC Chromatogram of Entry 4 in Table S2. Table S2 provides the results of oxidative coupling of Cbz-L-(2-f-Bu)Tyr-OMe (compound 9b) under different conditions.

Figure 2B demonstrates a representative cyclic voltammetry of compound 8b and compound 9b in CH ₃ CN (3 mM) with iefrabutyiammonium hexafluorophosphate (TBAP) as the supporting electrolyte (50 mM) vs Ag/Q.01 M AgNQ ₃ in 0.1 M TBAP/CH ₃ CN, scan rate = 50 mV s-1.

Figure 2C HPLC demonstrates representative chromatograms for the oxidative homocoupling of tyrosine compound 8b (1) or activated tyrosine compound 9b (2) by Fe[TPP]CI (1 mol %) and UHP (2 equiv) in HFIP at room temperature. Figure 3 demonstrates a representative products distribution for oxidative coupling of N-Boc-N- Me-L-(2-f-Bu)Hpg-OBn (compound 12) and A/-Cbz-L-Ala-L-(2-f-Bu)Tyr-OMe (compound 13) as was monitored by HPLC. Conditions: A) compound 13 (1 equiv), compound 12 (1 equiv), Fe[TPP]CI (1 mol %), UHP (1.2 equiv), HFIP, 1 h; B) compound 13 (1 equiv), compound 12 (1 equiv), Fe[TPP]CI (1 mol %), m-CPBA (1.5 equiv), HFIP, 1 h; C) compound 13 (1 equiv), compound 12 (1 equiv), Fe[TPP]CI (1 mol %), rn-CPBA (1.5 equiv), DCE, 1 h; D) dropwise addition of compound 13 (1 equiv), compound 12 (3 equiv), Fe[TPP]CI (1 mol %), rn-CPBA (1.5 equiv), DCE, 2h.

Figure 4 demonstrates a representative cyclic voltammetry of compound 12 and compound 13 in DCE (3 m ) with ietrabuty!ammonium hexaf!uorophosphate (TBAP) as the supporting electrolyte (50 mM) vs Ag/0.01 M AgNC ₃ in 0.1 M TBAP/CH ₃ CN, scan rate = 50 mV s-1.

Figure 5 demonstrates a representative ¹ H-NMR spectrum of A) Fe[TPP][compound12] compound 12A B) Fe[TPP][ compound 13] compound 13A C) a mixture of Fe[TPP][ compound 12] compound 12A and Fe[TPP][ compound 13] compound 13A D) a mixture Fe[TPP][ compound 12] compound 12A, Fe[TPP][ compound 13] compound 13A and Fe[TPP][HFIP] Abbreviations: /7?-Ph = Phenyl H _mefa of Tetraphenyl porphyrin, Pyr-H = pyrrole-H.

Figure 6 demonstrates a representative products distribution for the oxidative coupling of /V-Boc- L-(2-f-Bu)Tyr-L-Tyr-OBn (compound 33) and A/-Cbz-L-(2-f-Bu)Tyr-OMe (compound 9b). Conditions: compound 33 (1 equiv), compound 9b (1 equiv), Fe[TPP]CI (1 mol %), UHP (1.2 equiv), HFIP, 20 min.

Figure 7 demonstrates a representative HPLC Chromatogram for oxidative coupling of compound 17 by complexes 19 and 20 (i.e. compound 19 and compound 20).

Figure 8 demonstrates a representative characterization of compound 20 using XRD.

DETAILED DESCRIPTION OF THE INVENTION

Scheme 1A provides a general schematic representation of Approach A to synthesis of biaryl- cyclic peptides. This approach forms the first aspect of the invention.

Scheme 1A

In Scheme 1A wavy lines correspond to the R groups defined for Formulae A, B, C, D and (I) hereinbefore and hereinafter. in the first step of Scheme 1A, each of Tyr and/ or Hpg residues that are utilized as the staring materials in the synthesis undergo activation by installation of an activating group (AG), at the ortho- position of the phenolic moiety. Exemplary activating groups include bulky alkyl groups, such as, for example, fert-butyl (f-Bu), dimefhy!pheny! (dmp) and triphenyi (trityi). In many embodiments the activation group is a fe/f-butyl group. The installation of an activating group (AG) may be carried out using reagents such as tert-Butyl chloride (t-BuCI), tert-Buty! alcohol (t- BuOH), (chloromethanetriyl)tribenzene (trityi chloride), triphenylmeihanol (Ph ₃ COH), 2- Phenyipropan-2-ol, and (2-chloropropan-2-yl)benzene, in acid such as, for example, methanesulfonic acid or sulfuric acid, in a temperature range of about 20-7Q°C. in many embodiments a least one of the Tyr and/ or Hpg residues used in step 1 is a short peptide, preferably dipeptide or tripeptide, formed by linking Tyr or Hpg with one or more amino acids via amide bond.

An amine and / or hydroxyl protecting group may be introduced after the installation of AG, to provide amine-protected activated Tyr and/ or Hpg residue. In many embodiments the amine protecting groups are selected from a carboxybenzyl (Cbz) group, such as for example benzyl chloroformate (CbzCi), and a tert-butoxycarbonyl (Boo) group, such as for example di-tert-butyl dicarbonate (Boc20). The introduction of protecting group may be achieved using a base such as, for example sodium hydroxide (NaOH) or triethyiamine (Et ₃ N), in a protic solvent such as, for example methanol (MeOH), or a solvent mixture such as, for example Tetrahydrofuran-water (THF/HzO). The resulting activated, and optionally protected, Tyr and/ or Hpg residues are identified herein as compounds of general Formula A and of general Formula B

In step 2, the two discrete activated phenol-based amino acids are subjected to oxidative coupling to afford a biaryl-bridged linear peptide identified herein as compound of general Formula C. Prior to the oxidative coupling reaction, the oxidation potential of each activated phenol-based amino acid may be determined, in order to establish the optimal mole ratio that will enhance cross- coupling selectivity and result in high yield of the desired coupling product. The oxidation potential may be determined for example by using cyclic voltammetry conditions, such as for example using tetrabutylammonium hexafluorophosphate (TBAP) as the supporting electrolyte (50 mM) vs Ag/0.01 M AgNG3 in 0.1 M TBAP/CH3CN, scan rate = 50 mV s-1 in CH3CN or DCE. The oxidative coupling may be carried out under mild metal-catalyzed conditions, such as for example using mefa-chloroperbenzoic acid (50 - 200 moi%) or urea hydrogen peroxide (UHP) (50 - 500 mo!%) and Fe[TPP]CI (0 01 - 100 mol %), in a solvent, preferably an inert organic solvent, for example 1 ,2-dichloroethane or 1,1,1,3,3,3-hexafluoropropan~2~ol, at a room temperature for 15 - 30 minutes. Other catalysts useful in the oxidative coupling reaction are FeC , [Cu"(OH) «TMEDA] ₂ [CI] ₂ , and Cofsalen]. Upon completion of the reaction (as indicated for example by HPLC analysis), the solvent may be removed, for example under reduced pressure. The resulting residue may be purified, for example, by using column chromatography.

Macrocyclization is carried out in step 3 to afford the novel biaryi-bridged compounds having the general Formula D. In many embodiments the macrocyclization may be achieved by first combining the biaryi-bridged linear peptide product of step 2 with a catalyst, such as a palladium catalyst, such as palladium on carbon (e.g. Pd-G/H ₂ ), in a solvent, such as methanol, or other lower alcohol, then filtration of the catalyst and removal of the solvent. In the next step, the resulting residue may be added to a mixture of a coupling reagent, such as, for example, (benzotriazol-l-yloxy)tripyrrolidinophosphonium hexafluorophosphate (PyBOP) and a catalyst, such as, for example, 4-(N,N-dimethylamino)pyridine (DMAP), in a polar aprotic solvent, such as acetonitrile. in the final step, the AG and the protecting groups are removed, thereby affording the target biaryl- cyclic peptide of general Formula (I) in pure form (>95% purity according to HPLC and NMR methods). In certain embodiments, removal of protecting groups prior to the removal of AG may be required to prevent undesired side reactions. For example, the removal of N-carbamate protecting groups may be carried out using, for example, 2,2,2-trifluoroacetic acid (TFA) in dichloromethane (DCM) or using, for example, Pd-C/H ₂ in methanol. Removal of activating groups may be carried out, for example, by Friedel-Crafts dealkylation, using triflic acid (TfOH) or perchloric acid (CIO.H) in HFIP.

Scheme 1 B provides a general schematic representation of Approach B, an alternative approach to synthesis of biaryi-cyc!ic peptides. This approach forms another aspect of the invention.

Scheme 1 B

In Scheme 1B wavy lines correspond to the R groups defined for Formulae A, B, E, D and (I) hereinbefore and hereinafter.

In the first step of Scheme 1 B, AG installation and, optionally, protecting group introduction is carried out as described above for the first step of Scheme 1 A. The resulting activated Tyr and/ or Hpg residues are identified herein as compounds of general Formula A and of general Formula B. in step 2, the two discrete activated phenol-based amino acid compounds (of Formula A and Formula B) are subjected to amidation coupling reaction to afford a linear peptide identified herein as compounds having the general Formula E. The amidation may be carried out using a coupling reagent such as, for example, 1-Ethyl-3-(3-dimethylaminopropyi)carbodiimide (EDC) in combination with 1-Hydroxybenzotriazole (HOBT), or N,N'-Dicyclobexyicarbodiimide (DCC) in combination with 1-Hydroxybenzoiriazole (HOBT); and a base such as, for example triethyiamine (Ei3N), in aprotic solvent such as, for example dimethylformamide (DMF) or acetonitrile, in a temperature range of 20 - 80 °C Oxidative macrocyclization (a ring formation) of the linear peptide product of step 2 is carried out in step 3 to afford the novel biaryl-bridged compounds having the general Formula D.

The oxidative macrocyclization is carried out using a novel metal oxidant having the general Formula [Cu"(OH) «TMEDA] ₂ [X]2 (Formula F) (100 mo!%), with X representing a group such as trifluoromethane sulfonate (TfO) (compound 20), methane sulfonate (MsO), or perchlorate (CI0 ₄ ). The novel metal oxidants having the general Formula F described herein, form another aspect of the invention. The novel metal oxidants having the general Formula F described herein are useful in oxidative macrocyclization (a ring formation) of a linear peptide, such as for example a compound having the general Formula E. The oxidative macrocyclization may be carried out in an organic solvent, such as, for example, 1 ,1 ,1 ,3,3,3-hexafluoropropan~2~ol (HFIP), in a temperature range of 20 -50 °C.

In the final step, the AG and protecting groups are removed, as described above for step 4 of Scheme 1A, to yield the target biaryi-cyciic peptide of Formula (I).

Many variations on the reactions of Schemes 1 A and 1 B are possible and will suggest themselves to those skilled in the art. For example, in some steps the reaction products may need not be isolated but used in situ in the following reaction. The amine and hydroxyl protecting group chemistry, as well as the timing of protection and deprotection events, may be varied from the particular embodiments described herein. in any of the reactions mentioned hereinbefore and hereinafter, protecting groups may be used where appropriate or desired, even if this is not mentioned specifically, to protect functional groups that are not intended to take part in a given reaction, and they can be introduced and/or removed at appropriate or desired stages. Reactions comprising the use of protecting groups are therefore included as possible wherever reactions without specific mentioning of protection and/or deprotection are described in this specification.

Accordingly, the invention provides a method for making biaryl-cyclic compound of Formula (I)

Formula (!) wherein:

R ¹ and R ⁵ each independently is hydrogen, C _h alky!, or amino-Ci- ₄ alkyl, wherein each amino moiety may optionally include a protecting group;

R ² , R ³ , R ⁴ , R ⁶ , R ⁷ and R ⁸ each independently is hydrogen, Ci- ₄ alkyl, halo, amino, hydroxyl, hydroxy-Ci- ₄ aikyl, cyano or nitro; wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ⁹ and R ¹⁰ each independently is hydrogen, Ci. ₄ alkyl, amino acid residue or a peptide residue; wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ¹¹ is hydrogen, Ci. ₄ alkyi, ary!alkyl, halo-Ci. ₄ alkyl, halo, amino, amino-Ci. ₄ alkyl, hydroxyl, hydroxy-Gi- _S aikyl, hydroxy-ary!aiky!, cyano, cyano-Ci- alkyl; or R ^{1 1} together with the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five- or six- membered ring; and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ¹² is hydroxyl, amino, Ci- ₄ aikoxy, or -NH-Y; wherein Y is carboxy-C - ₅ alkyl, cyano-Ci. ₄ aikyl, or aryicarboxyCi- ₅ alkyl; or Y together with the nitrogen atom to which it is attached may form a five- or six- membered heterocyclic ring, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and n and m each independently is 0 or 1 ; the method comprising: reacting a compound of Formula A: Formula A or a salt or solvate thereof, with a compound of Formula B:

Formula B or a salt or solvate thereof, wherein:

AG is a labile activating group; and may be the same or different on each occurrence; Pg ¹ is an optional amine protecting group; Pg ² is hydrogen, C _h alky!, or hydroxyl protecting group;

-L ¹ -C(0)- may be absent or present, and if present L ¹ is -amino-, -amino-C^alkyl- or -C^sheierocyclic amine-, wherein L ¹ is optionally substituted with one or more of hydroxy-Ci- salkyl-, or hydroxyl-aryl-Ci-salkyl-, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

Pg ³ is an optional amine protecting group;

-L ² - may be absent or present, and if present L ² is: wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R· ² , n and m are as defined for a compound of Formula (I), in the presence of a catalyst and an oxidant, to form a compound of Formula C or a salt or solvate thereof; wherein:

AG is a labile activating group; and may be the same or different on each occurrence;

R ¹ , R ³ , R ⁴ , R ¹⁰ , L ¹ , Pg ¹ , Pg ² and n are as defined for a compound of Formula A; and

R ⁵ , R ⁷ , R ⁸ , R ¹¹ , R ¹² , L ² , Pg ³ and m are as defined for a compound of Formula B; subjecting the compound of Formula C or a salt or solvate thereof to macro!acfamization to prepare the compound of Formula D

Formula D or a salt or solvate thereof; wherein:

AG is a labile activating group; and may be the same or different on each occurrence;

R ¹ , R ³ , R ⁴ , R ¹⁰ , Pg ¹ and n are as defined for a compound of Formula A; and

R ⁵ , R ⁷ , R ⁸ , R ¹¹ , R ¹² and m are as defined for a compound of Formula B; and removing the activating and protecting groups to make the compound of Formula (I); or a pharmaceutically acceptable salt or solvate thereof.

As an alternative approach to obtain the compound of the Formula (I), the present invention relates in another aspect to a method for preparing a compound of Formula (I)

Formula (I) wherein

R ¹ and R ⁵ each independently is hydrogen, Ci- ₄ aikyl, or amino-Ci. ₄ aikyl, wherein each amino moiety may optionally include a protecting group;

R ² , R ³ , R ⁴ , R ⁶ , R ⁷ and R ⁸ each independently is hydrogen, C^alkyl, halo, amino, hydroxyl, hydroxy-Ci. ₄ alkyl, cyano or nitro; wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ⁹ and R ¹⁰ each independently is hydrogen, Ci. ₄ alkyl, amino acid residue or a peptide residue; wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ^{1 1} is hydrogen, Ci. ₄ alkyi, ary!aikyl, halo-Ci- alkyl, halo, amino, amino-Ci- ₄ alkyi, hydroxyl, hydroxy-Ci- _S aikyl, hydroxy-aryialky!, cyano, cyano-Ci- ₄ alkyl; or R ^{1 1} together with the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five-or six- membered ring; and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; R ¹² is hydroxyl, amino, Ci- ₄ alkoxy, or -NH~Y; wherein Y is carboxy-Ci-salkyl, cyano-Ci- ₄ alkyl, or ary!carboxyCi-sa!kyi; or Y together with the nitrogen atom to which it is attached may form a five- or six- membered heterocyclic ring, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and n and m each independently is 0 or 1 ; the method comprising: subjecting to an amidation (amide coupling) reaction a compound of Formula A Formula A or a salt or solvate thereof; and a compound of Formula B

Formula B or a salt or solvate thereof; wherein

AG Is a labile activating group; and may be the same or different on each occurrence;

R ¹ . R ³ . R ⁴ . R ⁵ . R ⁷ . R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , Pg ¹ , Pg ² . Pg ³ , L ¹ , L ² , n and m are as defined hereinbefore; to form a compoifnd of Formula E

Formula E or a salt or solvate thereof; wherein AG is a labile activating group; and may be the same or different on each occurrence;

R\ R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , Pg ¹ , n and m are as defined hereinbefore; treating the compound of Formula E with a metal oxidant having the general Formula F:

[Cu"(OH) .TMEDA] ₂ [X] ₂ Formula F wherein

X is trifluoromethane sulfonate (TfO), methane sulfonate (MsO), or perchlorate (C!0 ₄ ); to make the compound of Formula D

Formula D or a salt or solvate thereof; wherein

AG is a labile activating group; and may be the same or different on each occurrence;

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , Pg ¹ , n and m are as defined hereinbefore; and removing the activating and protecting groups to make the compound of Formula (I); or a pharmaceutically acceptable salt or solvate thereof. In many embodiments of the subject methods the activation group (AG) is a bulky alkyl group, such as ferf-butyi (f-Bu), dimethylpheny! (dmp) and trlpheny! (trityl). Most preferably the activation group (AG) is /erf-butyl.

In many embodiments of the subject methods R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently is hydrogen.

In many embodiments of the subject methods R ⁹ and R ⁱ⁰ each independently is hydrogen. in many embodiments of the subject methods R ⁹ is hydrogen and R ¹⁰ is C _h alky!. in many embodiments of the subject methods R ⁹ and R ¹⁰ each independently is C^alkyl in many embodiments of the subject methods R ¹² is hydroxyl or Ci. alkoxy. in many embodiments of the subject methods R ¹² is -NH-Y, wherein Y is carboxyCi-saikyl or aryicarboxyCi- ₅ aikyl. In certain embodiments of the subject methods R ¹² is -NH-Y, and Y is

C(C0 ₂ Me)CH ₂ C ₆ Hs0H. in certain embodiments of the subject methods R ¹² is -NH-Y, Y is carboxyCi- ₅ alkyl. in certain embodiments of the subject methods R ¹² is -NH-Y, Y is carboxy-CYsalkyi, cyano-

Ci. ₄ alkyl, or aryicarboxyCi- ₅ aikyl; and Y together with the nitrogen atom to which it is attached may form a five- or six- membered heterocyclic ring.

In certain embodiments of the subject methods R ¹² is -NH-Y, Y is carboxyCi- ₅ alkyl and Y together with the nitrogen atom to which it is attached may form a five-membered heterocyclic ring. in certain embodiments of the subject methods R ¹² is -NH-Y, Y is carboxyCYsalkyl and Y together with the nitrogen atom to which it is attached may form a six-membered heterocyclic ring. in certain embodiments, the invention provides a method for making a compound of Formula (I)

wherein:

R\ R ² , R ³ , R ⁴ , R ⁵ , R ^s , R ⁷ and R ^s each independently is hydrogen;

R ⁹ and R ¹⁰ each independently is hydrogen, Ci. ₄ alkyi, amino acid residue or a peptide residue; wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ^M is hydrogen, C _h alky!, ary!a!ky!, halo-Ci- ₄ alkyl, halo, amino, amino-C^alkyl, hydroxyl, hydroxy-Ci. _s alkyl, hydroxy-ary!alkyl, cyano, cyano-C . ₄ alkyl; or R ¹¹ together with the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five- or six- membered ring; and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ¹² is hydroxyl, amino, Ci- ₄ alkoxy, or -NH-Y; wherein Y is carboxy-Ci- ₅ alkyl, cyano-Ci- ₄ aikyl, or aryicarboxyCi- ₅ alkyl; or Y together with the nitrogen atom to which it is attached may form a five- or six- membered heterocyclic ring, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and n and m each independently is 0 or 1 ; the method comprising: reacting a compound of Formula A:

Formula A or a salt or solvate thereof, with a compound of Formula B:

Formula B or a salt or solvate thereof, wherein:

AG is ferf-butyl (f-Bu), dimetbylphenyi (dmp), or triphenyl (trityl); and may be the same or different on each occurrence;

Pg ¹ is an optional amine protecting group;

Pg ² is hydrogen, C _h alky!, or hydroxyl protecting group; -L ¹ -C(0)- may be absent or present, and if present L ¹ is -amino , -amino-Ci-saiky!- or-C ₄ - sbeterocydic amine , wherein L ¹ is optionally substituted with one or more of hydroxy-Ci.salkyl , or hydroxyl~aryl-Ci- ₈ a!kyl-, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

Pg ³ is an optional amine protecting group;

-L ² - may be absent or present, and if present L ² is: wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , n and m are as defined for a compound of Formula (I), in the presence of a catalyst and an oxidant, to form a compound of Formula C or a salt or solvate thereof; wherein:

AG is fenf-butyl (f-Bu), dimethyiphenyl (dmp), ortripheny! (trityi); and may be the same or different on each occurrence;

R ¹ , R ³ , R ⁴ , R ¹⁰ , L ¹ , Pg ¹ , Pg ² and n are as defined for a compound of Formula A; and wherein

R ⁵ , R ⁷ , R ⁸ , R ¹¹ , R ¹² , L ² , Pg ³ and m are as defined for a compound of Formula B; subjecting the compound of Formula C or a salt or solvate thereof to macro!aciamization to prepare the compound of Formula D

Formula D or a salt or solvate thereof; wherein:

AG is tent-butyl (f-Bu), dimethyiphenyl (dmp), or triphenyl (trityi); and may be the same or different on each occurrence;

R ¹ , R ³ , R ⁴ , R ^1Q , Pg ¹ and n are as defined for a compound of Formula A; and wherein R ⁵ , R ⁷ , R ⁸ , R ¹¹ , R ¹² and m are as defined for a compound of Formula B; and removing the activating and protecting groups to make the compound of Formula ); or a pharmaceutically acceptable salt or solvate thereof.

In certain embodiments, the invention provides a method for making a compound of Formula (I)

Formula (I) wherein

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ each independently is hydrogen;

R ⁹ and R ¹⁰ each independently is hydrogen or C .. alkyl;

R ¹¹ is hydrogen, C _h alky!, ary!aikyl, halo-Ci- ₄ alkyl, halo, amino, amino-Ci- ₄ aikyi, hydroxyl, hydroxy-Ci-saikyl, hydroxy-arylaikyl, cyano, cyano-Ci- ₄ alkyl; or R ⁱ¹ together with the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five-or six- membered ring; and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ⁱ² is hydroxyl, amino, Ci- ₄ aikoxy, or -NH-Y; wherein Y is carboxy-C .salkyl, cyano-Ci. ₄ aikyl, or aryicarboxyCi. ₅ alkyl; or Y together with the nitrogen atom to which it is attached may form a five- or six-membered heterocyclic ring, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and n and m each independently is 0 or 1 ; the method comprising: reacting a compound of Formula A: Formula A or a salt or solvate thereof, with a compound of Formula B:

Formula B or a salt or solvate thereof, wherein:

AG is ie/f-butyl (f-Bu), dimethylphenyl (dmp), or triphenyl (trityl); and may be the same or different on each occurrence; Pg ¹ is an optional amine protecting group;

Pg ² is hydrogen, C _h alky!, or hydroxyl protecting group;

-L ¹ -C(G)- may be absent or present, and if present L ¹ is --amino--, -amino-Ci- ₆ alkyl-, or - C _.5 heterocydic amine-, wherein L ¹ is optionally substituted with one or more of hydroxy-Ci. _s alkyl-, or hydroxyl-aryi-Ci-saikyi-, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

Pg ³ is an optional amine protecting group;

-L ² - may be absent or present, and if present L ² is: wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

R\ R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , n and m are as defined for a compound of Formula (I), in the presence of a catalyst and an oxidant, to form a compound of Formula C

or a salt or solvate thereof; wherein:

AG is ferf-butyl (f-Bu), dimethylphenyl (dmp), or triphenyl (trityl); and may be the same or different on each occurrence;

R ¹ , R ³ , R ⁴ , R ¹⁰ , L ¹ , Pg ¹ , Pg ² and n are as defined for a compound of Formula A; and wherein

R ⁵ , R ⁷ , R ⁸ , R ¹¹ , R ¹² , L ² , Pg ³ and m are as defined for a compound of Formula B; subjecting the compound of Formula C or a salt or solvate thereof to macrolactamization to prepare the compound of Formula D

Formula D or a salt or solvate thereof; wherein:

AG is fe/f-butyl (f-Bu), dimethylphenyl (dmp), or triphenyl (trityl); and may be the same or different on each occurrence;

R ¹ , R ³ , R ⁴ , R ¹⁰ , Pg ¹ and n are as defined for a compound of Formula A; and wherein

R ⁵ , R ⁷ , R ⁸ , R ¹¹ , R ¹² and m are as defined for a compound of Formula B; and removing the activating and protecting groups to make the compound of Formula (I); or a pharmaceutically acceptable salt or solvate thereof. in certain embodiments, the invention provides a method for making a compound of Formula (I)

Formula (I) wherein

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ each independently is hydrogen;

R ⁹ and R ¹⁰ each independently is hydrogen or Ci-ialkyl;

R ^{1 1} is Ci. ₄ alkyl, arylalkyl, hydroxy-Ci. ₆ alkyl, hydroxy-aryl alkyl; or R ^{1 1} together with the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five-or six- membered ring; and wherein each hydroxyl moiety may optionally include a protecting group; R ¹² is hydroxyl, amino, Ci- ₄ alkoxy, or -NH~Y; wherein Y is carboxy-Ci-salkyl, cyano-Ci- ₄ alkyl, or arylcarboxyCi-salkyl; or Y together with the nitrogen atom to which it is attached may form a five- or six-membered heterocyclic ring, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and n and m each independently is 0 or 1 ; the method comprising: reacting a compound of Formula A: Formula A or a salt or solvate thereof, with a compound of Formula B:

Formula B or a salt or solvate thereof, wherein:

AG is ferf-butyl (f-Bu), dimethylphenyl (dmp), or triphenyl (trityl); and may be the same or different on each occurrence;

Pg ¹ is an optional amine protecting group;

Pg ² is hydrogen, C _h alky!, or hydroxyl protecting group;

-L ¹ -C(0)- may be absent or present, and if present L ¹ is -amino-, -amino~Ci- _S alkyl- or -C ₄ - sheterocyclic amine-, wherein L ¹ is optionally substituted with one or more of hydroxy-Ci- ₆ alkyl~, or hydroxyi-aryl-Ci-ealkyi- and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

Pg ³ is an optional amine protecting group;

-L ² - may be absent or present, and if present L ² is: wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , n and m are as defined for a compound of Formula (I), in the presence of a catalyst and an oxidant, to form a compound of Formula C

or a salt or solvate thereof; wherein:

AG is tert- butyl (t-Bu), dimethylphenyl (dmp), or triphenyl (trityi); and may be the same or different on each occurrence;

R\ R ³ , R ⁴ , R ¹⁰ , L ¹ , Pg ¹ , Pg ² and n are as defined for a compound of Formula A; and wherein

R ⁵ , R ⁷ , R ⁸ , R ^{1 !} , R ¹² , L ² , Pg ³ and m are as defined for a compound of Formula B; subjecting the compound of Formula C or a salt or solvate thereof to macrolactamization to prepare the compound of Formula D

Formula D or a salt or solvate thereof; wherein:

AG is ferf-butyl (f-Bu), dimethylphenyl (dmp), ortriphenyl (trityl); and may be the same or different on each occurrence;

R ¹ , R ³ , R ⁴ , R ¹⁰ , Pg ¹ and n are as defined for a compound of Formula A; and wherein

R ⁵ , R ⁷ , R ⁸ , R ¹¹ , R ¹² and m are as defined for a compound of Formula B; and removing the activating and protecting groups to make the compound of Formula (I); or a pharmaceutically acceptable salt or solvate thereof.

In certain embodiments, the invention provides a method for making a compound of Formula (I)

Formula (I) wherein

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ each independently is hydrogen;

R ⁹ and R ¹⁰ each independently is hydrogen or Ci. ₄ alkyl; R ¹¹ is Ci. ₄ alkyl, ary!alkyl, hydroxy-Ci- ₆ alkyl, hydroxy-aryl alkyl; or R ¹¹ together with the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five- or six- membered ring; and wherein each hydroxyl moiety may optionally include a protecting group;

R ¹² is Ci. alkoxy, or -NH-Y; wherein Y is carboxy-Ci. ₅ alkyl or arylcarboxyCi.salkyl; and n and m each independently is 0 or 1 ; the method comprising: reacting a compound of Formula A: Formula A or a salt or solvate thereof, with a compound of Formula B:

Formula B or a salt or solvate thereof, wherein:

AG is ferf-butyl (f-Bu), dimethylphenyl (dmp), or triphenyl (trityl); and may be the same or different on each occurrence;

Pg ¹ is an optional amine protecting group;

Pg ² is hydrogen, C _h alky!, or hydroxyl protecting group;

-L ¹ -C(0)- may be absent or present, and if present L ¹ is -amino-, -amino-C . ₆ alkyi- or - Ci-sheterocyciic amine-, wherein L ¹ is optionally substituted with one or more of hydroxy~Ci- salkyl , or hydroxyi-aryi-Ci-saikyi-, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

Pg ³ is an optional amine protecting group;

-L ² - may be absent or present, and if present L ² is: wherein each amino moiety and each hydroxy! moiety may optionally include a protecting group; and

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , n and m are as defined for a compound of Formula (I), in the presence of a catalyst and an oxidant, to form a compound of Formula C or a salt or solvate thereof; wherein:

AG is ferf-butyl (f-Bu), dimethylphenyl (dmp), or triphenyl (trityl); and may be the same or different on each occurrence;

R ¹ , R ³ , R ⁴ , R ^1Q , L ¹ , Pg ¹ , Pg ² and n are as defined for a compound of Formula A; and wherein

R ⁵ , R ⁷ , R ⁸ , R ¹¹ , R ¹² , L ² , Pg ³ and m are as defined for a compound of Formula B; subjecting the compound of Formula C or a salt or solvate thereof to macrolactamization to prepare the compound of Formula D

Formula D or a salt or solvate thereof; wherein:

AG is ferf-butyl (f-Bu), dimethylphenyl (dmp), or triphenyl (trityl); and may be the same or different on each occurrence;

R ¹ , R ³ , R ⁴ , R ¹⁰ , Pg ¹ and n are as defined for a compound of Formula A; and wherein

R ⁵ , R ⁷ , R ⁸ , R ¹¹ , R ¹² and m are as defined for a compound of Formula B; and removing the activating and protecting groups to make the compound of Formula (I); or a pharmaceutically acceptable salt or solvate thereof. in some embodiments of the first method provided by the present invention the reacting of compound of Formula A or a salt or solvate thereof, with a compound of Formula B or a salt or solvate thereof in the presence of a catalyst and an oxidant, to form a compound of Formula C is preceded by determining the oxidation potential of each of compound of Formula A and compound of Formula B. in various embodiments of the first method provided by the present invention the catalyst used in reacting of compound of Formula A or a salt or solvate thereof, with a compound of Formula B or a salt or solvate thereof, to form a compound of Formula C is selected from Fe[5, 10, 15,20-

Tetraphenyi-21H,23H-porphine3CI (Fe[irPP]CI), FeC , [Cu"(OH) .TMEDA] ₂ [CI] ₂ , and Co[saien]

In various embodiments of the first method provided by the present invention the oxidant used in reacting of compound of Formula A or a salt or solvate thereof, with a compound of Formula B or a salt or solvate thereof in the presence of a catalyst and an oxidant, to form a compound of Formula C is selected from mefa-chloroperbenzoic acid (m-CPBA), urea hydrogen peroxide (UHP), 0 ₂ , and di-fe/t-butyl peroxide (DTBP). in various embodiments of the first method provided by the present invention the macrolactamization of a compound of Formula C or a salt or solvate thereof comprises: combining the compound of Formula C with a catalyst mixture, isolating the resulting intermediate compound, and combining the resulting intermediate compound with a coupling agent mixture, thereby obtaining the compound of Formula D or a salt or solvate thereof.

In some embodiments the isolation of the resulting intermediate compound obtained from reacting the compound of Formula C with a catalyst mixture may be optional.

As used herein the expression “isolating the resulting intermediate compound” or “isolated intermediate compound” refers to product of combining the compound of Formula C with a catalyst mixture, wherein the isolated compound has been separated from the reagents used, and/or byproducts formed, in the reaction, as iiiustrated by the appended exampies. "isolated" means that the compound is sufficiently pure to use in the following reaction with the coupling reagent mixture. Some examples of such intermediate compounds are the following compounds designated herein as compound 14a, compound 31b, compound 33b, compound 38b: in some embodiments of the described macrolactamization of a compound of Formula C or a salt or solvate thereof, the catalyst in the catalytic mixture is a palladium compound. According to one embodiment of the process the catalyst in the catalytic mixture is palladium on carbon (Pd/C). in some embodiments of the described macrolactamization of a compound of Formula C or a salt or solvate thereof, the coupling reagent mixture comprises a coupling reagent, a catalyst, and a solvent. According to one embodiment of the process the coupling reagent in the coupling reagent mixture is (benzoinazoM-yloxy)tnpyrrolidinophosphonium hexafluorophosphate (PyBOP) According to one embodiment of the process the catalyst in the coupling reagent mixture is (4- (N,N~dimetby!amino)pyridine (DMAP).

Some examples of compounds according to Formula A, for use in the first method provided by the present invention are the following compounds designated herein as compound 12, compound 31, compound 33, compound 37, compound 38:

Some examples of compounds according to Formula B for use in the first method provided by the present invention are the following compounds designated herein as compound 9a, compound 9b, compound 13: Some examples of compounds according to Formula C synthesized in the first method provided by the present invention are the following compounds designated herein as compound 14, compound 14a, compound 31a, compound 33a, compound 33b, compound 38a, compound 38b:

Some examples of compounds according to Formula D synthesized in the first method provided by the present invention are the following compounds designated herein as compound 15, compound 30, compound 34, compound 40:

Some examples of compounds according to Formula (I) synthesized in the first method provided by the present invention are the following compounds designated herein as compound 16, compound 32, compound 36, compound 39:

As an alternative approach to obtain the compound of the Formula (1), the present invention provides in certain embodiments a method for preparing a compound of Formula (1)

Formula (I) wherein

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently is hydrogen;

R ⁹ and R ¹⁰ each independently is hydrogen, C _h alky!, amino acid residue or a peptide residue; wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ¹¹ is hydrogen, C _h alky!, ary!a!kyi, halo-Ci- alkyl, halo, amino, amino-C^alkyl, hydroxyl, hydroxy-Ci- _S alkyl, hydroxy-ary!aikyi, cyano, cyano-C^alky!; or R ¹¹ together with the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five-or six-membered ring; and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ¹² is hydroxyl, amino, Ci. alkoxy, or ~l\IH~Y; wherein Y is carboxy~Ci- ₅ alkyl, cyano-C^alkyl, or aryicarboxyCi- ₅ alkyl; or Y together with the nitrogen atom to which it is attached may form a five- or six-membered heterocyclic ring, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and n and m each independently is 0 or 1 ; the method comprising: subjecting to an amidation (amide coupling) reaction a compound of Formula A

Formula A or a salt or solvate thereof; and a compound of Formula B

Formula B or a salt or solvate thereof; wherein

AG is tert- butyl (f-Bu), dimetbylphenyi (dmp), ortriphenyl (trityl); and may be the same or different on each occurrence;

Pg ¹ is an optional amine protecting group;

Pg ² is hydrogen, Ci- ₄ alkyl, or hydroxyl protecting group; -L ¹ -C(0)- may be absent or present, and if present L ¹ is --amino· , -amino-Ci- ₆ alkyl-, or - C _4-5 heterocyclic amine-, wherein L ¹ is optionally substituted with one or more of hydroxy-Ci. _s a!kyl~, or hydroxyl-aryi-Ci-salkyl--, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

Pg ³ is an optional amine protecting group;

-L ² - may be absent or present, and if present L ² is: wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ^s , R ¹⁰ , R ¹¹ , R ¹² , n and m are as defined for a compound of Formula (I), to form a compound of Formula E

Formula E or a salt or solvate thereof; wherein AG, R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , Pg ¹ , n and m are as defined hereinbefore; treating the compound of Formula E with a metal oxidant having the general Formula F:

[Cu"(OH) .TMEDA] ₂ [X] ₂ Formula F wherein

X is trifiuoromethane sulfonate (TfO), methane sulfonate (MsO), or perchlorate (CIO ₄ ); to make the compound of Formula D

Formula D or a salt or solvate thereof; wherein AG, R ^! , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , Pg ¹ , n and m are as defined hereinbefore; and removing the activating and protecting groups to make the compound of Formula (I); or a pharmaceutically acceptable salt or solvate thereof.

In certain embodiments of an alternative approach to obtain the compound of the Formula (I), the present invention provides a method for preparing a compound of Formula (I)

Formula (I) wherein

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ each independently is hydrogen;

R ⁹ and R ¹⁰ each independently is hydrogen or Ci- ₄ a!ky!;

R ¹¹ is hydrogen, Ci- ₄ alkyl, arylaikyl, halo-Ci- alkyl, halo, amino, amino-Ci- ₄ aikyl, hydroxyl, hydroxy-Ci-saikyl, hydroxy-arylalkyl, cyano, cyano-Ci- ₄ alkyl; or R ¹¹ together with the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five-or six- membered ring; and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ¹² is hydroxyl, amino, Ci- ₄ aikoxy, or -NH-Y; wherein Y is carboxy-Ci-salkyl, cyano-Ci- ₄ aikyl, or arylcarboxyCi- ₅ aikyl; or Y together with the nitrogen atom to which it is attached may form a five- or six-membered heterocyclic ring, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and n and m each independently is 0 or 1 ; the method comprising: subjecting to an amidation (amide coupling) reaction a compound of Formula A

Formula A or a salt or solvate thereof; and a compound of Formula B

Formula B or a salt or solvate thereof; wherein

AG is fe/f-butyl (f-Bu), dimethylphenyl (dmp), or tripbenyl (trityl); and may be the same or different on each occurrence;

Pg ¹ is an optional amine protecting group;

Pg ² is hydrogen, C _h alky!, or hydroxyl protecting group; -L ¹ -C(0)- may be absent or present, and if present L ¹ is --amino--, -amino-C -ealkyi--, or - C4.sheterocydie amine , wherein L ¹ is optionally substituted with one or more of hydroxy-Ci. salky!-, or hydroxyl-aryl-Ci-saikyl , and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

Pg ³ is an optional amine protecting group;

-L ² - may be absent or present, and if present L ² is: wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , n and m are as defined for a compound of Formula (I), to form a compound of Formula E

Formula E or a salt or solvate thereof; wherein AG, R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , Pg ¹ , n and m are as defined hereinbefore; treating the compound of Formula E with a metal oxidant having the general Formula F:

[Cu"(OH) .TMEDA] ₂ [X] ₂ Formula F wherein

X is trifiuoromethane sulfonate (TfO), methane sulfonate (MsO), or perchlorate (CIO ₄ ); to make the compound of Formula D

Formula D or a salt or solvate thereof; wherein AG, R\ R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , Pg ¹ , n and m are as defined hereinbefore; and removing the activating and protecting groups to make the compound of Formula (I); or a pharmaceutically acceptable salt or solvate thereof.

In certain embodiments of an alternative approach to obtain the compound of the Formula (I), the present invention provides a method for preparing a compound of Formula (I)

Formula (I) wherein

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , and R ⁸ each independently is hydrogen;

R ⁹ and R ¹⁰ each independently is hydrogen or C _h alky!;

R ¹¹ is C _h alky!, arylalkyl, hydroxy-Ci-salkyl, hydroxy-aryl alkyl; or R ⁱ¹ togetherwith the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five-or six- embered ring; and wherein each hydroxyl moiety may optionally include a protecting group;

R ⁱ² is hydroxyl, amino, C^aikoxy, or -NH-Y; wherein Y is carboxy-C . ₅ alkyi, cyano-C^alkyl, or arylcarboxyCi. ₅ aikyl; or Y togetherwith the nitrogen atom to which it is attached may form a five- or six-membered heterocyclic ring, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and n and m each independently is 0 or 1 ; the method comprising: subjecting to an amidation (amide coupling) reaction a compound of Formula A

Formula A or a salt or solvate thereof; and a compound of Formula B

Formula B or a salt or solvate thereof; wherein

AG Is fe/f-butyl (f-Bu), dlmethylphenyl (dmp), or triphenyl (trityl); and may be the same or different on each occurrence;

Pg ¹ is an optional amine protecting group;

Pg ² is hydrogen, C _h alky!, or hydroxyl protecting group; -L ¹ -C(0)- may be absent or present, and if present L ¹ is --amino--, -amino-C -ealkyl--, or - C4.sheterocydie amine , wherein L ¹ is optionally substituted with one or more of hydroxy-Ci. salky!-, or hydroxyl-aryl-Ci-salkyl , and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

Pg ³ is an optional amine protecting group;

-L ² - may be absent or present, and if present L ² is: wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , n and m are as defined for a compound of Formula (I), to form a compound of Formula E

Formula E or a salt or solvate thereof; wherein AG, R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , Pg ¹ , n and m are as defined hereinbefore; treating the compound of Formula E with a metal oxidant having the general Formula F:

[Cu"(OH) .TMEDA] ₂ [X] ₂ Formula F wherein

X is trifiuoromethane sulfonate (TfO), methane sulfonate (MsO), or perchlorate (CIO ₄ ); to make the compound of Formula D

Formula D or a salt or solvate thereof; wherein AG, R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , Pg ¹ , n and m are as defined hereinbefore; and removing the activating and protecting groups to make the compound of Formula (I); or a pharmaceutically acceptable salt or solvate thereof.

In certain embodiments of an alternative approach to obtain the compound of the Formula (I), the present invention provides a method for preparing a compound of Formula (I)

Formula (I) wherein

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ^s , R ⁷ , and R ^s each independently is hydrogen;

R ⁹ and R ¹⁰ each independently is hydrogen or Ci- alkyl;

R ¹¹ is Ci- ₄ alkyl, ary!alky!, hydroxy-Ci-saikyl, hydroxy-aryl alky i; or R ¹¹ together with the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five- or six- membered ring; and wherein each hydroxyl moiety may optionally include a protecting group;

R ¹² is Ci-4alkoxy, or -NH-Y; wherein Y is carboxy-Ci-salkyl or arylcarboxyCi-salky!; and n and m each independently is 0 or 1 ; the method comprising: subjecting to an amidation (amide coupling) reaction a compound of Formula A

Formula A or a salt or solvate thereof; and a compound of Formula B

Formula B or a salt or solvate thereof; wherein

AG is fe/f-butyl (f-Bu), dimethylphenyl (dmp), or triphenyl (trity!); and may be the same or different on each occurrence;

Pg ¹ Is an optional amine protecting group;

Pg ² is hydrogen, C _h alky!, or hydroxyl protecting group;

-U-C(G)- may be absent or present, and if present L ¹ is -amino-, -amino-Ci. _s alkyl- or C- _t -sheierocydic amine-, wherein U is optionally substituted with one or more of hydroxy-Ci- ealky!—, or hydroxyl-aryi-Ci-salkyl-, and wherein each amino moiety and each hydroxyl moiety may optionally indude a protecting group; and

Pg ³ is an optional amine protecting group;

-L ² - may be absent or present, and if present L ² is: wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group; and

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R· ² , n and m are as defined for a compound of Formula (I), to form a compound of Formula E

Formula E or a salt or solvate thereof; wherein AG, R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ^1Q , R ¹¹ , R ¹² , Pg ¹ , n and m are as defined hereinbefore; treating the compound of Formula E with a metal oxidant having the general Formula F:

[Cu"(OH) .TMEDA] ₂ [X] ₂ Formula F wherein

X is trifiuoromethane sulfonate (TfO), methane sulfonate (MsO), or perchlorate (Ci0 ₄ ); to make the compound of Formula D

Formula D or a salt or solvate thereof; wherein AG, R ^! , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ , R ¹⁰ , R ¹¹ , R ¹² , Pg ¹ , n and m are as defined hereinbefore; and removing the activating and protecting groups to make the compound of Formula (I); or a pharmaceutically acceptable salt or solvate thereof. in various embodiments of the alternative method provided by the present invention the amidation coupling reaction of compound of Formula A or a salt or solvate thereof, with a compound of Formula B or a salt or solvate thereof to form a compound of Formula E or a salt or solvate thereof is carried out in the presence of a coupling reagent. According to exemplary embodiments the coupling reagent is selected from 1-Ethyl-3-(3-dimethy!aminopropyl)carbodiimide (EDC) in combination with 1-Hydroxyfaenzotriazole (HOBT); or

N.N'-Dicydohexylcarbodiimide (DCC) in combination with 1~Hydroxybenzotriazoie (HOBT). In various embodiments of the alternative method provided by the present invention the compound of Formula E is treated with a metal oxidant having the general Formula F to make the compound of Formula D or a salt or solvate thereof. In some embodiments of the process the metal oxidant according to general Formula F is [Cu"(OH) ·TMEOA] ₂ [TίO] ₂ (compound 20):

Me ₂ H Me ₂

G S ^N *;ά' '°ϋ''* ^N Ί mot

Me ₂ H Me ₂

Compound 20

Some examples of compounds according to Formula A, for use in the alternative method provided by the present invention are the following compounds designated herein as compound 12a, compound 12c, compound 9, compound 9c, compound 31 , compound 31b:

Some examples of compounds according to Formula B for use in the alternative method provided by the present invention are the following compounds designated herein as compound 13, compound 13a:

Some examples of compounds according to Formula E synthesized in the alternative method provided by the present invention are the following compounds designated herein as compound 17, compound 21 , compound 22, compound 29:

Some examples of compounds according to Formula D synthesized in the alternative method provided by the present invention are the following compound designated herein as compound 15, compound 24, compound 25, compound 30:

Some examples of compounds according to Formula (I) synthesized by the alternative method provided by the present invention are the following compounds designated herein as compound 16, compound 27, compound 28, compound 32:

In another aspect, the present invention provides a compound of Formula D

Formula D or a salt or solvate thereof; wherein:

AG is a labile activating group; preferably AG is tert- butyl (f-Bu), dimethylphenyl (dmp), or triphenyl (trityl); and may be the same or different on each occurrence;

R ¹ and R ⁵ each independently is hydrogen, Ci- alkyl, or amino-Ci- ₄ alkyl, wherein each amino moiety may optionally include a protecting group;

R ³ , R ⁴ , R ⁷ and R ⁸ each independently is hydrogen, Ci. ₄ alkyl, halo, amino, hydroxyl, hydroxy-Ci- ₄ aikyl, cyano or nitro; wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ¹⁰ is hydrogen, C _h alky!, amino acid residue or a peptide residue; wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ^{1 1} is hydrogen, Ci. ₄ alkyl, aryialkyl, halo-Ci- ₄ alkyl, halo, amino, amino-Ci- ₄ aikyl, hydroxyl, hydroxy-Ci- _S alkyl, hydroxy-ary!alkyi, cyano, cyano~Ci- ₄ alkyl; or R ^{1 1} together with the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five-or six- membered ring; and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ¹² is hydroxyl, amino, Ci. ₄ aikoxy, or -NH-Y; wherein Y is earboxy-C . _s alkyi, cyano-C . alkyl, or aryicarboxyCi- ₅ alkyl; or Y together with the nitrogen atom to which it is attached may form a five- er six-membered heterocyclic ring, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

Pg ¹ is an optional amine protecting group; and n and m each independently is 0 or 1 in certain embodiments, the invention provides a compound of Formula D

Formula D or a salt or solvate thereof; wherein:

AG is a labile activating group; preferably AG is fe/f-butyl (/- Bu), dimethylphenyl (dmp), or triphenyl (trityl); and may be the same or different on each occurrence;

R ¹ , R ⁵ , R ³ , R ⁴ , R ⁷ and R ⁸ each independently is hydrogen;

R ¹⁰ is hydrogen, Ci- ₄ alkyl, amino acid residue or a peptide residue; wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ¹¹ is hydrogen, Ci- ₄ a!kyi, ary!aikyl, halo-Ci- ₄ alkyl, halo, amino, amino-C^alkyl, hydroxyl, hydroxy-Ci-saiky!, hydroxy-aryia!kyl, cyano, cyano-Ci- ₄ alkyl; or R ⁱ¹ together with the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five-or six membered ring; and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ⁱ² is hydroxyl, amino, Ci. ₄ alkoxy, or -NH-Y; wherein Y is carboxy-Ci-salkyl, cyano-C^alkyl, or arylcarboxyCi. ₅ aikyl; or Y together with the nitrogen atom to which it is attached may form a five- or six-membered heterocyclic ring, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

Pg ¹ is an optional amine protecting group; and n and m each independently is 0 or 1

In certain embodiments, the invention provides a compound of Formula D

Formula D or a salt or solvate thereof; wherein:

AG is a labile activating group; preferably AG is iert- butyl (f-Bu), dimethyiphenyi (dmp), or triphenyl (trity!); and may be the same or different on each occurrence;

R\ R ⁵ , R ³ , R ⁴ , R ⁷ and R ⁸ each independently is hydrogen;

R ¹⁰ is hydrogen or Ci. ₄ alkyl; R ¹¹ is hydrogen, Ci. ₄ alkyl, arylalkyl, halo-Ci^alkyi, halo, amino, aminO Ci- ₄ alkyi, hydroxyl, hydroxy-Ci-salkyl, hydroxy-arylalkyl, cyano, cyano-Ci-4alkyl; or R ¹¹ together with the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five-or six- membered ring; and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

R ¹² is hydroxyl, amino, Ci- ₄ alkoxy, or -NH-Y; wherein Y is carboxy~Ci- ₅ alkyl, cyano-Ci- ₄ alkyl, or aryicarboxyCi- ₅ alkyl; or Y together with the nitrogen atom to which it is attached may form a five- or six-membered heterocyclic ring, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

Pg ¹ is an optional amine protecting group; and n and m each independently is 0 or 1. in certain embodiments, the invention provides a compound of Formula D

Formula D or a salt or solvate thereof; wherein:

AG is a labile activating group; preferably AG is teri- butyl (f-Bu), dimethylphenyl (dmp), or triphenyl (trityl); and may be the same or different on each occurrence;

R ¹ , R ⁵ , R ³ , R ⁴ , R ⁷ and R ⁸ each independently is hydrogen; R ¹⁰ is hydrogen or Ci- ₄ alkyl;

R ^M is C _h alky!, arylaikyl, hydroxy-Ci. _s alkyl, hydroxy-aryl alkyl; or R ¹¹ together with the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five- or six- membered ring; and wherein each hydroxyl moiety may optionally include a protecting group;

R ¹² is hydroxyl, amino, Ci- ₄ alkoxy, or -NH-Y; wherein Y is carboxy-Ci-salkyl, cyano-Ci- ₄ alkyl, or arylcarboxyCi. ₅ alkyl; or Y together with the nitrogen atom to which it is attached may form a five- or six-membered heterocyclic ring, and wherein each amino moiety and each hydroxyl moiety may optionally include a protecting group;

Pg ¹ is an optional amine protecting group; and n and m each independently is 0 or 1.

In certain embodiments, the invention provides a compound of Formula D

Formula D or a salt or solvate thereof; wherein:

AG is a labile activating group; preferably AG is ferf-butyl (f-Bu), dimethyipbenyl (dmp), or triphenyi (trityl); and may be the same or different on each occurrence; R ¹ , R ⁵ , R ³ , R ⁴ , R ⁷ and R ⁸ each independently is hydrogen;

R ¹⁰ is hydrogen or Ci-4alkyl;

R ¹¹ is Ci . ₄ aikyL arylalkyl, hydroxy-C . ₆ alkyl, hydroxy-arylalkyi; or R ¹¹ together with the carbon atom to which it is attached and together with the adjacent nitrogen atom, may form a five-or six-membered ring; and wherein each hydroxyl moiety may optionally include a protecting group;

R ¹² is Ci- alkoxy, or -NH-Y; wherein Y is carboxy-G . ₅ a!kyl or arylcarboxyCi- ₅ alkyl;

Pg ¹ is an optional amine protecting group; and n and m each independently is 0 or 1.

Compounds of the Formula D may be prepared as described herein.

Some examples of compounds according to Formula D, provided by the present invention are the following compounds designated herein as compound 15, compound 24, compound 25, compound 30, compound 34, compound 40: A compound of the Formula D may be used, inter alia, for the synthesis of pharmaceutically active substances, preferably biaryl-bridged cyclic peptides, such as for example arylomycin and analogues thereof, for example arylomycin A (compound 2), RP66453 (compound 4), and GG775 (compound 3), as described hereinafter. In some embodiments a compound of Formula D is used for the synthesis of an antimicrobial agent.

Thus, in another aspect, the present invention relates to a method for preparing arylomycin and arylomycin analogue compounds, such as, for example, arylomycin A (compound 2), said process comprising subjecting a compound of Formula D

Formula D or a salt or solvate thereof; wherein:

AG is a bulky alkyl group, preferably tert- butyl (f-Bu);

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , and R ⁸ each independently is hydrogen; R ¹⁰ and R ¹¹ each independently is methyl;

R ¹² is OH or a protecting group, preferably OMe or OBn; Pg ¹ is H or a protecting group, preferably Boc or CBz; n is 0; and m is 1 ; to removal of AG and Pg ¹ as provided herein to make compound 16; attachment of a peptide chain (CH ₃ ) ₂ CH(CH ₂ )i ₂ -C(0)~A/~Me,/V~D~Ser-D-A!a-G!y-0H (also known as n-C15~D-MeSer~D~Ala-Gly~QH) having the structural formula: (Formula P) to the amino side chain of compound 18; followed by hydrolysis of the resulting methylcarboxilate to make arylomycin A (compound 2).

The peptide chain (CH ₃ ) ₂ CH(CH ₂ )i ₂ -C(0)-N-Me,N-D-Ser~D~Ala-Gly~0H may be prepared as described by Jian Liu et al. (Synthesis and Characterization of the Arylomycin Lipoglycopepiide Antibiotics and the Crystallographic Analysis of Their Complex with Signal Peptidase. J. Am. Chem. Soc. 2011 , 133, 44, 17869-17877); or as described by DufourJ. et al. (Intramolecular Suzuki-Miyaura Reaction for the Total Synthesis of Signal Peptidase Inhibitors, Arylomycins A ₂ and B ₂ . Chem. Eur. J. 2010, 16, 10523 - 10534).

The attachment of the peptide chain n~C15-D-MeSer-D-A!a-G!y-OH (Formula P) to the amino side chain of compound 16 may be carried out, for example, as described by Jian Liu et al., or as described by Dufour J. et ai. In certain embodiments, the attachment of the peptide chain (Formula P) to the amino side chain of compound 18 is carried out by adding n-C15~D-MeSer- D-A!a-G!y-OH (1 eq.), 3-(diethyloxyphosphoryloxy)-1 ,2,3-benzotriazin-4(3H)-one (DEPBT) (10 eq.) and NaHC03 (10 eq.) to a solution of compound 16 (1 eq.) in THF, at 0°; allowing the resulting mixture to warm to room temperature and stirring for 24 hours.

Several variations for performing the hydrolysis of the resulting methylcarboxilate are possible and will suggest themselves to those skilled in the art. For example, the hydrolysis may be carried out as described by Jian Liu et ai., by dissolving the methyicarboxilate in 1 ml of DCE under Argon, followed by addition of ethyltin hydroxide (10 eq.), at room temperature; and heating the reaction mixture to 70 °C for 4 hours. Alternatively, the hydrolysis may be carried out as described by Dufour J. et ai., by using AIBr ₃ (1 M in CH ₂ Br ₂ , 20 eq.) which is slowly added at 0 °C, under argon to a solution of the arylomycin ester in EtSH. The solution is allowed to warm to room temperature and stirred for 6 hours. Volatiles are evaporated under reduced pressure to yield a residue taken up in a minimum of CH ₂ CI ₂ and quenched by a few drops of MeOH at 0 °C. Alternatively, the hydrolysis may be carried out by dissolving the arylomycin ester (1 eq.) in THF, cooling the solution was to 0 °C, followed by slowly adding 2M LiOH (aq.). Allowing the solution to warm to room temperature and stirring vigorously for 2 hours. in another aspect, the present invention relates to a method for preparing RP66453 (compound 4), said process comprising subjecting a compound of Formula D

Formula D or a salt or solvate thereof; wherein:

AG is a bulky alkyl group, preferably tert- butyl (f-Bu);

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ and R ⁱ⁰ each independently is hydrogen; R ¹¹ is sec-butyl; R ¹² is

Pg ¹ is H or a protecting group, preferably Boc or CBz;

Pg ² is OH or a protecting group, preferably GMe or GBn; n is 1 ; and m is 1 ; to removal of AG and Pg ¹ as provided herein to make compound 39; and converting compound 39 to RP66453 (compound 4).

In another aspect, the present invention relates to a method for preparing G0775 (compound 3), said process comprising subjecting a compound of Formula D

Formula D or a salt or solvate thereof; wherein:

AG is a bulky alkyl group, preferably fe/f-buty! (f-Bu),

R ¹ , R ³ , R ⁴ , R ⁵ , R ⁷ , and R ^® each independently is hydrogen;

R ¹⁰ and R ¹¹ each independently is methyl;

R ¹² is OH or a protecting group, preferably GMe or OBn;

Pg ¹ is H or a protecting group, preferably Boc or CBz; n is 0; and m is 1 ; to removal of AG and Pg ¹ as provided herein; attachment of diamino butyric acid to the amino side chain of the resulting compound; followed by attachment of 2-(4-(tert-butyl)phenyl)~4~methyipyrimidine-5-carboxylic acid to the diamono butyric acid; hydrolysis; and addition of amino acetonitrile to make the compound identified herein as G0775 (compound 3).

In certain embodiments, the addition of amino acetonitrile may be carried out as described by Smith A.P et ai. (Optimized aryiomycins are a new class of Gram-negative antibiotics. Nature, 2018, 561, 189-194). Definitions

As used in the specification and the appended claims, the singular forms "a," "an" and "the" are not intended to exclude the plural unless the context clearly dictates otherwise

"Alkyl" means the monovalent linear or branched saturated hydrocarbon moiety, consisting solely of carbon and hydrogen atoms. “Ci^a!kyl” refers to an alkyl group having one to four carbon atoms, such as for example methyl, ethyl, propyl, isopropyl, isobutyl, sec-butyl, tert-butyl. “Ci-saiky!” refers to an alkyl group having one to five carbon atoms, without being limited to, such as for example methyl, ethyl, propyl, isopropyl, isobutyl, sec-butyl, tert-butyl, pentyl and the like.

“Amino” means a moiety of the formula -NRR' wherein R and R' each independently is hydrogen or alkyl as defined herein.

“Alkylamino” and “aminoalkyl” means a moiety of the formula -NRR' wherein one of R and R' is hydrogen and the other is alkyl as defined herein. For example “amino-C^alky!” means a moiety of the formula -NRR' wherein one of R and R’ is hydrogen and the other is Ci-4aikyl as defined herein.

“Diaikylamino” means a moiety of the formuia -NRR’ wherein each of R and R' is alky! as defined herein.

"Alkoxy” means a moiety of the formula -OR, wherein R is an alkyl moiety as defined herein. “Ci. alkoxy” refers to an aikoxyi group having one to four carbon atoms, such as for example, without being limited to, methoxy, ethoxy, isopropoxy, and the like.

"A!ky!ene" means a linear saturated divalent hydrocarbon radical of one to six carbon atoms or a branched saturated divalent hydrocarbon radical of three to six carbon atoms, such as for exampie, without being limited to, methylene, ethylene, 2,2-dimethylethy!ene, propylene, 2-methyl propylene, butylene, pentyiene, and the like.

"Aryl" means a monovalent cyclic aromatic hydrocarbon moiety consisting of a monoaromatic ring, for exampie phenyl, which may be optionally substituted as defined herein. "Ary!aikyl" means a moiety of the formula -RR' where R is an aiky!ene group and R' is an aryl group as defined herein; such as for example, without being limited to, benzyl, hydroxybenzyl, phenyiethyl, and the like.

"Carboxy" means a group of the formula -C(G)-GH.

"Activating group" refers to an organic group introduced at the ortho position of phenol in Tyr, Hpg, Tyr derivatives and Hpg derivatives. The activating group is intended to assist in the oxidative coupling of Tyr and Hpg derivatives for the efficient assembly of biaryl-bridged cyclic peptides. Exemplary activating groups include, bulky alkyl groups, such as, without being limited to, tert-butyl group

"Protecting group" means a group which selectively blocks one reactive site in a multifunctional compound such that a chemical reaction can be carried out selectively at another unprotected reactive site in the meaning conventionally associated with it in synthetic chemistry. Certain processes of this invention rely upon the protective groups to block reactive nitrogen and/or oxygen atoms present in the reactants.

"Amino-protecting group" refers to an organic group intended to protect the nitrogen atom against undesirable reactions during synthetic procedures. Exemplary nitrogen protecting groups include, without being limited to, trifluoro acetyl, acetamido, benzyl (Bn), benzyloxycarbonyl (carbobenzyloxy, CBZ), p-methoxybenzyloxycarbonyl, p-nitrobenzyloxycarbonyl, tert- butoxycarbonyi (BOC), and the like. A person skilled in the art will know how to choose a group for the ease of removal and for the ability to withstand the conditions of a specific reaction.

“Hydroxyl protecting group” refers to any group that is appropriate for reversible protection of hydroxy groups. Exemplary hydroxyl protecting groups include, without being limited to, diphenyl- ieri-buty!si!yi, tert-buiy!dimetbylsily!, irimethylsiiyi, acetyl, benzoyl, iert-buioxycarbonyi (Boc), benzyloxycarbonyl, tetrahydropyranyl, benzyl, p-methoxybenzyl, methoxymethyl, and the like. A person skilled in the art will know how to choose a group for the ease of removal and for the ability to withstand the conditions of a specific reaction. “Hydroxy-arylalkyl” means a moiety of the formula HO-RR'- where HO- is hydroxyl, R is an alkylene group and R' is an aryl group as defined herein; such as for example, without being limited to, hydroxybenzyl group (HO-C ₆ H ₄ -CH ₂ -).

"Pharmaceutically acceptable” means that which is useful in preparing a pharmaceutical composition that is generally safe, non-toxic, and neither biologically nor otherwise undesirable and includes that which is acceptable for veterinary and / or human pharmaceutical use.

"Pharmaceutically acceptable salts" of a compound means salts that possess the desired pharmacological activity of the parent compound. It should be understood that all references to pharmaceutically acceptable salts include solvent addition forms (solvates) or crystal forms (polymorphs) as defined herein, of the same acid addition salt.

"Solvates” means solvent additions forms that contain either stoichiometric or non-stoichiometric amounts of solvent. Some compounds have a tendency to trap a fixed molar ratio of solvent molecules in the crystalline solid state, thus forming a solvate if the solvent is water the solvate formed is a hydrate, when the solvent is alcohol, the solvate formed is an alcoholate. Hydrates are formed by the combination of one or more molecules of water with one of the substances in which the water retains its molecular state as H ₂ 0, such combination being able to form one or more hydrate.

EXPERIMENTAL SECTION

General information

All reagents and solvents were purchased from Sigma-Aldrich, Alfa-Aesar, Strem Chemicals or Fluka and were used without further purification. Column chromatography was performed on Merck chromatographic silica gel (40-60 pm). TLC analyses were performed using Merck silica gel glass plates 60 F ₂₅₄ . NMR spectra were recorded on Bruker DPX400, or DMX500 instruments. Chemical shifts are given in ppm and relative to Me ₄ Si as an internal standard or to the residual solvent peak. High-resolution mass spectrometry (HRMS) data were obtained using an LTQ Orbitrap XL ETD (Thermo Fisher Scientific, Germany & USA) high-resolution mass spectrometer. HPLC analysis was carried out on Agilent 1260 instrument equipped with a G4212- 60008 photodiode array detector, ES-MS Advion Expression unit and an Agilent reverse phase ZORBAX Eclipse plus C18 3.5 pm column (4.6 X 100 mm). Cyclic voltammetry measurments were conducted with EmState 3+ potentiostat (PalmSens). WE: glassy carbon electrode, 3 mm diameter; CE: Pt wire, 0.5 mm diameter. XPS data were collected using an X-ray photoelectron spectrometer ESCALAB 250 ultrahigh vacuum (1 - 10 ⁹ bar) apparatus with an AIKa X-ray source and a monochromator. The X-ray beam size was 500 pm and survey spectra was recorded with pass energy (PE) 150eV and high energy resolution spectra were recorded with pass energy (PE) 20eV. To correct for charging effects, all spectra were calibrated relative to a carbon C 1s peak positioned at 284.8 eV. Processing of the XPS results was carried out using AVANTGE program.

1 Oxidative Coupling of L-tyrosine

This study was devoted to exploring the conditions for the synthesis of di-tyrosine (compound 11b) (Scheme 2), which is the simplest biaryl-bridged linear peptide, since previous attempts to dimerize two tyrosine residues by chemoenzymatic, photochemical, electrochemical or metal oxidation have met with only limited success. Likewise, the present inventors’ efforts to identify catalytic systems suitable for the oxidative dimerization of /V-Cbz-L-Tyr-OMe (compound 8b) were not successful (Table S1). Without being bound by theory, a number of reasons may account for this lack of success: (i) the relatively high oxidation potential of tyrosine precludes selective oxidation under mild conditions (Perez-Rodriguez, S. et al., First total synthesis of dioxepine bastadin 3. Org. Biomol. Chem. 2012, 10 (34), 6945-6950); (ii) the di-tyrosine coupling product is more reactive than the parent tyrosine amino acid and is therefore prone to overoxidation (Lee, D.-l. et al., Large-scale production of N,N'-diBoc-dityrosine and dityrosine by HRP-catalyzed N-Boc-l-tyrosine oxidation and one-step chromatographic purification. Proc. Biochem. 2011, 46 (1), 142-147); and (iii) the spin density in the tyrosine radical intermediate is distributed over the ortho- and para- carbon atoms as well as at the hydroxyl group, leading to a mixture of coupling and dehydrogenation products (Eickhoff, H. et al., Oxidative phenol coupling — tyrosine dimers and libraries containing tyrosyl peptide dimers. Tetrahedron 2001, 57 (2), 353- 364).

Table SI. Oxidative coupling of /V-Cbz-L-Tyr-OMe (compound 8b) under different oxidative coupling conditions (selected examples). ⁰

Scheme 2

entry catalyst (\ mol "<>) solvent (0.1 M) yield r„)

2 I n ⁽ N5 i DTBP (1.5) HFIP

3 Fe(C10 ₄ )3 (2.5) TBHP (l.l) HFIP

4 Co[TPP]Cl (1) O2 ( 1 atm) HFIP

5 Fe[TPP]Cl (1) TBHP (l.l) MeCN

6 Fe[TPP]Cl (1) TBHP (l.l) TFE

7 Fe[TPP]Cl (1) TBHP (l.l) HFIP

8 Fe[TPP]Cl (5) TBHP (l.l) HFIP

9 Fe[TPP]Cl (1) UHP (l) HFIP 10% ^b

10 Fe[TPP]Cl (1) m-CPBA (1) HFIP trace

“Reaction conditions: V-C'b / - L-Ty r -O M c 8b (0.06 mmol, 20 mg, 1 equiv) was stirred with the catalyst and oxidant for 16-24h at r.t. Isolated yield by prep-HPLC. Abbreviations: TPP= 5.10.15.20-Tctraphcnyl-2 \ 11.2311- porphine, DTBP = di-ieri-butyl peroxide, TBHP = «r -butyl hydroperoxide, UHP = urea hydrogen-peroxide, m-CPB A = meia-chloroperoxybenzoic acid, HFIP = l,l,l,3,3,3-hexafluoropropan-2-ol, TFE = 2,2,2-trifluoroethanol.

2 Oxidative coupling of Cbz-l-(2-t-Bu)Tyr-OMe (compound 9b)

Next, the present inventors examined the idea of facilitating the oxidative coupling of tyrosine by introducing a labile activating group (AG) at the ortho-position of the phenolic moiety — a route that would comply with the electronic and steric requirements of tyrosine as a coupling partner under mild catalytic oxidative coupling conditions.

In an exploitation of the activating group strategy, Boc-L-(2-f-Bu)Tyr-OMe (compound 9a) and Cbz-L-(2-f-Bu)Tyr-OMe (compound 9b) were prepared from tyrosine methyl ester (compound 8a) (fe/f-butyl chloride in methanesulfonic acid, then Cbz or Boc protection) on a 50-g scale in 70% yield (Scheme 2A).

Scheme 2A. Conditions: (a) f-BuCl (5 equiv), MsOH (5 equiv), 50 °C, 12 h; then (b) B0C ₂ O (1.1 equiv), Et ₃ N (1.5 equiv.), MeOH, rt, 18 h, 70% yield, or CbzCl (1 equiv.), Na ₃ CO ₃ (2 M), H ₂ O/THF, rt, 16 h, 70% yield (c) Fe[TPP]Cl (0.5 mol %), UHP (1 equiv), HFIP, rt, 15 min, 98% and 97%. yields (d) TFA/DCM 1: 1 (0.1 M), rt, 4 h; then TfOH (10 equiv), HFIP, rt, 16 h, 92% yield, or Pd-C (5 mol %), H ₂ (1 atm), MeOH, rt, 2 h; then TfOH (10 equiv), HFIP, rt, 16 h, 92% yield.

The oxidation potential of activated tyrosine compound 9b was found to be lower by about 160 mV (vs Ag/AgCI, CH ₃ CN) than that of non-activated tyrosine compound 8b (Figure 2B).

Then, the conditions for oxidative dimerization were studied. Table S2 provides the results of oxidative coupling of Cbz-L-(2-f-Bu)Tyr-OMe (compound 9b) under different conditions. Consequently, the two activated tyrosine residues compound 9a and compound 9b underwent oxidative dimerization within 15 min under the mild catalytic coupling conditions that have been developed in our group [namely, Fe[TPP]CI (0.5 mol %), urea hydrogen peroxide (UHP, 1 equiv), 1 ,1 ,1 ,3,3,3-hexafluoropropan-2-ol (HFIP), room temperature (rt)] (Shalit, H. et al., meso- Tetraphenylporphyrin Iron Chloride Catalyzed Selective Oxidative Cross-Coupling of Phenols. J. Am. Chem. Soc. 2017, 139 (38), 13404-13413; Libman, A. et al., Synthetic and Predictive Approach to Unsymmetrical Biphenols by Iron-Catalyzed Chelated Radical-Anion Oxidative Coupling. J. Am. Chem. Soc. 2015, 137 ( 35), 11453-11460). The desired 2, 2'-(di-f-Bu)di-tyrosine products compound 10a and compound 10b were isolated in excellent 97% and 98% yields, respectively. Without being bound by theory, the significant improvement in the coupling efficiency and selectivity of the activated tyrosine residues compound 9a and compound 9b in comparison to non-activated tyrosine compound 8b (Figure 2C) may be attributed to the ability of the activating group (fe/f-butyl group) to: (i) facilitate the oxidation step, thereby increasing the lifespan of the phenoxyl radical intermediate significantly, (ii) prevent the sequential oligomerization of di tyrosine, and (iii) ensure selective coupling at the o/fbo-position.

Table S2. Oxidative coupling of Cbz-L-(2-/-Bu)Tyr-OMe (compound 9b) under different conditions (selected examples). ⁰

1 Fe[TPP]Cl (0.5) 0 ₂ ( 1 atm) HFIP 2 2

2 Fe[TPP]Cl (0.5) TBHP (l) HFIP 1 14

3 Fe[TPP]Cl (0.5) m-CPBA (1) HFIP 1 86 (81)

4 Fe[TPP]Cl (0.5) UHP (1) HFIP 0.25 97 (97)

5 Fe[TPP]Cl (0.5) m-CPBA (1) TFE 1 92 (75)

6 Fe[TPP]Cl (0.5) UHP (1) TFE 1 69

7 Fe[TPP]Cl (0.5) m-CPBA (1) DCE 1 50

8 Fe[TPP]Cl (0.5) UHP (1) DCE 1 trace

9 Fe[TPP]Cl (0.5) UHP (1) MeCN 1 8

10 FeCh (2.5) m-CPBA (1) HFIP 1 67 11 FeCb (2.5) UHP (1) HFIP 1 39 12 FeCh (2.5) TBHP (l) HFIP 1 16

13 Co(Salen) (1) Air (1 atm) HFIP 1 trace [Cu ⁿ (OH).TMEDA] ₂ Cl2

14 Air (1 atm) HFIP 1 trace (2)

15 UHP (1) HFIP 1 trace “Reaction conditioned: Cb / - L-(2 -/ - B n) Ty r-0 M c 9b (0.05 mmol, 20 mg, 1 equiv) was stirred with the catalyst and oxidant at r.t. HPLC yield. Ίh parenthesis: isolated yield. Abbreviations: TPP=5. 10.15.20-Tctraphcnyl-2 \ 11.2311- porphine, Co(Salen)= \. \ 'Bis(salicylidcnc)cthylcncdiaminocobalt(II). TBHP= /«//-butyl hydroperoxide, UHP= urea hydrogen-peroxide, TMEDA= Tetramethylethylenediamine, ///-CPBA= meia-chloroperoxybenzoic acid, HFIP= l,l,l,3,3,3-hexafluoropropan-2-ol, TFE= 2,2,2-trifluoroethanol, DCE= 1 ,2-dichloroethane.

HPLC Chromatogram of Entry 4 in Table S2 is shown in Figure 2A.

3 Dealkylation of fe/ -butyl groups

The removal of the tert- butyl groups from 2,2'-(di-M3u)-di-tyrosine compound 10a and compound 10b turned out to be a challenging task, as the reported procedures for Friedel-Crafts dealkylation failed to afford di-tyrosine compound 11 (Table S3). Finally, the present inventors realized that removal of the /V-carbamate protecting groups [2,2,2-trifluoroacetic acid (TFA) in dichloromethane (DCM) for compound 10a or Pd-C/H ₂ in methanol for compound 10b] prior to the Friedel-Crafts dealkylation [triflic acid (TfOH) in HFIP] was necessary to prevent undesired side reactions. Under these conditions, multigram quantities of di-tyrosine compound 11 were obtained from compound 10a and compound 10b in 92% and 90% yields, respectively.

Scheme 3 Table S3. Dealkylation of /c/7- butyl groups from dityrosine compound 10a and compound 10b under different conditions (selected examples). ^{01 3} temp yi

<°o 1 10b AICT _, (20) benzene 60 0

MeN0 ₂ :

2 10a AICI ₃ (20) -40 to r.t. 0 toluene 1: 10

3 10a Nafion-H toluene reflux N.R.

4 10a Dowex resin toluene 100 N.R.

5 10a TfOH (20) toluene r.t. N.R.

6 10b TfOH (20) HFIP r.t. decomposition

7 10a TfOH (20) HFIP r.t. decomposition

8 10b TfiO/TfOH 20:1 (20) HFIP r.t. decomposition

9 10a TfOH (20) TFE r.t. N.R.

1. Pd/C 5%, IT 1 atm TMeOH aReaction conditioned: protected 2.2 ^' -(di-/-Bn)-di-tyrosinc lOa/lOb (0.1 mmol, 1 equiv), solvent (1 mL), overnight. Hsolated yield for two steps. Abbreviations: TfOH = Trifluoromethanesulfonic acid, TFA = Trifluoroacetic acid, Tf ₂ 0 = Trifluoromethanesulfonic anhydride, S.M.= starting material, N.R. = no reaction 4 Oxidative cross-coupling Studies (Approach A, step 2)

This studies focused on developing step 2 of Approach A (Scheme 1A) for synthesis of macrocyclic peptide compounds of Formula (I).

4.1 Study of Oxidative cross-coupling between compound 12 and compound 13 (Approach A, step 2)

To examine the feasibility of Approach A, A/-Boc-/\/-Me-L-(2-f-Bu)Hpg-OBn (compound 12) and A/-Cbz-L-Ala-L-(2-f-Bu)Tyr-OMe (compound 13) (Scheme 4), which constitute the units comprising the arylomycin cyclic core compound 16, were prepared and examined as coupling partners in oxidative cross-coupling reactions. Compound 16 is a key cyclic intermediate in the synthesis of both arylomycin (compound 2, Figure 1 A) and G0775 (compound 3, Figure 1A).

Although the two coupling partners share high molecular similarity, the oxidation potential of activated Tyr compound 13 is significantly lower than that of activated Hpg compound 12 — by about 170 mV (Shalit, H. et al., meso-Tetraphenylporphyrin Iron Chloride Catalyzed Selective Oxidative Cross-Coupling of Phenols. J. Am. Chem. Soc. 2017, 139 (38), 13404-13413). The present inventors therefore drew on the recent work of their group (Shalit, H. et al., 2017) showing that cross-coupling of two phenols by an iron-porphyrin catalyst is chemoselective when the iron binds selectively to the less reactive phenol (compound 12 in this case), while abstracting a hydrogen atom from its readily oxidized coupling partner (compound 13 in this case). However, since the two coupling partners have comparable binding strengths to the iron porphyrin catalyst (Figure 6), it was expected that the cross-coupling would be challenging. Indeed, poor cross coupling selectivity was obtained when compound 12 (1 equiv) and compound 13 (1 equiv) were reacted in HFIP; under these conditions activated tyrosine compound 13 underwent rapid self coupling. Improved results were obtained when compound 13 (1 equiv) and meta- chloroperbenzoic acid (mCPBA, 2 equiv) were added portion-wise to a solution of compound 12 (3 equiv) and Fe[TPP]CI (1 mol %) in 1,2,-dichloroethane. Under these conditions, the desired biaryl-bridged linear peptide compound 14 was isolated in 48% yield.

Results

A. Table S4 provides the results of oxidative cross-coupling of A/-Cbz-L-Ala-L-(2-f- Bu)Tyr-OMe (13) and A/-Boc-/V-Me-L-(2-f-Bu)Hpg-OBn (12) under different conditions. Table S4. Oxidative cross-coupling of /V-Cbz-L-Ala-L-(2-f-Bu)Tyr-OMe (13) and A ^' -Boc-A ^' -IVIc- L-(2-f-Bu)Hpg-OBn (12) under different conditions (selected examples)."

Scheme 4 entry solvent (0.1 M) oxidant (\ equiv) viekl ("«)*

HFIP UHP (1.2) <10

2 HFIP UHP (1.2) 25

3 ^d HFIP UHP (1.2) 35

4 d TFE UHP (1.2) 24

“Reaction conditions: 13 (0.1 mmol, 45.6 mg, 1 equiv), 12 (0.3 mmol, 128 mg, 3 equiv), solvent (1 mL). Isolated yield. ^C 1 equiv of 12 & 3 equiv of 13 were used. ^d 13 and oxidant were added in 4 portions every 20 min. Abbreviations: UHP= urea hydrogen-peroxide, /«-CPBA= meia-chloroperoxybenzoic acid, HFIP= 1, 1,1, 3,3,3- hexafluoropropan-2-ol, TFE= 2,2,2-trifluoroethanol, DCE= 1,2-dichloroethane.

B. Figure 3 shows the oxidative cross-coupling experiments between N-Boc-N-Me-L- (2-t-Bu)Hpg-OBn (compound 12) and N-Cbz-L-Ala-L-(2-t-Bu)Tyr-OMe (compound 13) as was monitored by HPLC.

Preliminary studies by the present inventors revealed that poor cross-coupling selectivity is obtained when compound 12 (1 equiv) and compound 13 (1 equiv) were reacted in 1 :1 ratio (Figure 3, chromatograms A-C). Under these conditions activated tyrosine compound 13 underwent rapid self-coupling, affording compound [13] as the major product (Scheme 5). Improved results were obtained when activated tyrosine compound 13 (1 equiv) and rn-CPBA were added portion-wise to a solution of compound 12 (3 equiv) and Fe[TPP]CI in DCE (Figure S3, chromatogram D). Under these conditions the cross-coupling product 14 was isolated in 48% yield.

Scheme 5

C. Cyclic voltammetry measurements

Figure 4 provides the cyclic voltammetry measurements of compound 12 and compound 13 in DCE (3 mM) with tetrabutylammonium hexafluorophosphate (TBAP) as the supporting electrolyte (50 mM) vs Ag/0.01 M AgN03 in 0.1 M TBAP/CH ₃ CN, scan rate = 50 mV s-1.

D. Competitive binding experiment

¹ H-NMR competitive binding experiment of A/-Boc-/V-Me-L-(2-f-Bu)Hpg-OBn (compound 12) or/and Cbz-L-Ala-(2-f-Bu)Tyr-OMe (compound 13) to Fe[TPP]CI in the presence of HFIP were conducted in order to reveal the binding strength of the two coupling partners (Shalit, H. et al. , 2017). These experiments have shown that the two phenol-based amino acids bind to the iron in a non-selective manner.

A) A solution of Ag ₂ C0 ₃ (6 mg, 22.5 pmol, 9 equiv), Fe[TPP]CI (1.7 mg, 2.5 pmol, 1 equiv) and A/-Boc-/V-Me-L-(2-f-Bu)Hpg-OBn (12) (7.5 mg, 17.5 pmol ,7 equiv) in CDCI ₃ (600 pL) was stirred at room temperature for 24 hours, then ¹ H-NMR spectrum of Fe[TPP][12] (compound 12a) complex was recorded (Figure 5A).

B) A solution of Ag ₂ C0 ₃ (6 mg, 22.5 pmol, 9 equiv), Fe[TPP]CI (1.7 mg, 2.5 pmol, 1 equiv) and Cbz-Ala-(2-f-Bu)Tyr-OMe (13) (8 mg, 17.5 pmol, 7 equiv) in CDCI ₃ (600 pL) was stirred at room temperature for 24 hours, then ¹ H-NMR spectrum of Fe[TPP][13] (compound 13a) complex was recorded (Figure 5B). C) A solution of A/-Boc-/V-Me-L-(2-f-Bu)Hpg-OBn (compound 12) (7.5 g, 17.5 pmol ,7 equiv), Cbz-L-Ala-(2-f-Bu)Tyr-OMe (compound 13) (8 mg, 17.5 pmol, 7 equiv), Ag ₂ C0 ₃ (6.0 mg, 22.5 pmol, 9 equiv), and Fe[TPP]CI (1.7 mg, 2.5 pmol, 1 equiv), in CDCI3 (600 pL) was stirred at room temperature for 24 hours before the ¹ H-NMR spectrum was recorded. The spectrum clearly shows that a ligand-exchange process took place, affording a mixture of complexes Fe[TPP][ compound 12] (compound 12a) and Fe[TPP][ compound 13] (compound 13a) (Figure 5C).

D) ¹ H-NMR spectrum was recorded after addition of HFIP (5 pL, 45 pmol, 18 equiv) to the above solution (C), which initiated a ligand-exchange process, affording a mixture of complexes Fe[TPP][ compound 12] (compound 12a), Fe[TPP][ compound 13] (compound 13a), and Fe[TPP][HFIP] (Figure 5D).

The experiment revealed that both A/-Boc-/V-Me-L-(2-f-Bu)Hpg-OBn (compound 12) and A/-Cbz-L-Ala-(2-f-Bu)Tyr-OMe (compound 13) bind unselectively to the Fe[TPP]CI metal center with and without the presence of HFIP.

4.2 Study of Oxidative cross-coupling between compound 33 and compound 9b (Approach A, step 2)

Products ratio of 1:2:1 (compound [33] ₂ : compound 33a : compoundlOb) was observed in the coupling of A/-Boc-L-(2-f-Bu)Tyr-L-Tyr-OBn (compound 33) with A/-Cbz-L-(2-f-Bu)Tyr-OMe (compound 9b) (Conditions: compound 33 (1 equiv), compound 9b (1 equiv), Fe[TPP]CI (1 mol %), UHP (1.2 equiv), HFIP, 20 minutes, Scheme 6 and Figure 6) . This result indicates similar reactivity between the two tyrosine units.

Scheme 6 5 Macrolactamization studies (Approach A, step 3)

5.1 Optimization

Macrolactamization of biaryl-bridged linear peptide compound 33a (Scheme 7) was studied under different conditions. The conditions and results of these studies are provided in Table S5.

Table S5: Different conditions for the macrolactamization of biaryl-bridged linear peptide 33a (selected examples)."

Scheme 7 entry coiiplin» reagents (2 equiv) additive (3 eqiii ) Solvent ( I in M ) yield «G 34

1 DLL HOBT DMF

2 HBTU Et ₃ N DMF

3 FDPP DIEA DMF

4 EDC DMAP DMF

"Reaction conditioned: a) 33a (25 mg, 0.0256 mmol, 1 equiv), Pd/C (10 mol%, 2.7 mg), ¾ (1 atm), EtOAc (5 mL), r.t., overnight b) 33b was added dropwise over 10 h, coupling reagent (2 equiv), additive (3 equiv), solvent (26 mL, 1 mM), r.t., overnight. ^b Isolated yield for two steps. ¾t 60°C. Abbreviations: DCC = Y.V- Dicyclohexylcarbodiimide, HOBt = 1 -Hydro xybenzotriazole, HBTU = (2-(l//-benzotriazol-l-yl)-l,l,3,3- tetramethyluronium hexafhiorophosphate, FDPP = Pentafluorophenyl 10, DIEA = V. V-Di isopropyl ethyl amine. EDC = l-Ethyl-3-(3-dimethylaminopropyl)carbodiimide, DMAP = 4-Dimethylaminopyridine, PyBOP = (benzotriazol-l-yloxy)tripyrrolidinophosphonium hexafhiorophosphate 6 Oxidative macrocyclization studies (Approach B, step 3)

6.1 Optimization

The oxidative macrocyclization of compound 17 (Scheme 8A) was investigated with metal complexes that are known to mediate a two-electron oxidation of phenols. Table S6 provides details of the complexes, reaction conditions and results.

As part of this study, the present inventors prepared a novel bis(p- hydroxo)dicopper(ll)[TMEDA] ₂ [TfO]2 complex (compound 20, Scheme 8B), which is a bench- stable reagent that can be easily prepared from compound 19 on a multigram scale and can be readily exploited for oxidative macrocyclization.

Scheme 8B

Indeed, when tripeptide compound 17 (1 equiv) and complex 20 (1 equiv) were mixed in HFIP (room temperature, N ₂ atmosphere, 18 hours), a highly selective intramolecular coupling took place, affording the pure arylomycin cyclic core compound 15 in 69% isolated yield (Scheme 8A). Without being bound by theory, the fact that complex 20, which differs from complex 19 only in the identity of their anions, showed completely inverted selectivity (Figure 7) implies that the anions play a key role in the coupling mechanism.

The crystal structure of complex 20 (Scheme 8B) showed that a triflate ion occupies the axial position of the two Cu(ll) atoms (Cu-0(3), 2.41 A). The weak interaction between the triflate ion and the two Cu(ll) atoms causes a distortion of the square planar geometry of complex 20 [the Cu(1)-0(1)-Cu(1)-0(2) torsion angle in 20 is 15.1°, while in the crystal structure of 19 it is 0.0° (Albov, D. V. et al. , Di-p-hydroxo-bis [(N, N, NT, N'-tetramethylethylenediamine) copper (II)] dichloride from X-ray powder data. Acta Crystallogr. 2004, 60 (8), 1193-1195)] and hence leads to a substantially shorter Cu- Cu (2.92 A) separation vis-a-vis that in complex 19 (3.03 A). Without being bound by theory, the present inventors postulated that the triflate ion in complex 20 ensures that the two copper atoms remain in close proximity throughout the reaction, thereby preventing the formation of monomeric copper intermediates that mediate oxidative coupling between two metal-bound phenoxyl radicals.

Table S6: Oxidative macrocyclization of A/-Boc-/\/-Me-L-(2-f-Bu)Hpg-Ala-(2-f-Bu)Tyr-OMe (17) under different conditions (selected examples) ⁹ (100)

18 [ Cu ⁿ (OH) «TEED A] ₂ Cl ₂ (100) AgOTf HFIP (10) n.d.

19 [ Cu ⁿ (OH) «TEED A] CE (100) HFIP (10) n.d.

20 [Cu ⁿ (OH).neo] ₂ Cl (100) AgOTf HFIP (10) n.r.

21 [Cu ⁿ (OH).neo] ₂ Cl (100) HFIP (10) n.r

24 C CI (100) AgOTf HFIP (10) Complex mixture

25 CuOTf ₂ (100) TMEDA HFIP (10) ^a Reaction conditions: 17 (1 equiv), metal catalyst, terminal oxidant or additive (2 equiv), N ₂ atm, solvent, r.t., overnight ^isolated yield ^C 1 equiv was used. ^d major product according to HPLC analysis. ^e n.d. = not determined prepared separately prior to the reaction. Abbreviations: N.R. = no reaction was observed. TEEDA = A ^, .A'.A'.A'-tctracth\ lcth\ lcncdiaminc. neo = neocuproine = 2,9- dimethylphenanthroline.

Reaction conditions:

Table S6, entries 4-6:

A solution of complex 19 or 20 (0.01-0.1 mmol) and A/-Boc-/V-Me-L-(2-M3u)Hpg-L-Ala-L-(2-f- Bu)Tyr-OMe (compound 17) (64.6 mg, 0.1 mmol, 1 equiv) in HFIP (0.01 M) was stirred for 24 hours at room temperature under oxygen. Upon 24 hours, the crude residue was purified by column chromatography (EtOAc/hexane 60:40) affording compound 18 and trace of compound 15.

Table S6, entries 7-9, 19 and 21 :

A solution of copper source (100 mol %) and A/-Boc-/V-Me-L-(2-f-Bu)Hpg-L-Ala-L-(2-f-Bu)Tyr-OMe (compound 17) (1 equiv) in solvent (10 mM) was stirred for 24 hours at room temperature under nitrogen. The reaction was monitored by HPLC.

Table S6, entries 10-11:

A solution of complex 19 (22.3 mg or 44.6 mg, 0.5 mmol or 0.1 mmol) and AgOTf (25.7 mg or 51.4 mg, 0.1 mmol or 0.2 mmol) in HFIP (0.01 M) was stirred for 2 hours at room temperature under nitrogen followed by addition of compound 17 (64.6 mg, 0.1 mmol). The mixture was stirred for additional 18 hours. Upon reaction completion, an aqueous solution of saturated Na ₂ EDTA was added to the reaction flask and stirred for 1 hour. The solution was filtered through a celite bed, diluted with brine and extracted with EtOAc (2x20 ml_). The combined organic phase was dried over Na ₂ S0 ₄ , the volatiles were removed under reduced pressure and the crude residue was purified by silica-gel column chromatography (ethyl acetate/hexane 40:60) affording compound 15 (32 g or 45 g, 50% or 70% yield respectively) as a yellow solid.

Table S6, entries 12-18, 20 and 24:

A solution of complex copper source (50-100 mol %) and Ag source (1-2 equiv) in solvent (10 mM) was stirred for 2 hours at room temperature under nitrogen, then compound 17 (1 equiv) was added to the mixture. The reaction was monitored by HPLC.

Table S6, entry 22:

A solution of complex 20 (72.5 g, 0.1 mmol) in HFIP (0.01 M) was stirred at ambient conditions, then compound 15 (64.1 g, 0.1 mmol) was added and the mixture was stirred for additional 18 h. Upon reaction completion, an aqueous solution of saturated Na ₂ EDTA was added to the reaction flask and stirred for 1 h. The solution was filtered through a celite bed, diluted with brine and extracted with EtOAc (2x20 ml_). The combined organic phase was dried over Na ₂ S0 ₄ , the volatiles were removed under reduced pressure and the crude residue was purified by silica-gel column chromatography (ethyl acetate/hexane 40:60) affording compound 21 (44.3 g, 69% yield) as a yellow solid.

7 Experimental

7.1 Preparation and characterization of compound 19, compound 20 and Co[salen]

A. Preparation and characterization of [Cu"(OH) *TMEDA]2[TfO]2 (compound 20)

Me ₂ H Me ₂ Compound 20: A solution of [Cu"(OH) «TMEDA] ₂ CI ₂ (19) (44.6 g,

[TfO ] ₂ 0.3 mmol, 1 equiv) and AgOTf (153.0 g, 0.6 mmol, 2 equiv) in HFIP (0.01 M) was stirred over night at room temperature under oxygen

Compound 20 atmosphere. The solution was filtered through a celite bed to remove insoluble AgCI salt. The solvent was removed under reduced pressure affording compound 20 which was dried under high vacuum for several hours (200.2 g, 91 % yield). Single crystals were obtained by slow evaporation of a solution of compound 20 in a 1:1 mixture of DCE:MeOH and characterized using XRD, as shown in Figure 8.

B. Preparation of [Cull(OH) *TMEDA]2[CI]2 (compound 19):

To a solution of N,N,N',N'-Tetramethylethylenediamine (TMEDA) (3 mmol) in 6 ml. of 95% aqueous ethanol, CuCI (3 mmol) was added. The mixture was stirred vigorously at room temperature overnight under dioxygen atmosphere. The resulting precipitates was filtered and washed with small amount of 95% aq. ethanol. The precipitate was dried under high vacuum affording [Cu"(OH) «TMEDA] ₂ [CI] ₂ as dark purple solid.

C. Preparation of Co[salen] :

Co[salen] was prepared according to a procedure described in : J. Org. Chem. 2019, 84, 12, 7950-7960

1. A solution of 2,4-di-fe/f-butyl phenol (1 equiv), MgCI2 (1.5 equiv), paraformaldehyde (7 equiv), Et ₃ N (7 equiv) in THF (0.2 M) was refluxed until full consumption of the phenol (as indicated by TLC). The mixture was quenched with HCI (1 M) and extracted with ethyl acetate (X3). The combined organic layers were washed with brine, dried with MgS0 ₄ and evaporated under reduced pressure. The crude residue was purified by column chromatography (silica gel 40-60 mΐti) to obtain 3,5-di-tert-butyl-2-hydroxybenzaldehyde.

2. A solution of 1 ,2-diphenylethane-1, 2-diamine (1 equiv), 3,5-di-tert-butyl-2- hydroxybenzaldehyde (2.1 equiv) in EtOH (0.2 M) was stirred at room temperature until full consumption of 1 ,2-diphenylethane-1 , 2-diamine. After the consumption of the 1 ,2- diphenylethane-1, 2-diamine, Co(Ac) ₂ (1.1 equiv) was added to the solution and the reaction was stirred overnight. The precipitant was filtered under vacuum and washed with cold EtOH to obtain the desired Co[salen] complex.

7.2 General synthetic procedures

A. Peptide coupling

/V-protected amino acid (1 equiv) and amino acid ester (1 equiv) were dissolved in MeCN/DMF (4:1) solution (0.1 M). To this solution was added HOBt (1 equiv) and Et ₃ N (3.3 equiv). After stirring for 5 minutes, it was cooled to 0°C, and EDC (1.5 equiv) was added at once. The reaction mixture was allowed to warm to room temperature and stirred for 18 hours. Upon completion, the mixture was partitioned between EtOAc and H2O and extracted with EtOAc (* 3). The organic layers were combined, washed with NaHC0 ₃ (aq.), NH ₄ CI (aq.), brine (aq.), dried over Na ₂ S0 ₄ and concentrated under reduced pressure. The residue was purified by column chromatography.

B. Peptide coupling

Amino acid ester (1 equiv) was dissolved in DMF (0.5 M). The amino acid ester was obtained by neutralization with saturated Na ₂ C0 ₃ from its hydrochloride salt and subsequent extraction with EtOAc. /V-protected amino acid (1.25 equiv) were added to the mixture under 0°C, followed by HOBt (1.4 equiv) and DCC (1.4 equiv). The reaction mixture was allowed to warm to room temperature and stirred overnight. DCU was filtrated, and the filtrate was evaporated under reduced pressure. The residue was dissolved in EtOAc, washed successively with cold 1 M HCI solution, NaHC0 ₃ (aq.), brine (aq.), and dried over MgS04. The residue was purified by column chromatography.

C. Oxidative coupling of activated L-tyrosine

UHP was added to a stirred solution of (2-f-Bu)tyrosine derivative and Fe[TPP]CI in HFIP. The mixture was stirred at room temperature for 15-30 minutes. Upon completion (as indicated by HPLC analysis) ^* , the solvent was removed under reduced pressure and the residue was purified by column chromatography.

*HPLC analysis is required since for most cases the retention time of the starting materials and homocoupling products are similar. C-l. Oxidative Coupling - Alternative Procedures

Alternative Procedure 1 : DTBP (1.5 eq.) was added to a stirred solution of compound of Formula A, compound of Formula B, FeCI ₃ (anhydrous 98%) in HFIP. The mixture was stirred at room temperature for 2 hours. Upon completion, the solvent was removed under reduced pressure and the residue was purified by column chromatography.

Alternative Procedure 2: Solution of compound of Formula A, compound of Formula B, [Cu"(OH) «TMEDA] ₂ [CI] ₂ (2 mol %) in HFIP was stirred at room temperature under 0 ₂ atmosphere for 24 hours. Upon completion, the solvent was removed under reduced pressure and the residue was purified by column chromatography.

Alternative Procedure 3: Solution of compound of Formula A, compound of Formula B, Co[salen] (1 mol %) in HFIP was stirred at room temperature under 0 ₂ atmosphere for 24 hours. Upon completion, the solvent was removed under reduced pressure and the residue was purified by column chromatography.

D. Macrolactamization

A mixture of 2,2'-(di-f-Bu)di-tyrosine derivatives (1 equiv) and 10 mol% Pd/C in HFIP, MeOH or EtOH (0.1 M), was purged with Argon for 1 hour. Then the mixture was stirred under H ₂ atmosphere (1 atm) for 2-6 hours. Upon completion the catalyst was filtered through celite bed and the filtrate was evaporated under reduced pressure. The residue was dissolved in MeCN (4.3 mM) and was added dropwise over a 10 hours period to a stirred solution of PyBOP (2 equiv) and DMAP (3 equiv) in MeCN (0.9 mM). The mixture was allowed to stir for additional 3 hours. The solvent was removed under reduced pressure and the residue was suspended in H ₂ 0 and extracted with EtOAc (* 3). The organic layers were combined, washed with NaHC0 ₃ (aq.), brine (aq.), dried over Na ₂ S0 ₄ , and concentrated under reduced pressure. The residue was purified by column chromatography.

E. Dealkylation of ferf-butyl in biaryl-bridged cyclic-peptides

Trifluoromethanesulfonic acid was added dropwise to a stirred solution of 2,2’-(di-f-Bu)di- tyrosine cyclic peptides in HFIP (0.1M) at 0°C. The mixture was allowed to warm to room temperature and stirred overnight. Cs ₂ C0 ₃ was added to the mixture at 0°C and the reaction stirred for additional 20 minutes at room temperature. The solvent was removed under reduced pressure and the residue was purified by column chromatography.

F. Oxidative macrocyclization

Linear tripeptide (1 equiv) was added to a stirred solution of complex 20 (1 equiv) in HFIP (0.01 M) at room temperature, under nitrogen atmosphere and the mixture was stirred for additional 18 hours at room temperature. Upon completion, Na ₂ EDTA (aq.) was added to the reaction flask and stirred for 1 hour. The solution was filtered through celite bed, diluted with brine (aq.) and extracted with EtOAc (2 ^c 20 mL). The combined organic phase was dried over Na ₂ S0 ₄ , the volatiles were removed under reduced pressure and the crude residue was purified by silica- gel column chromatography.

7.3 Compound preparation and characterization

Compound S8a: Thionyl chloride (36 ml_, 496 mmol, 1.8 equiv) was added dropwise to a solution of L-tyrosine (50 g, 276 mmol) in anhydrous MeOH (900 ml_, 22 mol) at 0 °C under argon atmosphere. When half amount Hci of thionyl chloride was added, the solution became clear. The reaction mixture w ^{as allowed to rea} °h room temperature and stirred overnight. Upon completion the solvent was evaporated under reduced pressure and the

Compound S8a resulting salt washed with Et ₂ 0 (2 ^c 50 ml.) affording compound S8a as a white solid (63 g, 272 mmol, 98% yield).

Compound 9: Methanesulfonic acid (70 ml_, 1.08 mol, 5 equiv) was added dropwise to a mixture of L-tyrosine methyl ester hydrochloride (compound S8a) (50 g, 216 mmol) and fe/f-butylchloride (118 mL, 1.08 mol, 5 equiv). The mixture w ^as stirred for 12 hours at 50 °C. Upon completion the mixture was poured slowly ' ^nto ' ^{ce co} ' ^d NaHC0 ₃ (aq.) solution while stirring. Once pH 8 was reached, the

Compound 9 ^m ' ^{xture was} extracted with EtOAc (3 ^c 400 mL), washed with brine (aq.), dried over Na ₂ S0 ₄ and concentrated under reduced pressure, affording compound 9. The resulting residue was used without further purification. Compound 9a: Di-fe/f-butyl dicarbonate (51 g, 237 mmol, 1.1 equiv) w ^as added to a stirred solution of Et ₃ N (45 mL, 322 mmol, 1.5 equiv) and methyl- 3-fe/f-butyltyrosinate (compound 9) (216 mmol, 1 equiv) in dry MeOH (1.3 L) under nitrogen atmosphere at 0°C. The mixture was allowed to warm to room temperature and stirred for 18 hours. Upon completion, the solvent was evaporated under reduced pressure and the residue was partitioned between

Compound 9a

1M HCI (aq.) and EtOAc and extracted with EtOAc (3 ^c 150 mL). The organic layers were combined, washed with brine (aq.), dried over MgS0 ₄ and concentrated under reduced pressure. The resulting residue was purified by column chromatography affording compound 9a (EtOAc:hexane 40:60, 54g, 71% yield for 2 steps) as a white solid.

Characterization of compound 9a: [a]¾ ² = +10 (c = 0.025, EtOH); Ή NMR (400 MHz, Chloroform-d) d 6.95 (d, J = 2.2 Hz, 1H), 6.79 (dd, J = 8.0, 2.2 Hz, 1H), 6.57 (d, J = 8.0 Hz, 1H), 5.63 (s, 1H), 5.01 (d, J = 8.5 Hz, 1H), 4.56 (dt, J = 8.5, 5.7 Hz, 1H), 3.71 (s, 3H), 3.16 - 2.83 (m, 2H), 1.43 (s, 9H), 1.38 (s, 9H); ¹³ C NMR (101 MHz, CDC13) d 172.71, 155.25, 153.66, 136.09, 128.04, 127.53, 127.10, 116.61, 80.08, 54.55, 52.26, 37.74, 34.50, 29.54, 28.34; HRMS (ESI): m/z calcd for C ₁₉ H ₂₉ NO ₅ [M+Na]+ 374.1938, found 374.1926 Compound 9b: A solution of Na ₂ C0 ₃ (23 g, 216 mmol, 1 equiv) in H ₂ 0

(125 mL) was added to a stirring suspension of crude methyl-3-f-butyltyrosinate (compound 9) (216 mmol, 1 equiv) in THF (800 mL) at 25°C. The mixture was then cooled to 0 °C, and benzyl chloroformate (31 mL, 216 mmol, 1.0 equiv) f ^ollowed hy Na ₂ C0 ₃ (2.0 M in H ₂ 0, 100 mL) were added. The mixture was stirred Compound 9b f° ^r hours at room temperature. Upon completion, the THF was evaporated and the aqueous layer was extracted with EtOAc (x 3). The organic layers were combined, dried over MgS0 ₄ and concentrated. The resulting yellow solid was purified by column chromatography affording compound 9b (EtOAc: hexane 35:65, 59 g, 70% yield for 2 steps) as a white solid.

Characterization of compound 9b: [a]¾ ² = +4 (c = 0.025, EtOH); Ή NMR (400 MHz, Chloroform-d) d 7.39 - 7.28 (m, 5H), 6.96 (d, J = 2.3 Hz, 1H), 6.77 (dd, 1H), 6.55 (d, J = 8.0 Hz, 1H), 5.81 (s, 1H), 5.30 (d, J = 8.3 Hz, 1H), 5.11 (s, 2H), 4.64 (dd, J = 10.0, 4.2 Hz, 1H), 3.73 (s, 3H), 3.04 (d, J = 5.8, 1.9 Hz, 2H), 1.37 (s, 9H); ¹³ C NMR (101 MHz, CDC13) d 172.41, 155.88, 153.84, 136.23, 136.13, 128.57, 128.25, 128.13, 127.97, 127.52, 126.73, 116.67, 67.13, 55.77, 54.99, 52.43, 37.69, 34.51, 29.53; HRMS (ESI): m/z calcd for C ₂₂ H ₂₇ N0 ₅ [M+Na]+ 408.1781, found 408.1768. Compound 9c: Solution of NaOH (0.8 g in 20 ml. H ₂ 0, 3.0 equiv, 1 M) was added to a solution of compound 9a (2.7 g, 6.9 mmol) in MeOH (0.1 M) and the reaction was stirred for 6 hours. Upon completion, MeOH was evaporated under reduced pressure. The residue was diluted with H ₂ 0 and washed with Et ₂ 0 (x 2). The aqueous layer was acidified with 1 N HCI (aq.) until pH = 2-3 was reached and extracted with ethyl acetate (x

Compound 9c 3). The organic layers were combined, washed with brine (aq.), dried over Na ₂ S0 ₄ and concentrated under reduced pressure, affording compound 9c as a white solid (2.2 g, 6.5 mmol, 94% yield).

O Compound 9d: Solution of NaOH (1.6 g in 40 ml. H ₂ 0, 3.0 equiv, M) _was added to a solution of compound 9b (5 g, 13 mmol) in MeOH (0.1 M) and the reaction was stirred for 6 hours. Upon completion, MeOH was removed under reduced pressure. The residue was diluted with H ₂ 0 and f-Bu washed with diethyl ether (x 2). The aqueous layer was acidified with 1 N HCI (aq.) until pH = 2-3 was reached and extracted with ethyl acetate (x

Compound 9d 3). The organic layers were combined, washed with brine (aq.), dried over Na ₂ S0 ₄ and concentrated under reduced pressure affording compound 9d as a white solid (4.5 g, 12 mmol, 94% yield).

Compound 10a (EtOAc:hexane 40:60, 1.96 g, 98% yield) as yellow solid.

Characterization of compound 10a: [a]¾ ⁴ = 0 (c = 0.025, MeOH); *H NMR (500 MHz, Chloroform-d) d 7.08 (s, 1H), 7.04 (s, 1H), 6.91 (s, 1H), 6.76 (s, 1H), 5.83 (s, 1H), 5.36 (s, 1H), 5.10 (d, J = 8.6 Hz, 1H), 5.02 (d, J = 8.4 Hz, 1H), 4.72- 4.40 (m, 2H), 3.75 (s, 6H), 3.24 - 2.93 (m, 3H), 2.92- 2.75 (m, 1H), 1.43 (s, 27H), 1.35 (s, 9H); ¹³ C NMR (126 MHz, CDC13) d 172.55, 172.42, 155.10, 154.94, 151.78, 151.54, 137.54, 137.07, 129.21, 129.03, 128.45, 127.39, 127.22, 122.62, 122.11, 79.94, 54.61, 54.45, 52.35, 38.66, 37.63, 34.99, 29.65, 29.54, 28.31, 28.26; HRMS (ESI): m/z calcd for C ₃₈ H ₅₆ N ₂ O _IO [M+Na]+ 723.3827, found 723.3818.

Compound 10b (EtOAc:hexane 40:60, 1.94 g, 97% yield) as yellow solid.

Characterization of compound 10b: [a]¾ ⁴ = -2 (c = 0.025, MeOH); Ή NMR (400 MHz, Chloroform- d) d 7.42 - 7.27 (m, 10H), 7.05 (s, 2H), 6.88 (s, 1H), 6.74 (s, 1H), 5.65 (s, 1H), 5.38- 5.20 (m, 3H), 5.11 (s, 2H), 5.01 (dd, 2H), 4.72 - 4.54 (m, 2H), 3.76 (s, 3H), 3.74 (s, 3H), 3.22 - 2.95 (m, 3H), 2.95- 2.71 (m, 1H), 1.40 (s, 9H), 1.39 (s, 9H); ¹³ C NMR (101 MHz, CDC13) d 172.21, 172.07, 155.58, 151.64, 137.67, 137.32, 136.13, 129.14, 128.99, 128.55, 128.20, 128.12, 128.03, 127.25, 122.75, 122.12, 77.37, 77.05, 76.73, 67.02, 55.16, 54.93, 52.51, 38.48, 37.69, 34.99, 29.62, 29.52; HRMS (ESI): m/z calcd for C ₄₄ H ₅₂ N ₂ O ₁₀ [M+Na]+ 791.3514, found 791.3541.

C d 11 f 10 C d 10 70 0 0 1 , .

Compound it to _{warm to room} temperature and stirred overnight. Cs ₂ C0 ₃ (325 mg, 1 mmol, 10 equiv) was added to the mixture at 0°C and the reaction was stirred for additional 20 minutes at room temperature. The solvent was removed under reduced pressure and the residue was purified by column chromatography affording compound 11 (MeOH:DCM 10:90, 36 mg, 92% yield) as yellow solid.

Compound 11 from 10b: Compound 10b (120.0 mg, 0.16 mmol, 1 equiv) and Pd/C (5 mol%) were dissolved in MeOH (5 mL) and stirred under H ₂ atmosphere (1 atm) for 2 hours at room temperature. Upon completion, the mixture was filtered through celite bed and the residue was concentrated under vacuum. The residue was dissolved in HFIP (1.5 ml.) and cooled to 0°C. Trifluoromethanesulfonic acid (137 pl_, 1.6 mmol, 10 equiv) was added dropwise. The mixture was allowed to warm to room temperature and stirred overnight. Cs ₂ C0 ₃ (500 mg, 1.6 mmol, 10 equiv) was added to the mixture at 0°C and the reaction was stirred for additional 20 minutes at room temperature. The solvent was removed under reduced pressure and the residue was purified by column chromatography affording compound 11 (MeOH:DCM 10:90, 55 mg, 90% yield) as yellow solid.

Characterization of compound 11: [a]¾ ² = -2 (c = 0.025, MeOH); 'H NMR (400 MHz, DMSO- d6) d 6.93 (s, 2H), 6.91 (s, 1H), 6.91 (s, 1H), 6.78 (s, 1H), 6.76 (s, 1H), 4.37 (s, 4H), 3.59 (s, 6H), 3.56 (t, J = 6.5 Hz, 2H), 2.80 (dd, J = 13.5, 6.1 Hz, 2H), 2.71 (dd, J = 13.5, 6.8 Hz, 2H); ¹³ C NMR (101 MHz, DMSO) d 175.63, 154.06, 132.57, 129.21, 127.77, 126.36, 116.41, 56.28, 51.87, 40.27; HRMS (ESI): m/z calcd for C20H24N2O6 [M+H]+ 389.1707, found 389.1696.

7.4 Synthesis of biaryl-cyclic peptides according to Approach A

7.4.1 Arylomycin cyclic core 16 - Synthetic scheme, compound preparation and characterization

Scheme 9

Compound 12a: Methanesulfonic acid (15.5 ml, 0.24 mol, 5 equiv) was added dropwise to a stirred solution of L-4-Hydroxyphenylglycine (8 g, 47.9 mmol, 1 equiv) in tert- Butanol (30 ml.) and the solution heated to 60°C and stirred for 3 days. Upon completion H ₂ 0 (70 ml.) was added, followed by addition of NaHCOa at 0°C while stirring until pH=8 was reached. THF (70 ml.)

Compound 12a and NaOH (3.8 g, 95.8 mmol, 2 equiv) was then added to the mixture and stirred at room temperature until all the solid dissolved. Di-fe/f-butyl dicarbonate (13.6 gr, 62.3 mmol, 1.3 equiv) was added and the solution stirred overnight. THF was removed under reduced pressure and citric acid was added until pH = 4 was reached. The solution was extracted with EtOAc (x 2). The organic layers were combined, washed with brine (aq.), dried with Na ₂ S0 ₄ and concentrated under reduced pressure to produce white solid that was used without further purification.

Compound 12b: A/-Boc-L-(2-f-Bu)Hpg-OH (compound 12a) (47.9 mmol, 1 equiv) was dissolved in toluene (700 ml.) followed by addition of paraformaldehyde (7 g, 239.5 mmol, 5 equiv) and p-toluenesulfonic acid (825 mg, 4.8 mmol, 0.1 eq.). The mixture was refluxed in a Dean-Stark apparatus for 1 hour. The solvent was removed under reduced pressure, and the residue was taken up in EtOAc and washed twice with NaHC0 ₃ (aq.). The organic

Compound 12b layer was dried with Na ₂ S0 ₄ and concentrated under reduced pressure. The residue was purified by flash column chromatography affording compound 12b (EtOAc:hexane 15:85, 9.7 gr, 60% yield for 3 steps) as white foam.

Characterization of compound 12b: [a]¾ ³ = -72 (c = 0.025, MeOH); Ή NMR (500 MHz, Chloroform-

< d 7.19 (d, J= 2.3 Hz, 1H), 6.96 (d, J= 7.4 Hz, 1H), 6.58 (s, 1H), 5.63 (s, 2H), 5.43 (d, J= 4.6 Hz, 1H), 5.13 (s, 1H), 1.40 (s, 18H); ¹³ C NMR (126 MHz, CDC1 ₃ ) d 171.69, 154.96, 136.75, 125.55, 124.97, 116.94, 82.27, 78.25, 58.62, 34.63, 29.38, 28.17; HRMS (ESI): m/z calcd for Ci ₈ H ₂₅ N0 ₅ [M+Na]+ 358.1625, found 358.1621.

Compound 12c: Compound 12b (9.6 g, 28.7 mmol, 1 equiv) was dissolved in DCM (40 ml_). The reaction was cooled to 0°C and placed under nitrogen atmosphere. Triethylsilane (18.5 ml_, 114.6 mmol, 4 equiv) was added. TFA (40 ml.) was added dropwise and the solution warmed to room temperature and stirred overnight. The solvent was removed under air stream

Compound 12c at ~35°C. The resulting residue was suspended in H ₂ 0 (80 ml.) and cooled to 0°C. Solid NaHC0 ₃ was added until pH = 7-8 was reached. THF (80 ml.) and NaOH (2.3 gr, 57.3 mmol, 2 equiv) was added. Di-fe/f-butyl dicarbonate (9.4 g, 43 mmol, 1.5 equiv) was added and the mixture was stirred at room temperature overnight. Upon completion, THF was removed under reduced pressure. The aqueous layer was washed twice with hexane. The aqueous layer acidified to pH = 2 using 4 N HCI (aq.) and extracted with DCM (x 2). The organic layers were combined, washed with brine (aq.), dried over Na ₂ S0 ₄ and concentrated under reduced pressure to afford compound 12c as white powder (7.87 gr, 81% yield). Compound 12: Benzyl bromide (3.5 ml, 28.0 mmol, 1.2 eq.) was added to a solution of A/-Boc-/V-Me-L-(2-f-Bu)Hpg-OH (compound 12c) (7.9 gr, 23.3 mmol, 1 eq.) and NaHC0 ₃ (2.35 gr, 28.0 mmol, 1.2 eq.) in DMF (50 ml) at 0°C. The mixture stirred at 0°C for 2 hours and then at room temperature overnight. H ₂ 0 was added and the mixture extracted twice with EtOAc. The

Compound 12 organic layers were combined, washed with brine, dried over Na ₂ S04 and concentrated under reduced pressure. The residue was purified by column chromatography affording compound 12 (EtOAc:hexane 20:80, 7.3 gr, 74% yield) as white foam. Characterization of compound 12: [a]¾ ³ = +36 (c = 0.025, MeOH); Ή NMR (500 MHz, Chloroform- d) d 7.32 (s, 5H), 7.06 (d, J= 2.3 Hz, 1H), 6.86 (dd, J= 8.2, 2.3 Hz, 1H), 6.64 (d, J= 8.1 Hz, 1H), 5.72 (bs, 1H), 5.20 (d, 2H), 2.66 (s, 3H), 1.48 (s, 9H), 1.35 (s, 9H); ¹³ C NMR (126 MHz, CDC ) d 171.47, 154.66, 136.50, 135.56, 128.54, 128.35, 128.03, 127.58, 116.55, 80.57, 66.81, 62.96, 61.85, 34.58, 31.05, 29.41, 28.40; HRMS (ESI): m/z calcd for C ₂₅ H ₃₃ N0 ₅ [M+Na]+ 450.2266, found 450.2251.

Compound 13 affording compound 13 (EtOAc:hexane 40:60, 3.1 g, 53% yield) as a white solid.

Characterization of compound 13: [a]¾ ³ = +6 (c = 0.025, MeOH); Ή NMR (400 MHz, Chlorolbrm-c/) d 7.40 - 7.27 (m, 4H), 6.92 (s, 1H), 6.76 (d, J= 7.6 Hz, 1H), 6.67 - 6.51 (m, 2H), 6.38 (s, 1H), 5.49 (d, J = 7.7 Hz, 1H), 5.08 (dd, J= 12.2 Hz, 2H), 4.80 (dd, J= 9.1, 4.5 Hz, 1H), 4.26 (t, J= 7.1 Hz, 1H), 3.70 (s, 3H), 3.03 (dd, J= 5.8, 2.2 Hz, 2H), 1.35 (s, 9H), 1.32 (d, J= 7.1 Hz, 3H); ¹³ C NMR (101 MHz, CDC1 ) d 172.13, 171.97, 155.97, 154.09, 136.29, 136.10, 128.58, 128.25, 128.13, 127.80, 127.62, 126.51, 116.62, 67.14, 53.46, 52.44, 50.53, 37.31, 34.51, 29.52, 18.74; HRMS (ESI): m/z calcd for C25H32N2O6 [M+H]+ 457.2333, found 457.2336.

Compound 14 room temperature for 20 minutes. The addition of compound 13 and m- CPBA was repeated 3 more times (total amount of compound 13: 1.87 gr, 4.1 mmol, 1 equiv; total amount of rn-CPBA: 1.41 g, 8.2 mmol, 2 equiv). After the last addition, the mixture was stirred for additional 1 hour. At the end of the reaction, the solvent was evaporated under reduced pressure. The residue was suspended in NaHC0 ₃ (aq.) and extracted with EtOAc (* 2). The organic layers were combined, washed with brine (aq.), dried over Na ₂ S0 ₄ and concentrated under reduced pressure. The residue was purified by column chromatography affording compound 14 (EtOAc:hexane 30:70, 1.72 g, 48% yield) as yellow solid.

Characterization of compound 14: [a]¾ ⁴ = +14 (c = 0.025, MeOH); *H NMR (500 MHz, DMSO-ifc, T = 35 OK) d 8.20 (s, 1H), 7.96 (d, J= 8.1 Hz, 1H), 7.41 - 7.20 (m, 10H), 7.13 (dd, J= 4.5, 2.3 Hz, 2H), 7.02 (d, J= 2.3 Hz, 1H), 6.88 (d, J= 2.2 Hz, 1H), 5.76 (s, 1H), 5.31 - 5.18 (m, 2H), 5.06 - 4.96 (m, 2H), 4.58 (dd, J= 7.6 Hz, 1H), 4.12 (dq, J= 7.2 Hz, 1H), 3.63 (s, 3H), 3.02 (dd, J= 14.1, 6.0 Hz, 1H), 2.95 (dd, J = 14.0, 7.7 Hz, 1H), 2.70 (s, 3H), 1.43 (s, 9H), 1.42 (s, 9H), 1.39 (s, 9H), 1.21 (d, J= 7. 1 Hz, 3H); ¹³ C NMR (126 MHz, DMSO, T= 350K) d 173.16, 172.47, 171.04, 155.93, 152.47, 151.07, 139.54, 138.97, 137.44, 136.21, 130.93, 129.35, 128.87, 128.77, 128.62, 128.24, 128.21, 127.53, 126.73, 80.10, 66.70, 65.81, 62.62, 54.14, 52.28, 50.37, 35.15, 32.12, 30.32, 30.14, 28.39, 18.75; HRMS (ESI): m/z calcd for C^NiOii [M+Na]+ 904.4355, found 904.4343. chromatography, affording compound 15 (EtOAc/hexane 40:60,

Compound 15 126 mg, 70% yield for 2 steps) as a white solid. Characterization of compound 15: [a]¾ ⁴ = +26 (c = 0.025, MeOH); *H NMR (500 MHz, DMSO-d6, T = 360K) d 9.08 (s, 1H), 8.78 (d, J = 5.7 Hz, 1H), 8.17 (d, J = 8.9 Hz, 1H), 7.11 (s, 1H), 7.08 (s, 1H), 6.84 (s, 1H), 6.82 (s, 1H), 5.91 (s, 1H), 4.87 - 4.69 (m, 2H), 3.71 (s, 3H), 3.26 (dd, J = 16.9, 2.6 Hz, 1H), 3.07 (dd, J = 16.8, 11.6 Hz, 1H), 2.59 (s, 3H), 1.46 (s, 9H), 1.44 (s, 9H), 1.43 (s, 9H), 1.23 (d, J = 6.7 Hz, 3H); ¹³ C NMR (126 MHz, DMSO, T = 360K) d 172.66, 172.33, 170.72, 151.29, 150.24, 140.20, 140.08, 132.45, 130.70, 129.96, 129.47, 126.75, 126.42, 79.46, 62.13, 52.50, 51.59, 48.08, 35.16, 35.10, 33.99, 32.16, 30.59, 30.48, 28.68, 19.29; HRMS (ESI): m/z calcd for C35H49N3O8 [M+Na]+ 662.3412, found 662.3408

Com ound 16: C clic e tide com ound 15 (194 0 3 compoun ( e : : , mg, y e ) as w te

Compound 16 solid. Compound 16 exists as a single atropoisomerwith an S _A -axial configuration, which is in agreement with the arylomycin absolute configuration.

Characterization of compound 16: [a]¾ ³ = +4 (c = 0.025, EtOH); *H NMR (500 MHz, DMSO-rfc) d 9.20 (d, J= 8.4 Hz, 1H), 8.76 (d, J= 9.1 Hz, 1H), 7.27 (dd, J= 8.4, 2.4 Hz, 1H), 7.03 - 6.97 (m, 2H), 6.94 (d, J = 2.3 Hz, 1H), 6.77 (d, J= 8.3 Hz, 1H), 6.74 (d, J= 8.0 Hz, 1H), 4.92 - 4.81 (m, 1H), 4.59 (ddd, J= 10.9, 8.3, 2.0 Hz, 1H), 4.52 (s, 1H), 3.70 (s, 3H), 3.05 (d,J= 14.3 Hz, 1H), 2.94 (dd,J= 15.7, 11.5 Hz, 1H), 2.37 (s, 3H), 1.24 (d, J= 6.7 Hz, 3H); ¹³ C NMR (126 MHz, DMSO) d 172.48, 172.38, 171.37, 156.07, 154.76, 131.97, 131.23, 129.23, 128.59, 127.91, 127.85, 127.47, 127.25, 117.00, 116.76, 64.45, 52.85, 52.79, 48.29, 34.23, 33.94, 19.68; HRMS (ESI): m/z calcd for C22H25N3O6 [M+H]+ 428.1816, found 428.1805.

7.4.2 Biaryl-bridged cyclic peptide compound 32 - Synthetic scheme (Scheme 10), compound preparation and characterization

Scheme 10

/—-i Compound S31: Thionyl chloride (5.7 ml_, 78 mmol, 1.8 equiv) was

N ^L oo ₂ Bh added dropwise to a solution of L-proline (5 g, 43 mmol) in benzyl alcohol HOI H

Compo nd S31 (200 mL) at 0 °C under argon atmosphere. The reaction mixture was heated to 95 °C and stirred for 6 hours. Upon completion, the mixture was cooled to room temperature and diluted with Et ₂ 0 until white solid was precipitated. The mixture was stirred for additional 16 hours at room temperature. The precipitate was filtered, washed with Et ₂ 0 and dried, affording compound S31 as a white solid (9.4 g, 90% yield).

Compound 31: Compound S31 (1.53 g, 6.31 mmol, 1 equiv), was reacted with A/-Boc-L-(2-t-Bu)Tyr-OH 9c (2.13 g, 6.31 mmol, 1 equiv) according to general procedure A for peptide coupling, using HOBt (850 mg, 6.31 mmol, 1 equiv), EDC (1.82 g, 9.46 mmol, 1.5 equiv) and Et ₃ N (2.7 mL, 19 mmol, 3.3 equiv). The crude residue was purified by

Compound 31 column chromatography affording compound 31 (EtOAc:hexane 40:60, 2.71 g, 82% yield) as a white solid.

Characterization of compound 31: [«]¾ ³ = -14 (c = 0.025, MeOH); *H NMR (500 MHz, DMSO-rfc) d 9.11 (s, 1H), 7.40 - 7.27 (m, 4H), 7.05 (d, J= 6.4 Hz, 1H), 7.04 (s, 1H), 6.87 (dd, J= 8.1, 2.2 Hz, 1H), 6.65 (d, J= 8.1 Hz, 1H), 5.12 (s, 2H), 4.40 (dd, J= 8.6, 4.7 Hz, 1H), 4.34 - 4.24 (m, 1H), 3.66 (dt, J= 9.6, 6.9 Hz, 1H), 3.56 - 3.42 (m, 1H), 2.77 - 2.54 (m, 2H), 2.26 - 2.13 (m, 1H), 1.97 - 1.88 (m, 2H), 1.84 (ddd, J = 12.7, 6.3, 4.7 Hz, 1H), 1.33 (s, 9H), 1.31 (s, 9H); ¹³ C NMR (126 MHz, DMSO) d 172.12, 171.14, 155.69,

154.71, 136.46, 135.11, 128.89, 128.50, 128.30, 128.29, 128.26, 128.02, 127.93, 127.82, 127.72, 127.65, 116.24, 78.37, 66.27, 59.10, 54.26, 46.84, 36.29, 34.66, 29.84, 28.99, 28.67, 25.16 HRMS (ESI): m/z calcd for C30H40N2O6 [M+H]+ 525.2959, found 525.2968.

Com ound 31a: S nthesized accordin to eneral purified by column chromatography, affording compound 31a (EtOAchexane 20:80, 290 mg, 68% yield) as yellow solid.

Characterization of compound 31a: [a]¾ ³ = -12 (c = 0.025, MeOH); *H NMR (500 MHz, DMSO-ί/b _, T = 340K) d 7.59 - 7.23 (m, 10H), 7.19 (d, J= 2.2 Hz, 1H), 7.12 (d, J= 2.2 Hz, 1H), 7.02 - 6.95 (m, 2H), 5.15 - 5.04 (m, 2H), 5.01 (s, 2H), 4.53 - 4.39 (m, 2H), 4.36 - 4.27 (m, 1H), 3.74 - 3.67 (m, 1H), 3.64 (s, 3H), 3.60 - 3.51 (m, 1H), 3.06 - 2.97 (m, 1H), 2.96 - 2.87 (m, 1H), 2.86 - 2.78 (m, 1H), 2.78 - 2.68 (m, 1H), 2.28 -2.14 (m, 1H), 2.00 - 1.90 (m, 2H), 1.90 - 1.81 (m, 1H), 1.42 (s, 9H), 1.40 (s, 9H), 1.30 (s, 9H); ¹³ C NMR (126 MHz, DMSO, T= 340K) d 172.77, 172.03, 170.94, 151.03, 150.74, 138.78, 137.41, 136.51,

130.71, 130.05, 129.36, 129.18, 128.82, 128.72, 128.41, 128.17, 127.94, 127.53, 127.19, 78.58, 66.29, 66.04, 59.22, 56.19, 53.93, 52.20, 46.94, 36.90, 35.09, 30.47, 30.44, 29.97, 28.98, 28.64, 25.10. HRMS (ESI): m/z calcd for OLN _ί Oii [M+Na]+ 930.4511, found 930.4528 , . Characterization of compound 30: [a]¾ ³ = -10 (c = 0.025, MeOH); *H NMR (500 MHz, DMSO-rfc, T= 340K) d 8.70 (d, J= 9.4 Hz, 1H), 7.08 (d, J= 2.2 Hz, 1H), 7.03 (d, J= 2.2 Hz, 1H), 6.91 (d, J= 2.2 Hz, 1H), 6.74 (s, 1H), 4.71 (dd, J= 8.5, 2.6 Hz, 1H), 4.61 (s, 1H), 4.57 (t, J= 9.8 Hz, 1H), 3.80 - 3.73 (m, 2H), 3.72 (s, 3H), 3.08 - 2.98 (m, 2H), 2.93 - 2.80 (m, 2H), 2.24 - 2.14 (m, 1H), 2.10 - 1.94 (m, 2H), 1.82 (ddd, J= 11.9, 6.7, 3.3 Hz, 1H), 1.43 (s, 9H), 1.43 (s, 9H), 1.42 (s, 9H); ¹³ C NMR (126 MHz, DMSO, T= 340K) d 172.77, 172.16, 169.10, 154.38, 150.41, 138.81, 138.41, 133.39, 131.06, 130.38, 128.09, 126.95, 78.95, 59.71, 54.06, 52.64, 47.09, 37.85, 36.22, 34.99, 34.93, 30.58, 30.54, 29.36, 28.65, 24.90; HRMS (ESI): m/z calcd for C ₃₇ H _5I N ₃ 0 ₈ [M+H]+ 666.3749, found 666.3761.

Compound 32 Characterization of compound 32: [a]¾ ² = -16 (c = 0.025, MeOH); *H

NMR (500 MHz, DMSO-i ₆ ) d 8.95 (d, J= 9.5 Hz, 1H), 7.14 (d, J= 2.2 Hz, 1H), 7.00 (dd, J= 8.2, 2.3 Hz, 1H), 6.95 (dd, J= 8.2, 2.3 Hz, 1H), 6.76 (d, J= 2.3 Hz, 1H), 6.74 (d, J= 8.1 Hz, 1H), 6.72 (d, J= 8.1 Hz, 1H), 4.73 (dd, J= 8.5, 2.2 Hz, 1H), 4.55 (td, J= 9.7, 1.1 Hz, 1H), 4.16 (d, J= 3.2 Hz, 1H), 3.78 - 3.66 (m, 1H), 3.71 (s, 3H), 3.06 - 2.95 (m, 2H), 2.90 - 2.75 (m, 2H), 2.24 - 2.15 (m, 1H), 2.07 - 1.92 (m, 2H), 1.84 - 1.74 (m, 1H); ¹³ C NMR (126 MHz, DMSO) d 172.64, 172.33, 169.72, 154.78, 154.64, 134.81, 131.41, 130.80, 130.24, 129.35, 127.87, 127.04, 124.31, 116.42, 116.21, 59.44, 53.94, 52.83, 51.93, 46.85, 37.55,

36.64, 29.45, 24.85; HRMS (ESI): m/z calcd for C24H27N3O6 [M+H]+ 454.1973, found 454.1982. 7.4.3 Biaryl-bridged cyclic peptide compound 36 - Synthetic scheme (Scheme 11), compound preparation and characterization

Scheme 11

Compound S35: Thionyl chloride (6 ml_, 83 mmol, 1.8 equiv) was added dropwise to a solution of L-tyrosine (7 g, 40 mmol) in benzyl alcohol (195 ml.) at 0 °C under argon atmosphere. The reaction mixture was heated to 95 °C and stirred for 6 hours. Upon completion, the mixture was cooled to room temperature and diluted with Et ₂ 0 until white solid

Compound S35 was precipitated. The mixture was stirred for additional 16 hours at room temperature. The precipitate was filtered, washed with Et ₂ 0 and dried, affording compound S35 as a white solid (12 g, 97% yield). g, 12.5 mmol, 1 equiv) and DCC (2.7 g, 13.2 mmol, 1.05 equiv). The crude residue was purified by column chromatography affording compound 33 (EtOAc:hexane 50:50, 5.2 g, 70% yield) as a white solid.

Characterization of compound 33: [a]¾ ² = -6 (c = 0.025, MeOH); Ή NMR (400 MHz, Chloroform-c/) d 7.41 (s, 1H), 7.38 - 7.31 (m, 2H), 7.31 - 7.27 (m, 2H), 7.02 (d, J= 2.1 Hz, 1H), 6.83 - 6.72 (m, 2H), 6.69 - 6.58 (m, 3H), 6.55 (d, J= 8.1 Hz, 2H), 5.23 (d, J= 8.0 Hz, 1H), 5.19 - 5.03 (m, 2H), 4.78 (d, J= 6.5 Hz, 1H), 4.36 (d, J= 7.4 Hz, 1H), 3.06 - 2.77 (m, 4H), 1.41 (s, 9H), 1.36 (s, 9H); ¹³ C NMR (101 MHz, CDC ) d 171.72, 171.05, 155.80, 155.39, 154.18, 136.26, 134.95, 130.39, 128.68, 128.64, 128.12, 127.46, 126.94, 126.53, 116.86, 115.65, 80.76, 67.43, 55.85, 53.68, 37.82, 36.96, 34.57, 29.55, 28.30; HRMS (ESI): m/z calcd for C34H42N2O7 [M+Na]+ 613.2884, found 613.2883 , . ,

Compound 33a yield) as yellow solid.

Characterization of compound 33a: [a]¾ ² = -2 (c = 0.025, EtOH); *H NMR (500 MHz, DMSO-d6, T = 340K) d 8.99 (s, 1H), 8.17 (s, 1H), 8.03 (s, 1H), 7.55 (s, 1H), 7.37 - 7.23 (m, 10H), 7.12 (dd, J = 6.1, 2.2 Hz, 2H), 6.97 (dd, J = 9.2, 2.9 Hz, 4H), 6.65 (d, J = 8.4 Hz, 2H), 5.06 (s, 2H), 5.01 (s, 2H), 4.55 (dd, J = 7.0, 6.5 Hz, 1H), 4.36 - 4.27 (m, 1H), 4.25 (s, 1H), 3.65 (s, 3H), 3.09 - 2.82 (m, 5H), 2.68 (t, J = 12.2 Hz, 1H), 1.41 (s, 9H), 1.40 (s, 9H), 1.28 (s, 9H); ¹³ C NMR (126 MHz, DMSO, T = 340K) d 172.77, 172.24, 171.63, 156.61, 151.10, 150.68, 138.65, 137.40, 136.21, 130.77, 130.58, 130.44, 128.76, 128.72, 128.41, 128.28, 128.17, 127.98, 127.38, 127.31, 127.16, 115.66, 78.61, 66.47, 66.05, 56.21, 54.36, 52.21, 36.89, 36.79, 35.09, 30.48, 30.42, 28.59; HRMS (ESI): m/z calcd for [M+Na]+ 996.4617, found

996.4614 .

Compound 34

Characterization of compound 34: [a] , ² = +8 (c = 0.025, MeOH); *H NMR (500 MHz, DMSO- d6, T= 360K) d 8.81 (s, 1H), 8.64 (d, J = 8.9 Hz, 1H), 8.29 (d, J = 8.9 Hz, 1H), 7.04 (d, J = 8.2 Hz, 2H), 7.03 (s, 1H), 7.00 (s, 1H), 6.90 (s, 1H), 6.69 (s, 1H), 6.66 (d, J = 8.0 Hz, 2H), 5.40 (s, 1H), 4.82 (td, J = 8.9, 5.4 Hz, 1H), 4.63 (t, J = 9.5 Hz, 1H), 4.30 (t, J = 7.1 Hz, 1H), 3.69 (s, 3H), 3.05 (dd, J = 14.2, 6.6 Hz, 2H), 2.95 (t, J = 12.6 Hz, 2H), 2.87 (dd, J = 14.0, 5.4 Hz, 1H), 2.74 (dd, J = 14.0, 8.9 Hz, 1H), 1.44 (s, 9H), 1.42 (s, 9H), 1.42 (s, 9H); ¹³ C NMR (126 MHz, DMSO, T= 360K) d 172.09, 171.68, 169.78, 156.34, 154.54, 138.78, 131.62, 130.76, 130.69, 130.41, 129.40, 128.11, 127.71, 126.97, 115.51, 78.89, 54.45, 54.24, 53.41, 52.44, 38.45, 37.64, 36.40, 35.01, 34.92, 30.56, 30.53, 28.69; HRMS (ESI): m/z calcd for G _ti H^Og [M+Na]+ 754.3674, found 754.3670.

C d 36 C li tid d 34 73 1 , , , , , J= 8.5 Hz, 2H), 7.05 (dd , J= 8.2, 2.3 Hz, 1H), 7.02 (dd, J= 8.2, 2.3 Hz, 1H), 6.90 (d, J= 2.2 Hz, 1H), 6.84 (d, J= 8.2 Hz, 1H), 6.80 (d, J= 8.2 Hz, 1H), 6.70 (d, J= 8.5 Hz, 2H), 4.88 - 4.81 (m, 1H), 4.64 (dd, J = 10.3, 1.7 Hz, 1H), 3.85 (dd, = 5.7, 2.9 Hz, 1H), 3.72 (s, 3H), 3.24 (dd, = 14.4, 2.6 Hz, 1H), 3.04 - 2.80 (m, 5H); ¹³ C NMR (126 MHz, MeOD) d 172.07, 171.59, 171.21, 155.96, 153.33, 152.95, 133.25, 130.47, 130.41, 129.94, 129.24, 127.30, 126.85, 121.64, 119.11, 116.13, 116.07, 114.85, 55.07, 53.76, 51.68, 37.65, 37.45, 36.54; HRMS (ESI): m/z calcd for C28H29N3O7 [M+H]+ 520.2078, found 520.2073.

7.4.4 Biaryl-bridged cyclic core of RP 66453 (compound 39) - Synthetic scheme (Scheme 12), compound preparation and characterization

Scheme 12 p . y r Compound 37 (6.21 g, 28 mmol, 1 equiv), was reacted with A/-Boc-L-(2-t-

Bu)Tyr-OH (compound 9c) (9.5 g, 28 mmol, 1 equiv) according to general procedure A for peptide coupling, using HOBt (3.8 g, 28 mmol, 1 equiv), EDC (8 g, 42 mmol, 1.5 equiv) and Et ₃ N (12.8 mL, 92 mmol, 3.3 equiv). The crude residue was purified by column chromatography affording compound 37 (EtOAc:hexane 40:60, 11.5 g, 213 76% yield) as a white solid.

Characterization of compound 37: [a]¾ ² = -6 (c = 0.025, EtOH); Ή NMR (400 MHz, Chloroform-d) d 7.38 - 7.31 (m, 5H), 7.03 (d, J = 2.2 Hz, 1H), 6.84 (d, J = 8.0 Hz, 1H), 6.56 (dd, J = 8.0, 1.5 Hz, 1H), 6.49 (dd, J = 8.5, 2.5 Hz, 1H), 5.19 - 5.06 (m, 2H), 4.56 (dd, J = 8.4, 4.8 Hz, 1H), 4.33 (s, 1H), 3.02 - 2.90 (m, 2H), 1.90 - 1.81 (m, 1H), 1.34 - 1.23 (m, 1H), 1.13 - 0.97 (m, 1H), 0.82 (dd, J = 12.8, 7.1 Hz, 6H); ¹³ C NMR (101 MHz, CDC13) d 171.56, 171.24, 155.60, 153.78, 136.22, 135.30, 128.60, 128.45, 128.39, 127.90, 127.54, 116.72, 80.26, 67.01, 56.66, 55.88, 37.95, 37.44, 34.53, 29.54, 28.28, 24.99, 15.36, 11.54; HRMS (ESI): m/z calcd for C31H44N2O6 [M+Na]+ 563.3092, found 563.3082. (compound 9d) (11.5 g, 31 mmol, 1 equiv) according to general

Compound 38 procedure A for peptide coupling, using HOBt (4.2 g, 31 mmol, 1 equiv), Et ₃ N (14 mL, 102 mmol, 3.3 equiv) and EDC (8.8 g, 46.5 mmol, 1.5 equiv). The crude residue was purified by column chromatography affording compound 38 (EtOAc:hexane 50:50, 9.5 g, 56% yield) as a white solid.

Characterization of compound 38: 'H NMR (400 MHz, Chloroform -c/) d 7.39 - 7.22 (m, 5H), 7.17 (s, 1H), 7.00 (d, J= 2.1 Hz, 1H), 6.75 (d, 3H), 6.63 (d, J= 8.0 Hz, 2H), 6.59 - 6.50 (m, 2H), 5.56 (d, J= 8.1 Hz, 1H), 5.17 - 4.91 (m, 2H), 4.73 (dt, J= 7.7, 5.8 Hz, 1H), 4.43 (dd, J= 7.3 Hz, 1H), 3.64 (s, 3H), 3.02 - 2.77 (m, 4H), 1.33 (s, 9H); ¹³ C NMR (101 MHz, CDCb) d 171.68, 171.36, 156.32, 155.28, 154.06, 136.33, 135.88, 130.34, 128.59, 128.29, 128.06, 127.40, 126.90, 126.79, 116.84, 115.67, 67.37, 56.23, 53.67, 52.52, 37.99, 37.01, 34.52, 29.50; HRMS (ESI): m/z calcd for C31H36N2O7 [M+H]+ 549.2595, found 549.2593. _). u u w pu y u

Compound 38a chromatography, affording compound 38a

(EtOAc:hexane 60:40, 2.5 g, 67% yield) as yellow solid.

Characterization of compound 38a: [a]¾ ² = +2 (c = 0.025, EtOH); Ή NMR (500 MHz, DMSO- d ₆ ) d 9.23 (s, 1H), 8.55 (d, J= 12.2 Hz, 1H), 8.43 (s, 1H), 8.36 (d, J= 7.5 Hz, 1H), 8.11 (s, 1H), 7.50 (d, J = 20.5 Hz, 1H), 7.36 (d, J= 4.4 Hz, 5H), 7.34 - 7.24 (m, 5H), 7.20 (s, 1H), 7.16 (s, 1H), 7.07 (s, 1H), 7.00 (d, J= 8.4 Hz, 2H), 6.96 (d, J= 8.6 Hz, 1H), 6.66 (d, J= 8.4 Hz, 2H), 5.21 - 5.03 (m, 2H), 5.00 - 4.89 (m, 2H), 4.43 (dd, J= 7.3 Hz, 1H), 4.38 - 4.30 (m, 1H), 4.31 - 4.12 (m, 2H), 3.55 (s, 3H), 2.98 - 2.79 (m, 4H), 2.70 (dd, J = 14.1, 10.7 Hz, 2H), 1.91 - 1.74 (m, 1H), 1.39 (s, 9H), 1.38 (s, 9H), 1.29 (s, 9H), 1.24 - 1.12 (m, 2H), 0.90 - 0.75 (m, 6H); ¹³ C NMR (126 MHz, DMSO) d 172.42, 171.76, 156.51, 156.32, 155.74, 150.49, 138.70, 137.39, 136.28, 130.99, 130.50, 128.87, 128.76, 128.68, 128.60, 128.54, 128.20, 128.10, 127.35, 115.53, 78.46, 66.40, 65.82, 56.77, 54.47, 52.20, 37.03, 36.52, 35.15, 30.42, 28.60, 25.11, 15.82,

11.57; HRMS (ESI): m/z calcd for C62H78N4O13 [M+Na]+ 1109.5458, found 1109.5455. 2 steps) as a white solid.

Characterization of compound 40: [a]¾ ² = -6 (c = 0.025, EtOH); *H NMR (500 MHz, DMSO-ί/b, T = 360K) d 8.89 (s, 1H), 8.49 (s, 1H), 8.42 (d, J= 7.1 Hz, 1H), 7.98 (s, 1H), 7.83 (d, J= 7.0 Hz, 1H), 7.02 (s, 1H), 7.00 (d, J= 8.4 Hz, 2H), 6.97 (s, 1H), 6.95 (s, 1H), 6.68 (d, J= 8.6 Hz, 2H), 6.67 (s, 1H), 4.59 (t, J = 9.9 Hz, 1H), 4.55 - 4.48 (m, 1H), 4.49 - 4.40 (m, 1H), 4.40 - 4.33 (m, 1H), 3.62 (s, 3H), 3.22 - 3.07 (m, 1H), 3.00 - 2.70 (m, 5H), 1.75 - 1.60 (m, 1H), 1.45 (s, 9H), 1.43 (s, 9H), 1.42 (s, 9H), 1.35 - 1.25 (m, 1H),

I.20 - 0.98 (m, 1H), 0.98 - 0.48 (m, 6H); ¹³ C NMR (126 MHz, DMSO, T = 360K) d 172.05, 171.93, 171.67, 171.40, 156.66, 154.71, 138.97, 138.85, 131.31, 130.74, 130.53, 130.35, 129.12, 127.77, 127.38, 127.26, 115.69, 78.90, 57.22, 54.19, 52.09, 37.96, 36.76, 34.99, 34.94, 30.55, 28.69, 28.64, 25.05, 15.66,

II.03; HRMS (ESI): m/z calcd for C ₄₇ H ₆₄ N ₄ O ₁₀ [M+Na]+ 867.4515, found 867.4509.

Compound 39 (MeOH:DCM 10:90, 49 mg, 90% yield) as an off-white solid.

Characterization of compound 39: [a] ¾ ³ = -8 (c = 0.025, MeOH); *H NMR (500 MHz, DMSO-rfc) d 8.69 (d, J= 8.9 Hz, 1H), 8.43 (d, J= 9.3 Hz, 1H), 8.20 (d, J= 7.5 Hz, 1H), 6.99 (d, J= 8.3 Hz, 2H), 6.97 (s, 1H), 6.93 (d, J = 6.2 Hz, 1H), 6.92 (d, J= 6.8 Hz, 1H), 6.70 (d, J= 8.5 Hz, 3H), 6.66 (d, J= 8.1 Hz, 2H), 4.60 (t, J= 10.2 Hz, 1H), 4.46 - 4.35 (m, 2H), 3.81 (t, J= 4.9 Hz, 1H), 3.59 (s, 3H), 2.96 - 2.70 (m, 6H), 1.68 - 1.55 (m, 1H), 1.54 - 1.43 (m, 1H), 1.12 - 0.95 (m, 1H), 0.80 (t, J= 7.4 Hz, 3H), 0.78 (d, J = 6.7 Hz, 3H); ¹³ C NMR (126 MHz, DMSO) d 172.35, 171.98, 171.26, 171.02, 156.58, 155.47, 155.03, 132.33, 130.46, 130.10, 129.72, 129.42, 129.06, 127.93, 127.67, 127.24, 125.86, 122.42, 119.86, 116.77, 116.66, 115.52, 63.50, 56.79, 54.38, 54.29, 53.53, 52.27, 38.26, 37.89, 36.44, 36.36, 25.02, 15.61, 11.18; HRMS (ESI): m/z calcd for C ₃₄ H ₄₀ N ₄ O ₈ [M+H]+ 633.2919, found 633.2905

7.5 Synthesis of biaryl-bridged cyclic peptides according to Approach B.

7.5.1 Arylomycin cyclic core compound 16 - Synthetic scheme (Scheme 13), compound preparation and characterization

Scheme 13

Compound 13 reduced pressure, affording compound 13a (2.6 g, 94% yield) as a white solid. 1.5 equiv). The residue was purified by column chromatography, affording compound 17 (EtOAc:hexane 50:50, 2.3 g, 50% yield) as a white solid. Characterization of compound 17: [a]¾ ³ = +18 (c = 0.025, MeOH); *H NMR (500 MHz, DMSO-rfc, T= 340K) d 9.18 (s, 1H), 8.93 (s, 1H), 7.98 (d, J= 7.3 Hz, 1H), 7.81 (d, J= 7.3 Hz, 1H), 7.03 (s, 1H), 6.96 (s, 1H), 6.91 (d, J= 8.4 Hz, 1H), 6.82 (d, J= 8.0 Hz, 1H), 6.75 (d, 1H), 6.69 (d, 1H), 5.62 (s, 1H), 4.42 (t, J = 7.1 Hz, 2H), 3.57 (s, 3H), 2.96 - 2.80 (m, 2H), 2.57 (s, 3H), 1.42 (s, 9H), 1.34 (s, 9H), 1.33 (s, 9H), 1.22 (d, 3H); ¹³ C NMR (126 MHz, DMSO, G= 340K) d 172.55, 172.26, 170.09, 155.89, 155.82, 155.00, 135.85, 135.63, 127.64, 127.55, 127.47, 127.04, 126.45, 116.68, 116.53, 79.49, 62.43, 54.51, 52.00, 48.56, 48.51, 37.08, 34.67, 34.61, 31.76, 29.94, 29.83, 28.61, 28.55, 18.69; HRMS (ESI): m/z calcd for C ₃₅ H _5I N ₃ 0 ₈ [M+Na]+ 664.3598, found 664.3597. compound 15 (44.3 mg, 69% yield) as a yellow solid.

Compound 15

Characterization of compound 15: [a]¾ ⁴ = +26 (c = 0.025, MeOH); *H NMR (500 MHz, DMSO-d6, T = 360K) d 9.08 (s, 1H), 8.78 (d, J = 5.7 Hz, 1H), 8.17 (d, J = 8.9 Hz, 1H), 7.11 (s, 1H), 7.08 (s, 1H), 6.84 (s, 1H), 6.82 (s, 1H), 5.91 (s, 1H), 4.87 - 4.69 (m, 2H), 3.71 (s, 3H), 3.26 (dd, J = 16.9, 2.6 Hz, 1H), 3.07 (dd, J = 16.8, 11.6 Hz, 1H), 2.59 (s, 3H), 1.46 (s, 9H), 1.44 (s, 9H), 1.43 (s, 9H), 1.23 (d, J = 6.7 Hz, 3H); ¹³ C NMR (126 MHz, DMSO, T = 360K) d 172.66, 172.33, 170.72, 151.29, 150.24, 140.20, 140.08, 132.45, 130.70, 129.96, 129.47, 126.75, 126.42, 79.46, 62.13, 52.50, 51.59, 48.08, 35.16, 35.10, 33.99, 32.16, 30.59, 30.48, 28.68, 19.29; HRMS (ESI): m/z calcd for C ₃₅ H ₄₉ N ₃ O ₈ [M+Na]+ 662.3412, found 662.3408

Compound 16: Was prepared from compound 15 as described hereinbefore. 7.5.2 Biaryl-bridged cyclic peptide compound 27 - Synthetic scheme (Scheme 14), compound preparation and characterization

Scheme 14 1.5 equiv). The residue was purified by column chromatography, affording compound 21 (EtOAc:hexane 40:60, 2.1 g, 50% yield) as a white solid. Characterization of compound 21: [a]¾ ⁴ = +20 (c = 0.025, MeOH); Ή NMR (500 MHz, DMSO-rfc) d 9.31 (s, 1H), 9.17 (s, 1H), 8.24 (d, J= 7.3 Hz, 1H), 8.08 (d, J= 7.6 Hz, 1H), 7.14 (d, J= 2.3 Hz, 1H), 6.97 (dd, J= 8.3, 2.2 Hz, 1H), 6.89 (d, J= 2.2 Hz, 1H), 6.79 (dd, J= 8.1, 2.2 Hz, 1H), 6.67 (dd, J= 8.5 Hz, 2H), 5.03 (d, J= 8.7 Hz, 1H), 4.38 (p, J= 7.2 Hz, 1H), 4.31 (q, J= 7.3 Hz, 1H), 3.54 (s, 3H), 2.87 - 2.70 (m, 2H), 1.38 (s, 9H), 1.31 (s, 9H), 1.30 (s, 9H), 1.18 (d, J = 7.2 Hz, 3H). ¹³ C NMR (126 MHz, DMSO) d 172.44, 172.34, 170.42, 155.72, 155.30, 154.98, 135.29, 129.01, 127.57, 127.47, 126.84, 126.20, 116.49, 116.19, 78.76, 58.16, 54.56, 52.14, 48.08, 36.76, 34.79, 34.61, 29.79, 29.75, 28.64, 19.18. HRMS (ESI): m/z calcd for C ₃₄ H ₄₉ N ₃ 0 ₈ [M+H]+ 628.3592, found 628.3604.

Characterization of compound 24: [a]¾ ² = +4 (c = 0.025, MeOH);

*H NMR (500 MHz, DMSO-i ₆ , T= 350K) d 8.86 (d , J= 8.4 Hz, 1H), 8.47 (d, J= 8.9 Hz, 1H), 7.31 (d, J = 2.4 Hz, 1H), 7.11 (d, J= 2.3 Hz, 1H), 6.90 (d, J= 9.9 Hz, 2H), 6.24 (s, 1H), 5.47 (d, J= 8.7 Hz, 1H), 4.79 (dq, J= 8.8, 6.7 Hz, 1H), 4.69 (t, J= 10.1 Hz, 1H), 3.72 (s, 3H), 3.14 (d, J= 15.8 Hz, 1H), 2.98 (dd, J = 15.8, 11.8 Hz, 1H), 1.45 (s, 9H), 1.43 (s, 9H), 1.43 (s, 9H), 1.25 (d, = 6.7 Hz, 3H). ¹³ C NMR (126 MHz, DMSO, T = 35 OK) d 172.46, 172.33, 170.28, 155.42, 150.78, 150.50, 139.64, 139.53, 132.06, 130.69, 130.68, 130.55, 130.43, 130.28, 126.82, 78.93, 56.52, 52.58, 48.65, 35.24, 35.09, 34.80, 30.53, 30.49,

28.70, 19.45. HRMS (ESI): m/z calcd for C3 ₄ H ₄₇ N3O8 [M+Na]+ 648.3255, found 648.3270.

Com ound 27: C clic e tide (com ound 24) (51 5 0 082 mg, y e ) as an o -w e so .

Characterization of compound 27: [a]¾ ³ = +6 (c = 0.025, MeOH); Ή NMR (500 MHz, D SO-c/,) d 9.22 (d, J= 8.3 Hz, 1H), 8.75 (d, J= 9.1 Hz, 1H), 7.22 (dd, J= 8.3, 2.5 Hz, 1H), 6.96 (d, J= 2.2 Hz, 1H), 6.94 (dd, J= 8.1, 2.2 Hz, 1H), 6.91 (d, J= 2.5 Hz, 1H), 6.69 (d, J= 8.4 Hz, 1H), 6.64 (d, J= 8.0 Hz, 1H), 4.83 (dq, J= 8.9, 6.8 Hz, 1H), 4.79 (s, 1H), 4.60 (ddd, J= 11.1, 8.2, 2.1 Hz, 1H), 3.69 (s, 3H), 3.04 (dd, J = 16.0, 2.2 Hz, 1H), 2.94 (dd, J = 16.1, 11.6 Hz, 1H), 1.22 (d, J = 6.7 Hz, 3H). ¹³ C NMR (126 MHz, DMSO) d 172.53, 172.29, 170.73, 158.38, 156.29, 131.39, 130.41, 128.90, 127.95, 127.82, 127.43, 127.29, 117.42, 117.36, 55.63, 52.78, 52.73, 48.30, 34.08, 19.50. HRMS (ESI): m/z calcd for C ₂₁ H ₂₃ N ₃ O ₆ [M+H]+ 414.1660, found 414.1667. 7.5.3 Biaryl-bridged cyclic peptide compound 28 - Synthetic scheme (Scheme 15), compound preparation and characterization

Scheme 15 Compound 22 mg, 2.8 mmol, 1 equiv), Et ₃ N (1.2 ml_, 9.2 mmol, 3.3 equiv) and EDC (0.8 g, 4.4 mmol, 1.5 equiv). The residue was purified by column chromatography affording compound 22 (EtOAc:hexane 60:40, 1.2 g, 67% yield) as a white solid.

Characterization of compound 22: [a]¾ ² = +2 (c = 0.025, MeOH); Ή NMR (500 MHz, DMSO-tfc) d 9.17 (s, 1H), 9.07 (s, 1H), 8.32 (d, J= 7.3 Hz, 1H), 7.88 (d, J= 7.7 Hz, 1H), 7.02 (d, J= 2.2 Hz, 1H), 6.93 (d, J= 2.2 Hz, 1H), 6.88 - 6.82 (m, 2H), 6.68 (d, J= 8.0 Hz, 1H), 6.65 (d, J= 8.1 Hz, 1H), 4.45 - 4.31 (m, 2H), 4.11 (td, J= 9.6, 3.8 Hz, 1H), 3.57 (s, 3H), 2.91 - 2.81 (m, 3H), 2.60 (dd, J= 14.1, 10.5 Hz, 1H), 1.33 (s, 9H), 1.32 (s, 9H), 1.31 (s, 9H), 1.21 (d, J= 6.7 Hz, 3H); ¹³ C NMR (126 MHz, DMSO) d 172.70, 172.43, 171.88, 155.63, 155.00, 154.61, 135.29, 134.98, 128.15, 127.71, 127.63, 127.53, 126.92, 116.50, 116.14, 78.40, 56.10, 54.52, 52.17, 48.19, 37.32, 36.77, 34.66, 34.63, 29.87, 29.81, 28.62, 19.15. HRMS (ESI): m/z calcd for C ₃₅ H _5I N ₃ 0 ₈ [M+H]+ 642.3749, found 642.3760. compound 25 (42.5 mg, 33% yield) as a yellow solid. Compound 25 Characterization of compound 25: [a]¾ ⁴ = -8 (c = 0.025, MeOH); 'H NMR (500 MHz, DMSOA, T= 350K) d 8.65 (d, J= 9.0 Hz, 1H), 8.35 (d, J= 8.6 Hz, 1H), 7.06 (d, J = 2.3 Hz, 1H), 7.00 (s, 1H), 6.94 (d, J= 2.2 Hz, 1H), 6.69 (d, J= 2.2 Hz, 1H), 4.71 (dq, J= 8.7, 7.0 Hz, 1H),

4.63 (t, J= 9.9 Hz, 1H), 4.36 (t, 1H), 3.72 (s, 3H), 3.06 - 3.01 (m, 2H), 2.97 - 2.89 (m, 2H), 1.45 (s, 9H), 1.42 (s, 18H), 1.26 (d, J= 7.0 Hz, 3H); ¹³ C NMR (126 MHz, DMSO, T= 350K) d 172.70, 172.22, 169.69, 154.64, 150.68, 150.25, 138.93, 131.84, 130.69, 130.63, 129.65, 129.10, 127.85, 127.81, 127.18, 78.90, 52.55, 52.53, 48.25, 48.20, 37.73, 36.43, 35.02, 34.95, 30.56, 30.53, 28.69, 19.12. HRMS (ESI): m/z calcd for C35H49N3O8 [M+Na]+ 662.3412, found 662.3422. , .

Characterization of compound 28: [a]¾ ³ = -2 (c = 0.025, MeOH); Ή NMR (500 MHz, DMSO-ί/b) d

8.93 (d, J= 9.0 Hz, 1H), 8.62 (d, J= 8.8 Hz, 1H), 6.98 (d, J= 2.3 Hz, 1H), 6.94 (dd, J= 8.3, 2.2 Hz, 2H), 6.70 (s, 1H), 6.68 (d, = 3.4 Hz, 2H), 4.71 (p, = 7.2 Hz, 1H), 4.60 (ddd, J= 11.0, 8.9, 1.9 Hz, 1H), 3.75 (s, 1H), 3.70 (s, 3H), 3.02 (dd, J= 15.2, 2.0 Hz, 1H), 2.95 - 2.83 (m, 3H), 1.22 (d, J= 7.1 Hz, 3H); ¹³ C NMR (126 MHz, DMSO) d 172.61, 172.44, 170.94, 155.22, 132.74, 130.26, 130.09, 129.28, 128.63, 127.79, 127.58, 125.84, 122.41, 119.85, 116.62, 116.52, 54.14, 52.94, 52.78, 47.88, 38.54, 35.71, 19.36;

HRMS (ESI): m/z calcd for C22H25N3O6 [M+H]+ 428.1816, found 428.1824. 7.5.4 Biaryl-bridged cyclic peptide compound 32 - Synthetic scheme (Scheme 16), compound preparation and characterization

Scheme 16

Compound 31b: A/-Boc-L-(2-f-Bu)Tyr-L-Pro-OBn (compound 31) (2.4 g, 4.6 mmol, 1 equiv) and Pd/C (10 mol%) were dissolved in MeOH (50 ml.) and stirred under H ₂ atmosphere (1 atm) for 6 hours at room temperature. Upon completion, the mixture was filtered through celite bed and the filtrate was evaporated under reduced pressure, affording

Compound 31b compound 31b (1.9 g, 95% yield) as a white solid. . , .

Characterization of compound 29 (mixture of atropoisomers): 'H NMR (500 MHz, DMSO-rfc) d 9.22 (s), 9.14 (s), 9.10 (s), 9.07 (s), 8.39 (d, J= 8.2 Hz), 8.07 (d, J= 7.3 Hz), 7.19 (d, J= 5.0 Hz), 7.05 (d, J = 1.9 Hz), 6.97 - 6.83 (m), 6.79 (dd, J= 8.1, 2.1 Hz), 6.68 (dd, J= 8.1, 1.5 Hz), 6.65 (dd, J= 8.1, 1.3 Hz), 4.43 - 4.33 (m), 4.18 - 4.10 (m), 3.62 - 3.57 (m), 3.55 (s), 3.53 (s), 3.51 - 3.46 (m), 3.18 - 3.09 (m), 3.09 - 2.99 (m), 2.89 - 2.82 (m), 2.81 - 2.73 (m), 2.70 - 2.59 (m), 2.07 - 1.93 (m), 1.89 - 1.79 (m), 1.79 - 1.68 (m), 1.39 (s), 1.32 (s), 1.31 (s), 1.29 (s); ¹³ C NMR (126 MHz, DMSO) d 172.54, 172.10, 172.01, 171.14, 170.99, 156.10, 155.69, 155.18, 154.98, 154.81, 154.68, 135.49, 135.25, 135.10, 128.20, 128.04, 127.84, 127.75, 127.70, 127.61, 127.58, 127.46, 127.21, 126.91, 126.47, 116.47, 116.23, 78.98, 78.30, 60.02, 59.55, 54.90, 54.51, 54.36, 54.28, 52.20, 52.11, 47.06, 46.47, 37.35, 36.97, 36.35, 35.93, 34.64, 34.58, 30.73, 29.85, 29.82, 29.71, 29.68, 29.34, 28.68, 28.64, 28.32, 24.87, 21.54. HRMS (ESI): m/z calcd for C ₃₇ H ₅₃ N ₃ 0 ₈ [M+Na]+ 668.3905, found 668.3916. .

Compound 32: Was prepared from compound 30 as described hereinbefore.