METHODS OF USE THEREOF

Cross-Reference to Related Applications

This application claims the benefit of, and priority to, U.S. Provisional Patent Application No. 62/831,046, filed April 8, 2019, and U.S. Provisional Patent Application No. 62/835,871, filed April 18, 2019, the contents of each of which are incorporated by reference.

Field of the Invention

The invention generally relates to compositions containing steroids with altered pharmacokinetic properties and methods of using the same.

Background

Brain excitability, defined as the level of arousal of an animal, is regulated by various neurotransmitters that bind to neuronal receptors that control the flow of ions across neuronal membranes. For example, activity of the neurotransmitter gamma-aminobutyric acid (GABA), which activates ionotropic GABA _A receptors, is critical for brain function. Interactions between GABA and GABA _A receptors are altered a variety of disorders of the central nervous system (CNS), such as convulsive disorders, substance abuse, sleep disorders, schizophrenia spectrum disorders, and panic and anxiety disorders.

Several neurosteroids have been identified as either positive or negative modulators of GABA _A receptors. Accordingly, neurosteroids have been used to treat CNS disorders associated with altered GABA levels. Such neurosteroids include compounds such as those disclosed in U.S. Patent Nos. 9,365,611; 9,512,165; and 9,725,481. However, the number of possible steroid variants is vast, so it is unknown whether compounds currently being investigated have optimal pharmacological properties, such as bioavailability, stability, and activity.

Summary

The invention provides neurosteroids having altered, e.g., improved, potency, bioavailability, and pharmacokinetic properties and methods of using such neurosteroids for the treatment of CNS disorders. The invention is based on the finding that compounds having a steroid structural core are effective GABA _A receptor modulators. The compounds also contain substituents at other positions on the steroid core, which stabilize the molecules and allow for attachment of moieties that alter or improve solubility and bioavailability.

In an aspect, the invention provides compounds of formula (I):

wherein:

A is an optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₀ , -SR ₃₁ , or -N(R ₃₁ ) ₂ ;

R _1A and R _1B are according to (i) or (ii) as follows:

(i) each of R _1A and R _1B is independently hydrogen, cyano, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted alkoxy, optionally substituted alkoxide, cyano-substituted alkyl, -SR ₃₁ , -OR ₃₁ , -SSR ₃₁ , -N(R ₃₁ ) ₂ , - NR ₃₁ N(R ₃₁ ) ₂ , -NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , -S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ , with the proviso that R _1A and R _1B are not both hydrogen, or

(ii) R _1A and R _1B together are =O, =NR ₃₁ , or =S,

each of R ₂ and R ₃ is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ , or R ₂ and R ₃ together are =NR ₃₁ or =S;

R ₄ and R ₅ are according to (iii), (iv), or (v) as follows:

(iii) if R ₄ is hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -NHC(=O)R ₃₁ , - NHC(=O)OR ₃₁ , -S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ , then R ₅ is -OR ₃₁ , -SR ₃₁ , or -N(R ₃₁ ) ₂ ,

(iv) if R ₄ is hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ , -NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , -S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ , then R ₅ is halogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ , or

(v) R ₄ and R ₅ together form an optionally substituted ringed structure comprising

3-6 atoms;

each of R ₆ , R ₇ , R ₈ , and R ₉ , is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ ;

each of R ₁₀ and R ₁₁ is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ , or R ₁₀ and R ₁₁ together are =NR ₃₁ or =S;

each of R ₁₂ and R ₁₃ is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ , or R ₁₂ and R ₁₃ together are =NR ₃₁ or =S;

each of R ₁₄ and R ₁₅ is independently absent, hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ , or R ₁₄ and R ₁₅ together are =NR ₃₁ or =S;

each of R ₁₆ and R ₁₇ is independently absent, hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ , or R ₁₆ and R ₁₇ together are =NR ₃₁ or =S;

each of R ₁₈ and R ₁₉ is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ , or R ₁₈ and R ₁₉ together are =NR ₃₁ or =S;

R ₂₀ and R ₂₁ are according to (vi) or (vii) as follows:

(vi) if C ₁ and C ₂ form a single bond, then either:

(a) each of R ₂₀ and R ₂₁ is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ , or

(b) R ₂₀ and R ₂₁ together are =NR ₃₁ or =S; or

(vii) if C ₁ and C ₂ form a double bond, then R ₂₀ is absent and R ₂₁ is hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,- NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , -S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ , R ₂₂ is absent, hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , - SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , -S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ ;

R ₂₃ is halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , - N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , -S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ ;

each of R ₂₄ and R ₂₅ is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ , or R ₂₄ and R ₂₅ together are =O;

each of R ₂₆ and R ₂₇ is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ , or R ₂₀ and R ₂₁ together are =NR ₃₁ or =S;

R ₂₈ and R ₂₉ are according to (viii), (ix), or (x) as follows:

(viii) each of R ₂₈ and R ₂₉ is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ ,

(ix) R ₂₈ 8nd R ₂₉ together are =O, or

(x) R ₂₈ and R ₂₉ together with the carbon atom to which they are attached form a ring;

each instance of R ₃₀ is independently hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, carbocyclyl, heterocyclyl, aryl, or heteroaryl; each instance of R ₃₁ is independently hydrogen, hydroxy, alkyl, alkenyl, alkynyl, alkoxy, carbocyclyl, heterocyclyl, aryl, heteroaryl, amine, nitrate, nitrite, thiol, thioether, thioester, sulfate, sulfite, disulfide, sulfoxide, phosphate, phosphate ester, thiophosphate, thiophosphate ester, phosphonate, phosphonate ester, thiophosphonate, thiophosphonate ester, an oxygen protecting group when attached to an oxygen atom, a sulfur protecting group when attached to a sulfur atom, a nitrogen protecting group when attached to a nitrogen atom, or two R ₃₁ groups are joined to form an heterocyclic or heteroaryl ring;

each instance of R ₃₂ is independently hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, or optionally substituted heteroaryl; and each instance of R ₃₃ is independently hydrogen, an optionally substituted C _1-6 alkyl, optionally substituted C _2-6 alkenyl, optionally substituted C _2-6 alkynyl, or optionally substituted C _3-6 carbocyclyl;

wherein:

(xi) if C ₁ and C ₂ form a single bond, R _1A and R _1B together are =O, and R ₄ and R ₅ do not form a ringed structure, then at least one of the following conditions is satisfied:

(a) at least one of R ₂ , R ₃ , R ₆ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , or R ₂₂ is not H;

(b) neither of R ₁₂ and R ₁₃ is H;

(c) neither of R ₁₄ and R ₁₅ is H;

(d) neither of R ₁₆ and R ₁₇ is H;

(e) neither of R ₁₈ and R ₁₉ is H;

(f) neither of R ₂₀ and R ₂₁ is H; and

(g) neither of R ₂₆ and R ₂₇ is H;

(xii) if C ₁ and C ₂ form a single bond and either of R _1A and R _1B is optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkoxy, or hydroxyl, and R ₄ and R ₅ do not form a ringed structure, then at least one of the following conditions is satisfied:

(a) at least one of R ₂ , R ₃ , R ₆ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , R ₂₀ , R ₂₁ , or R ₂₂ is not H;

(b) neither of R ₁₂ and R ₁₃ is H;

(c) neither of R ₁₆ and R ₁₇ is H;

(d) neither of R ₁₈ and R ₁₉ is H; and

(e) neither of R ₂₆ and R ₂₇ is H;

(xiii) if C ₁ and C ₂ form a single bond, R _1A and R _1B together are =O, both R ₁₆ and R ₁₇ are present, and neither of R ₁₆ and R ₁₇ is H, then R ₂₃ is alkyl; and (xiv) if C ₁ and C ₂ form a single bond and either of R _1A and R _1B is alkyl, then:

(a) R ₂₈ , and R ₂₉ , are not -OH; and

(b) A is not substituted with -OH; and

(xv) if C ₁ and C ₂ form a single bond, R _1A and R _1B together are =S or =NR ₃₁ , and

R ₄ and R ₅ do not form a ringed structure, then at least one of the following conditions is satisfied:

(a) at least one of R ₂ , R ₃ , R ₁₀ , R ₁₁ , R ₁₄ , R ₁₅ , R ₁₈ , R ₁₉ , R ₂₀ , R ₂₁ , R ₂₆ and R ₂₇ is not H;

(b) neither of R ₁₂ and R ₁₃ is H; and

(c) neither of R ₂₄ and R ₂₅ is H.

In certain embodiments, R _1A and R _1B together are =NH or =S. In certain embodiments,

R _1A and R _1B together are =CH ₂ .

In certain embodiments and at least one of R ₂₀ and R ₂₁ is not H.

In certain embodiments, R ₂₃ is an optionally substituted alkyl. In certain embodiments, R ₂₃ is a C ₁ -C ₆ alkyl. In certain embodiments, R ₂₃ is methyl.

In certain embodiments, R ₇ is an optionally substituted alkyl. In certain embodiments, R ₇ is a C ₁ -C ₆ alkyl. In certain embodiments, R ₇ is methyl.

In certain embodiments, A is an optionally substituted heteroaryl. In certain

embodiments, A is an optionally substituted pyrazole. In certain embodiments, A is represented by the following structure:

In certain embodiments, at least one of R ₂₀ and R ₂₁ is not hydrogen.

In certain embodiments, the compound of formula (I) has a structure represented by one of formulas (la), (lb), (Ic), (Id), (Ie), (If), (Ig), (Ih), and (Ii):

In certain embodiments, the compound of formula (I) has a structure represented by one of formulas (la-1), (Ib-1), (Ic-1), (Id-1), (Ie-1), (If-1), (Ig-1), (Ih-1), and (Ii-1):

Detailed Description

The invention provides neurosteroids that are effective GABAA receptor modulators and have different pharmacokinetic properties from previously described neurosteroids. The neurosteroids of the invention are therefore useful for treating CNS disorders.

Definitions

Definitions of specific functional groups and chemical terms are described in more detail below. The chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75th Ed., inside cover, and specific functional groups are generally defined as described therein. Additionally, general principles of organic chemistry, as well as specific functional moieties and reactivity, are described in Thomas Sorrell, Organic Chemistry, University Science Books, Sausalito, 1999; Smith and March, March' s Advanced Organic Chemistry, 5th Edition, John Wiley & Sons, Inc., New York, 2001; Larock, Comprehensive Organic Transformations, VCH Publishers, Inc., New York, 1989; and Carruthers, Some Modern Methods of Organic Synthesis, 3rd Edition,

Cambridge University Press, Cambridge, 1987.

Compounds described herein can comprise one or more asymmetric centers, and thus can exist in various isomeric forms, e.g., enantiomers and/or diastereomers. For example, the compounds described herein can be in the form of an individual enantiomer, diastereomer or geometric isomer, or can be in the form of a mixture of stereoisomers, including racemic mixtures and mixtures enriched in one or more stereoisomer. Isomers can be isolated from mixtures by methods known to those skilled in the art, including chiral high pressure liquid chromatography (HPLC), supercritical fluid chromatography (SFC), and the formation and crystallization of chiral salts; or preferred isomers can be prepared by asymmetric syntheses. See, for example, Jacques et al., Enantiomers, Racemates and Resolutions (Wiley Interscience, New York, 1981); Wilen et al., Tetrahedron 33:2725 (1977); Eliel, Stereochemistry of Carbon

Compounds (McGraw-Hill, NY, 1962); and Wilen, Tables of Resolving Agents and Optical Resolutions p. 268 (E.L. Eliel, Ed., Univ. of Notre Dame Press, Notre Dame, IN 1972). The invention additionally encompasses compounds described herein as individual isomers substantially free of other isomers, and alternatively, as mixtures of various isomers.

As used herein a pure enantiomeric compound is substantially free from other

enantiomers or stereoisomers of the compound (i.e., in enantiomeric excess). In other words, an "S" form of the compound is substantially free from the "R" form of the compound and is, thus, in enantiomeric excess of the "R" form. The term "enantiomerically pure" or "pure enantiomer" denotes that the compound comprises more than 75% by weight, more than 80% by weight, more than 85% by weight, more than 90% by weight, more than 91% by weight, more than 92% by weight, more than 93% by weight, more than 94% by weight, more than 95% by weight, more than 96% by weight, more than 97% by weight, more than 98% by weight, more than 98.5% by weight, more than 99% by weight, more than 99.2% by weight, more than 99.5% by weight, more than 99.6% by weight, more than 99.7% by weight, more than 99.8% by weight or more than 99.9% by weight, of the enantiomer. In certain embodiments, the weights are based upon total weight of all enantiomers or stereoisomers of the compound.

In the compositions provided herein, an enantiomerically pure compound can be present with other active or inactive ingredients. For example, a pharmaceutical composition comprising enantiomerically pure R-compound can comprise, for example, about 90% excipient and about 10% enantiomerically pure R-compound. In certain embodiments, the enantiomerically pure R- compound in such compositions can, for example, comprise, at least about 95% by weight R- compound and at most about 5% by weight S-compound, by total weight of the compound. For example, a pharmaceutical composition comprising enantiomerically pure S-compound can comprise, for example, about 90% excipient and about 10% enantiomeric ally pure S-compound. In certain embodiments, the enantiomerically pure S compound in such compositions can, for example, comprise, at least about 95% by weight S compound and at most about 5% by weight R-compound, by total weight of the compound. In certain embodiments, the active ingredient can be formulated with little or no excipient or carrier.

Compounds described herein may also comprise one or more isotopic substitutions. For example, H may be in any isotopic form, including ¹ H, ² H (D or deuterium), and (T or tritium); C may be in any isotopic form, including ¹² C, ¹³ C, and ¹⁴ C; N may be any isotopic form, including ¹⁴ N and ¹⁵ N; O may be in any isotopic form, including ¹⁶ O and ¹⁸ O; and the like.

The articles "a" and "an" may be used herein to refer to one or to more than one (i.e. at least one) of the grammatical objects of the article. By way of example "an analogue" means one analogue or more than one analogue.

When a range of values is listed, it is intended to encompass each value and sub-range within the range. For example " C _1-6 alkyl" is intended to encompass, C ₁ , C ₂ , C ₃ , C ₄ , C ₅ , C ₆ , C _1-6 , C _1-5 , C _1-4 , C _1-3 , C _1-2 , C _2-6 , C _2-5 , C _2-4 , C _2-3 , C _3-6 , C _3-5 , C _3-4 , C _4-6 , C _4-5 , and C _5-6 alkyl.

The following terms are intended to have the meanings presented therewith below and are useful in understanding the description and intended scope of the present invention.

"Alkyl" refers to a radical of a straight-chain or branched saturated hydrocarbon group having from 1 to 20 carbon atoms (" C _1-20 alkyl"). In some embodiments, an alkyl group has 1 to 12 carbon atoms (" C _{1- 12} alkyl"). In some embodiments, an alkyl group has 1 to 8 carbon atoms ("C _{1- 8} alkyl"). In some embodiments, an alkyl group has 1 to 6 carbon atoms ("C _1-6 alkyl", also referred to herein as "lower alkyl"). In some embodiments, an alkyl group has 1 to 5 carbon atoms ("C _1-5 alkyl"). In some embodiments, an alkyl group has 1 to 4 carbon atoms (" C _1-4 alkyl"). In some embodiments, an alkyl group has 1 to 3 carbon atoms ("C _1-3 alkyl"). In some embodiments, an alkyl group has 1 to 2 carbon atoms ("C _1-2 alkyl"). In some embodiments, an alkyl group has 1 carbon atom (" C ₁ alkyl"). In some embodiments, an alkyl group has 2 to 6 carbon atoms ("C _2-6 alkyl"). Examples of C _1-6 alkyl groups include methyl (C ₁ ), ethyl (C ₂ ), n- propyl (C ₃ ), isopropyl (C ₃ ), n-butyl (C ₄ ), tert-butyl (C ₄ ), sec -butyl (C ₄ ), isobutyl (C ₄ ), n-pentyl (C ₅ ), 3-pentanyl (C ₅ ), amyl (C ₅ ), neopentyl (C ₅ ), 3-methyl-2-butanyl (C ₅ ), tertiary amyl (C ₅ ), and n-hexyl (C ₆ ). Additional examples of alkyl groups include n-heptyl (C ₇ ), n-octyl (C ₈ ) and the like. Unless otherwise specified, each instance of an alkyl group is independently optionally substituted, i.e., unsubstituted (an "unsubstituted alkyl") or substituted (a "substituted alkyl") with one or more substituents; e.g., for instance from 1 to 5 substituents, 1 to 3 substituents, or 1 substituent. In certain embodiments, the alkyl group is unsubstituted C _1-10 alkyl (e.g., -CH ₃ ). In certain embodiments, the alkyl group is substituted C _1-10 alkyl. Common alkyl abbreviations include Me (-CH ₃ ), Et (-CH ₂ CH ₃ ), iPr (-CH(CH ₃ ) ₂ ), nPr (- CH ₂ CH ₂ CH ₃ ), n-Bu (- CH ₂ CH ₂ CH ₂ CH ₃ ), or i-Bu (-CH ₂ CH(CH ₃ ) ₂ ).

Alkenyl" refers to a radical of a straight-chain or branched hydrocarbon group having from 2 to 20 carbon atoms, one or more carbon-carbon double bonds, and no triple bonds ("C _2-20 alkenyl"). In some embodiments, an alkenyl group has 2 to 10 carbon atoms ("C _2-10 alkenyl"). In some embodiments, an alkenyl group has 2 to 8 carbon atoms ("C _2-8 alkenyl"). In some embodiments, an alkenyl group has 2 to 6 carbon atoms ("C _2-6 alkenyl"). In some embodiments, an alkenyl group has 2 to 5 carbon atoms ("C _2-5 alkenyl"). In some embodiments, an alkenyl group has 2 to 4 carbon atoms ("C _2-4 alkenyl"). In some embodiments, an alkenyl group has 2 to 3 carbon atoms ("C _2-3 alkenyl"). In some embodiments, an alkenyl group has 2 carbon atoms ("C ₂ alkenyl"). The one or more carbon carbon double bonds can be internal (such as in 2- butenyl) or terminal (such as in 1-butenyl). Examples of C _2-4 alkenyl groups include ethenyl (C ₂ ), 1-propenyl (C ₃ ), 2-propenyl (C ₃ ), 1- butenyl (C ₄ ), 2-butenyl (C ₄ ), butadienyl (C ₄ ), and the like. Examples of C _2-6 alkenyl groups include the aforementioned C _2-4 alkenyl groups as well as pentenyl (C ₅ ), pentadienyl (C ₅ ), hexenyl (C ₆ ), and the like. Additional examples of alkenyl include heptenyl (C ₇ ), octenyl (C ₈ ), octatrienyl (C ₈ ), and the like. Unless otherwise specified, each instance of an alkenyl group is independently optionally substituted, i.e., unsubstituted (an "unsubstituted alkenyl") or substituted (a "substituted alkenyl") with one or more substituents e.g., for instance from 1 to 5 substituents, 1 to 3 substituents, or 1 substituent. In certain embodiments, the alkenyl group is unsubstituted C _2-10 alkenyl. In certain embodiments, the alkenyl group is substituted C _2-10 alkenyl.

"Alkynyl" refers to a radical of a straight-chain or branched hydrocarbon group having from 2 to 20 carbon atoms, one or more carbon-carbon triple bonds, and optionally one or more double bonds ("C _2-20 alkynyl"). In some embodiments, an alkynyl group has 2 to 10 carbon atoms ("C _2-10 alkynyl"). In some embodiments, an alkynyl group has 2 to 8 carbon atoms ("C _2-8 alkynyl"). In some embodiments, an alkynyl group has 2 to 6 carbon atoms ("C _2-6 alkynyl"). In some embodiments, an alkynyl group has 2 to 5 carbon atoms ("C _2-5 alkynyl"). In some embodiments, an alkynyl group has 2 to 4 carbon atoms ("C _2-4 alkynyl"). In some embodiments, an alkynyl group has 2 to 3 carbon atoms ("C _2-3 alkynyl"). In some embodiments, an alkynyl group has 2 carbon atoms ("C ₂ alkynyl"). The one or more carbon carbon triple bonds can be internal (such as in 2-butynyl) or terminal (such as in 1-butynyl). Examples of C _2-4 alkynyl groups include, without limitation, ethynyl (C ₂ ), 1-propynyl (C ₃ ), 2- propynyl (C ₃ ), 1-butynyl (C ₄ ), 2-butynyl (C ₄ ), and the like. Examples of C _2-6 alkenyl groups include the aforementioned C _2-4 alkynyl groups as well as pentynyl (C ₅ ), hexynyl (C ₆ ), and the like. Additional examples of alkynyl include heptynyl (C ₇ ), octynyl (C ₈ ), and the like. Unless otherwise specified, each instance of an alkynyl group is independently optionally substituted, i.e., unsubstituted (an "unsubstituted alkynyl") or substituted (a "substituted alkynyl") with on or more substituents; e.g., for instance from 1 to 5 substituents, 1 to 3 substituents, or 1 substituent. In certain embodiments, the alkynyl group is unsubstituted C _2-10 alkynyl. In certain embodiments, the alkynyl group is substituted C _2-10 alkynyl.

"Aryl" refers to a radical of a monocyclic or polycyclic (e.g., bicyclic or tricyclic) 4n+2 aromatic ring system (e.g., having 6, 10, or 14 p electrons shared in a cyclic array) having 6-1 ring carbon atoms and zero heteroatoms provided in the aromatic ring system ("C _6-14 aryl"). In some embodiments, an aryl group has six ring carbon atoms ("C ₆ aryl"; e.g., phenyl). In some embodiments, an aryl group has ten ring carbon atoms ("C ₁₀ aryl"; e.g., naphthyl such as 1- naphthyl and 2-naphthyl). In some embodiments, an aryl group has fourteen ring carbon atom ("C ₁₄ aryl"; e.g., anthracyl). "Aryl" also includes ring systems wherein the aryl ring, as define above, is fused with one or more carbocyclyl or heterocyclyl groups wherein the radical or point of attachment is on the aryl ring, and in such instances, the number of carbon atoms continue to designate the number of carbon atoms in the aryl ring system. Aryl groups include, but are not limited to, phenyl, naphthyl, indenyl, and tetrahydronaphthyl. Unless otherwise specified, each instance of an aryl group is independently optionally substituted, i.e., unsubstituted (an

"unsubstituted aryl") or substituted (a "substituted aryl") with one or more substituents. In certain embodiments, the aryl group is unsubstituted C _6-14 aryl. In certain embodiments, the aryl group is substituted C _6-14 aryl.

In certain embodiments, an aryl group substituted with one or more of groups selected from halo, C _1- C ₈ alkyl, C _1- C ₈ haloalkyl, cyano, hydroxy, C _1- C ₈ alkoxy, and amino.

Examples of representative substituted aryls include the following:

wherein one of R ⁵⁶ and R ⁵⁷ may be hydrogen and at least one of R ⁵⁶ and R ⁵⁷ is each

independently selected from C _1- C ₈ alkyl, C _1- C ₈ haloalkyl, 4-10 membered heterocyclyl, alkanoyl, C _1- C ₈ alkoxy, heteroaryloxy, alkylamino, arylamino, heteroarylamino, NR ⁵⁸ COR ⁵⁹ , NR ⁵⁸ SOR ⁵⁹ NR ⁵⁸ SO ₂ R ⁵⁹ , COOalkyl, COOaryl, CONR ⁵⁸ R ⁵⁹ , CONR ⁵⁸ OR ⁵⁹ , NR ⁵⁸ R ⁵⁹ ,

SO ₂ NR ⁵⁸ R ⁵⁹ , S-alkyl, SOalkyl, SO ₂ alkyl, Saryl, SOaryl, SO ₂ aryl; or R ⁵⁶ and R ⁵⁷ may be joined to form a cyclic ring (saturated or unsaturated) from 5 to 8 atoms, optionally containing one or more heteroatoms selected from the group N, O, or S. R ⁶⁰ and ^R61 are independently hydrogen, C _1- C ₈ alkyl, C ₁ -C ₄ haloalkyl, C ₃ -C ₁₀ cycloalkyl, 4-10 membered heterocyclyl, C ₆ -C ₁₀ aryl, substituted C ₆ -C ₁₀ aryl, 5-10 membered heteroaryl, or substituted 5-10 membered heteroaryl.

Other representative aryl groups having a fused heterocyclyl group include the following:

wherein each W is selected from C(R ⁶⁶ ) ₂ , NR ⁶⁶ , O, and S; and each Y is selected from carbonyl, NR ⁶⁶ , O and S; and R ⁶⁶ is independently hydrogen, C _1- C ₈ alkyl, C ₃ -C ₁₀ cycloalkyl, 4-10 membered heterocyclyl, C ₆ -C ₁₀ aryl, and 5-10 membered heteroaryl.

"Halo" or "halogen," independently or as part of another substituent, mean, unless otherwise stated, a fluorine (F), chlorine (Cl), bromine (Br), or iodine (I) atom. The term "halide" by itself or as part of another substituent, refers to a fluoride, chloride, bromide, or iodide atom. In certain embodiments, the halo group is either fluorine or chlorine.

"Haloalkyl" and "haloalkoxy" can include alkyl and alkoxy structures that are substituted with one or more halo groups or with combinations thereof. For example, the terms "fluoroalkyl" and "fluoroalkoxy" include haloalkyl and haloalkoxy groups, respectively, in which the halo is fluorine.

"Heteroaryl" refers to a radical of a 5-10 membered monocyclic or bicyclic 4n+2 aromatic ring system (e.g., having 6 or 10 p electrons shared in a cyclic array) having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen and sulfur ("5-10 membered heteroaryl"). In heteroaryl groups that contain one or more nitrogen atoms, the point of attachment can be a carbon or nitrogen atom, as valency permits. Heteroaryl bicyclic ring systems can include one or more heteroatoms in one or both rings. "Heteroaryl" includes ring systems wherein the heteroaryl ring, as defined above, is fused with one or more carbocyclyl or heterocyclyl groups wherein the point of attachment is on the heteroaryl ring, and in such instances, the number of ring members continue to designate the number of ring members in the heteroaryl ring system. "Heteroaryl" also includes ring systems wherein the heteroaryl ring, as defined above, is fused with one or more aryl groups wherein the point of attachment is either on the aryl or heteroaryl ring, and in such instances, the number of ring members designates the number of ring members in the fused (aryl/hetero aryl) ring system. Bicyclic heteroaryl groups wherein one ring does not contain a heteroatom (e.g., indolyl, quinolinyl, carbazolyl, and the like) the point of attachment can be on either ring, i.e., either the ring bearing a heteroatom (e.g., 2-indolyl) or the ring that does not contain a heteroatom (e.g., 5-indolyl).

In some embodiments, a heteroaryl group is a 5-10 membered aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-10 membered heteroaryl"). In some embodiments, a heteroaryl group is a 5-8 membered aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-8 membered heteroaryl"). In some embodiments, a heteroaryl group is a 5-6 membered aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-6 membered heteroaryl"). In some embodiments, the 5-6 membered heteroaryl has 1-3 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heteroaryl has 1-2 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heteroaryl has 1 ring heteroatom selected from nitrogen, oxygen, and sulfur. Unless otherwise specified, each instance of a heteroaryl group is

independently optionally substituted, i.e., unsubstituted (an "unsubstituted heteroaryl") or substituted (a "substituted heteroaryl") with one or more substituents. In certain embodiments, the heteroaryl group is unsubstituted 5-14 membered heteroaryl. In certain embodiments, the heteroaryl group is substituted 5-14 membered heteroaryl.

Exemplary 5-membered heteroaryl groups containing one heteroatom include, witho limitation, pyrrolyl, furanyl and thiophenyl. Exemplary 5-membered heteroaryl groups containing two heteroatoms include, without limitation, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, and isothiazolyl. Exemplary 5-membered heteroaryl groups containin three heteroatoms include, without limitation, triazolyl, oxadiazolyl, and thiadiazolyl. Exemplary 5- membered heteroaryl groups containing four heteroatoms include, without limitation, tetrazolyl. Exemplary 6-membered heteroaryl groups containing one heteroatom include, without limitation, pyridinyl. Exemplary 6-membered heteroaryl groups containing two heteroatoms include, without limitation, pyridazinyl, pyrimidinyl, and pyrazinyl. Exemplary 6-membered heteroaryl groups containing three or four heteroatoms include, without limitation, triazinyl and tetrazinyl, respectively. Exemplary 7-membered heteroaryl groups containing one heteroatom include, without limitation, azepinyl, oxepinyl, and thiepi Exemplary 5,6-bicyclic heteroaryl groups include, without limitation, indolyl, isoindolyl, indazolyl, benzotriazolyl,

benzothiophenyl, isobenzothiophenyl, benzofuranyl, benzoisofura benzimidazolyl, benzoxazolyl, benzisoxazolyl, benzoxadiazolyl, benzthiazolyl, benzisothiazolyl, benzthiadiazolyl, indolizinyl, and purinyl. Exemplary 6,6-bicyclic hetero groups include, without limitation, naphthyridinyl, pteridinyl, quinolinyl, isoquinolinyl, cinnolinyl, quinoxalinyl, phthalazinyl, and quinazolinyl.

Examples of representative heteroaryls include the following formulae:

wherein each Y is selected from carbonyl, N, NR ⁶⁵ , O, and S; and R ⁶⁵ is independently hydrogen, C ₁ -C ₈ alkyl, C ₃ -C ₁₀ cycloalkyl, 4-10 membered heterocyclyl, C ₆ -C ₁₀ aryl, and 5-10 membered heteroaryl.

"Carbocyclyl" or "carbocyclic" refers to a radical of a non-aromatic cyclic hydrocarbon group having from 3 to 10 ring carbon atoms ("C _3-10 carbocyclyl") and zero heteroatoms in the non-aromatic ring system. In some embodiments, a carbocyclyl group has 3 to 8 ring carbon atoms ("C _3-8 carbocyclyl"). In some embodiments, a carbocyclyl group has 3 to 6 ring carbon atoms ("C _3-6 carbocyclyl"). In some embodiments, a carbocyclyl group has 3 to 6 ring carbon atoms ("C _3-6 carbocyclyl"). In some embodiments, a carbocyclyl group has 5 to 10 ring carbon atoms ("C _5-10 carbocyclyl"). Exemplary C _3-6 carbocyclyl groups include, without limitation, cyclopropyl (C ₃ ), cyclopropenyl (C ₃ ), cyclobutyl (C ₄ ), cyclobutenyl (C ₄ ), cyclopentyl (C ₅ ), cyclopentenyl (C ₅ ), cyclohexyl ( C ₆ ), cyclohexenyl C ₆ ), cyclohexadienyl (C ₆ ), and the like. Exemplary C _3-6 carbocyclyl groups include, without limitation, the aforementioned C _3-6 carbocyclyl groups as well as cycloheptyl (C ₇ ), cycloheptenyl (C ₇ ), cycloheptadienyl (C ₇ ), cycloheptatrienyl (C ₇ ), cyclooctyl (C ₈ ), cyclooctenyl (C ₈ ), bicyclo[2.2.1]heptanyl (C ₇ ), bicyclo[2.2.2]octanyl (C ₈ ), and the like. Exemplary C _3-10 carbocyclyl groups include, without limitation, the aforementioned C _3-8 carbocyclyl groups as well as cyclononyl (C ₉ ), cyclononenyl (C ₉ ), cyclodecyl (C ₁₀ ), cyclodecenyl (C ₁₀ ), octahydro-lH-indenyl (C ₉ ), decahydronaphthalenyl (C ₁₀ ), spiro[4.5]decanyl (C ₁₀ ), and the like. As the foregoing examples illustrate, in certain embodiments, the carbocyclyl group is either monocyclic ("monocyclic carbocyclyl") or contain a fused, bridged or spiro ring system such as a bicyclic system ("bicyclic carbocyclyl") and can be saturated or can be partially unsaturated. "Carbocyclyl" also includes ring systems wherein the carbocyclyl ring, as defined above, is fused with one or more aryl or heteroaryl groups wherein the point of attachment is on the carbocyclyl ring, and in such instances, the number of carbons continue to designate the number of carbons in the carbocyclic ring system. Unless otherwise specified, each instance of a carbocyclyl group is independently optionally substituted, i.e., unsubstituted (an "unsubstituted carbocyclyl") or substituted (a "substituted carbocyclyl") with one or more substituents. In certain embodiments, the carbocyclyl group is unsubstituted C ₃ _ ₁₀ carbocyclyl. In certain embodiments, the carbocyclyl group is a substituted C _{3- 10} carbocyclyl.

In some embodiments, "carbocyclyl" is a monocyclic, saturated carbocyclyl group having from 3 to 10 ring carbon atoms (" C ₃ -C ₁₀ cycloalkyl"). In some embodiments, a cycloalkyl group has 3 to 8 ring carbon atoms ("C _3-8 cycloalkyl"). In some embodiments, a cycloalkyl group has 3 to 6 ring carbon atoms ("C _3-6 cycloalkyl"). In some embodiments, a cycloalkyl group has 5 to 6 ring carbon atoms ("C _5-6 , cycloalkyl"). In some embodiments, a cycloalkyl group has 5 to 10 ring carbon atoms ("C ₅ 10 cycloalkyl"). Examples of C _5-6 , cycloalkyl groups include cyclopentyl (C ₅ ) and cyclohexyl (C ₅ ). Examples of C _3-6 cycloalkyl groups include the aforementioned C _5-6 cycloalkyl groups as well as cyclopropyl (C ₃ ) and cyclobutyl (C ₄ ). Examples of C _3-8 cycloalkyl groups include the aforementioned C _3-8 cycloalkyl groups as well as cycloheptyl (C7) and cyclooctyl (C ₈ ). Unless otherwise specified, each instance of a cycloalkyl group is independently unsubstituted (an "unsubstituted cycloalkyl") or substituted (a "substituted cycloalkyl") with one or more substituents. In certain embodiments, the cycloalkyl group is unsubstituted C _{3- 10} cycloalkyl. In certain embodiments, the cycloalkyl group is substituted C _{3- 10} cycloalkyl.

"Heterocyclyl" or "heterocyclic" refers to a radical of a 3- to 10-membered non-aromatic ring system having ring carbon atoms and 1 to 4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, sulfur, boron, phosphorus, and silicon ("3-10 membered heterocyclyl"). In heterocyclyl groups that contain one or more nitrogen atoms, the point of attachment can be a carbon or nitrogen atom, as valency permits. A heterocyclyl group can either be monocyclic ("monocyclic heterocyclyl") or a fused, bridged or spiro ring system such as a bicyclic system ("bicyclic heterocyclyl"), and can be saturated or can be partially unsaturated. Heterocyclyl bicyclic ring systems can include one or more heteroatoms in one or both rings. "Heterocyclyl" also includes ring systems wherein the heterocyclyl ring, as defined above, is fused with one or more carbocyclyl groups wherein the point of attachment is either on the carbocyclyl or heterocyclyl ring, or ring systems wherein the heterocyclyl ring, as defined above, is fused with one or more aryl or heteroaryl groups, wherein the point of attachment is on the heterocyclyl ring, and in such instances, the number of ring members continue to designate the number of ring members in the heterocyclyl ring system. Unless otherwise specified, each instance of heterocyclyl is independently optionally substituted, i.e., unsubstituted (an

"unsubstituted heterocyclyl") or substituted (a "substituted heterocyclyl") with one or more substituents. In certain embodiments, the heterocyclyl group is unsubstituted 3-10 membered heterocyclyl. In certain embodiments, the heterocyclyl group is substituted 3-10 membered heterocyclyl.

In some embodiments, a heterocyclyl group is a 5-10 membered non-aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, sulfur, boron, phosphorus, and silicon ("5-10 membered heterocyclyl"). In some embodiments, a heterocyclyl group is a 5-8 membered non- aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-8 membered heterocyclyl"). In some embodiments, a heterocyclyl group is a 5-6 membered non-aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-6 membered heterocyclyl"). In some embodiments, the 5-6 membered heterocyclyl has 1-3 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heterocyclyl has 1-2 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heterocyclyl has one ring heteroatom selected from nitrogen, oxygen, and sulfur.

Exemplary 3-membered heterocyclyl groups containing one heteroatom include, without limitation, azirdinyl, oxiranyl, thiorenyl. Exemplary 4-membered heterocyclyl groups containing one heteroatom include, without limitation, azetidinyl, oxetanyl and thietanyl. Exemplary 5- membered heterocyclyl groups containing one heteroatom include, without limitation, tetrahydrofuranyl, dihydrofuranyl, tetrahydrothiophenyl, dihydrothiophenyl, pyrrolidinyl, dihydropyrrolyl and pyrrolyl-2,5-dione. Exemplary 5-membered heterocyclyl groups containing two heteroatoms include, without limitation, dioxolanyl, oxasulfuranyl, disulfuranyl, and oxazolidin-2-one. Exemplary 5-membered heterocyclyl groups containing three heteroatoms include, without limitation, triazolinyl, oxadiazolinyl, and thiadiazolinyl. Exemplary 6- membered heterocyclyl groups containing one heteroatom include, without limitation, piperidinyl, tetrahydropyranyl, dihydropyridinyl, and thianyl. Exemplary 6- membered heterocyclyl groups containing two heteroatoms include, without limitation, piperazinyl, morpholinyl, dithianyl, dioxanyl. Exemplary 6-membered heterocyclyl groups containing two heteroatoms include, without limitation, triazinanyl. Exemplary 7-membered heterocyclyl groups containing one heteroatom include, without limitation, azepanyl, oxepanyl and thiepanyl. Exemplary 8-membered heterocyclyl groups containing one heteroatom include, without limitation, azocanyl, oxecanyl and thiocanyl. Exemplary 5-membered heterocyclyl groups fused to a Ce aryl ring (also referred to herein as a 5,6-bicyclic heterocyclic ring) include, without limitation, indolinyl, isoindolinyl, dihydrobenzofuranyl, dihydrobenzo thienyl, benzoxazolinonyl, and the like. Exemplary 6-membered heterocyclyl groups fused to an aryl ring (also referred to herein as a 6,6-bicyclic heterocyclic ring) include, without limitation, tetrahydroquinolinyl, tetrahydroisoquinolinyl, and the like.

Particular examples of heterocyclyl groups are shown in the following illustrative examples:

wherein each W is selected from CR ⁶⁷ , C(R ⁶⁷ )2, NR ⁶⁷ , O, and S; and each Y is selected from NR ⁶⁷ , O, and S; and R ⁶⁷ is independently hydrogen, C _1- C ₈ alkyl, C ₃ -C ₁₀ cycloalkyl, 4-10 membered heterocyclyl, C ₆ -C ₁₀ aryl, and 5-10-membered heteroaryl. These heterocyclyl rings may be optionally substituted with one or more groups selected from the group consisting of acyl, acylamino, acyloxy, alkoxy, alkoxycarbonyl, alkoxycarbonylamino, amino, substituted amino, aminocarbonyl (e.g., amido), aminocarbonylamino, aminosulfonyl, sulfonylamino, aryl, aryloxy, azido, carboxyl, cyano, cycloalkyl, halogen, hydroxy, keto, nitro, thiol, -S-alkyl, -S aryl, -S(O)-alkyl, -S(O)-aryl, -S(O) ₂ -alkyl, and -S(O) ₂ -aryl. Substituting groups include carbonyl or thiocarbonyl which provide, for example, lactam and urea derivatives.

"Acyl" refers to a radical-C(O)R , where R is hydrogen, substituted or unsubstitued alkyl, substituted or unsubstitued alkenyl, substituted or unsubstitued alkynyl, substituted or unsubstitued carbocyclyl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted aryl, or substituted or unsubstitued heteroaryl, as defined herein. "Alkanoyl" is an acyl group wherein R is a group other than hydrogen. Representative acyl groups include, but are not limited to, formyl (-CHO), acetyl (-C(=O)CH ₃ ), cyclohexylcarbonyl, cyclohexylmethylcarbonyl, benzoyl (-C(=O)Ph), benzylcarbonyl (-C(=O)CH ₂ Ph),— C(O)-C _1- C ₈ alkyl, -C(O)-(CH ₂ ) _t (C ₆ -C ₁₀ aryl), -C(O)-(CH ₂ ) _t (5-10 membered heteroaryl), -C(O)- (CH2) _t ( C _{3- 10} cycloalkyl), and -C(O)- (CH ₂ ) _t (4-10 membered heterocyclyl), wherein t is an integer from 0 to 4. In certain

embodiments, R is C _1- C ₈ alkyl, substituted with halo or hydroxy; or C ₃ -C ₁₀ cycloalkyl, 4-10 membered heterocyclyl, C ₆ -C ₁₀ aryl, arylalkyl, 5-10 membered heteroaryl or heteroarylalkyl, each of which is substituted with unsubstituted C ₁ -C ₄ alkyl, halo, unsubstituted C ₁ -C ₄ alkoxy, unsubstituted C ₁ -C ₄ haloalkyl, unsubstituted C ₁ -C ₄ hydroxyalkyl, or unsubstituted C ₁ -C ₄ haloalkoxy or hydroxy.

"Acylamino" refers to a radical-NR ²² C(O)R ²³ , where each instance of R ²² and R ²³ is independently hydrogen, substituted or unsubstitued alkyl, substituted or unsubstitued alkenyl, substituted or unsubstitued alkynyl, substituted or unsubstitued carbocyclyl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted aryl, or substituted or unsubstitued heteroaryl,, as defined herein, or R is an amino protecting group. Exemplary "acylamino" groups include, but are not limited to, formylamino, acetylamino, cyclohexylcarbonylamino, cyclohexylmethyl-carbonylamino, benzoylamino and benzylcarbonylamino. Particular exemplary "acylamino" groups are -NR ²⁴ C(O)-C _1- C ₈ alkyl, -NR ²⁴ C(O)-(CH ₂ ) _t (C ₆ -C ₁₀ aryl), - NR ²⁴ C(O)-(CH ₂ ),(5- 10 membered heteroaryl), -NR ²⁴ C(O)-(CH ₂ ) _t (C ₃ -C ₁₀ cycloalkyl), and - NR C(O)-(CH ₂ ) _t (4-10 membered heterocyclyl), wherein t is an integer from 0 to 4, and each R independently represents hydrogen or C _1- C ₈ alkyl. In certain embodiments, R is H, C _1- C ₈ alkyl, substituted with halo or hydroxy; C ₃ -C ₁₀ cycloalkyl, 4-10 membered heterocyclyl, C ₆ -C ₁₀ aryl, arylalkyl, 5-10 membered heteroaryl or heteroarylalkyl, each of which is substituted with unsubstituted C ₁ -C ₄ alkyl, halo, unsubstituted C ₁ -C ₄ alkoxy, unsubstituted C ₁ -C ₄ haloalkyl, unsubstituted C ₁ -C ₄ hydroxyalkyl, or unsubstituted C ₁ -C ₄ haloalkoxy or hydroxy; and R ²⁶ is H, C _1- C ₈ alkyl, substituted with halo or hydroxy; C ₃ -C ₁₀ cycloalkyl, 4-10- membered heterocyclyl, C ₆ -C ₁₀ aryl, arylalkyl, 5-10-membered heteroaryl or heteroarylalkyl, each of which is substituted with unsubstituted C ₁ -C ₄ alkyl, halo, unsubstituted C ₁ -C ₄ alkoxy, unsubstituted C ₁ -C ₄ haloalkyl, unsubstituted C ₁ -C ₄ hydroxyalkyl, or unsubstituted C ₁ -C ₄ haloalkoxy or hydroxy; provided at least one of R ²⁵ and R ²⁶ is other than H.

"Acyloxy" refers to a radical -OC(O)R , where R is hydrogen, substituted or unsubstitued alkyl, substituted or unsubstitued alkenyl, substituted or unsubstitued alkynyl, substituted or unsubstitued carbocyclyl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted aryl, or substituted or unsubstitued heteroaryl, as defined herein. Representative examples include, but are not limited to, formyl, acetyl, cyclohexylcarbonyl,

cyclohexylmethylcarbonyl, benzoyl, and benzylcarbonyl. In certain embodiments, R is C _1- C ₈ alkyl, substituted with halo or hydroxy; C ₃ -C ₁₀ cycloalkyl, 4-10-membered heterocyclyl, C ₆ -C ₁₀ aryl, arylalkyl, 5-10-membered heteroaryl or heteroarylalkyl, each of which is substituted with unsubstituted C ₁ -C ₄ alkyl, halo, unsubstituted C ₁ -C ₄ alkoxy, unsubstituted C ₁ -C ₄ haloalkyl, unsubstituted C ₁ -C ₄ hydroxyalkyl, or unsubstituted C ₁ -C ₄ haloalkoxy or hydroxy.

"Alkoxy" refers to the group -OR where R is substituted or unsubstituted alkyl, substituted or unsubstitued alkenyl, substituted or unsubstitued alkynyl, substituted or

unsubstitued carbocyclyl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted aryl, or substituted or unsubstitued heteroaryl. Particular alkoxy groups are methoxy, ethoxy, n- propoxy, isopropoxy, n-butoxy, tert-butoxy, sec-butoxy, n-pentoxy, n-hexoxy, and 1,2- dimethylbutoxy. Particular alkoxy groups are lower alkoxy, i.e., with between 1 and 6 carbon atoms. Further particular alkoxy groups have between 1 and 4 carbon atoms.

In certain embodiments, R is a group that has 1 or more substituents, for instance from 1 to 5 substituents, and particularly from 1 to 3 substituents, in particular 1 substituent, selected from the group consisting of amino, substituted amino, C ₆ -C ₁₀ aryl, aryloxy, carboxyl, cyano, C ₃ - C ₁₀ cycloalkyl, 4-10 membered heterocyclyl, halogen, 5-10 membered heteroaryl, hydroxy, nitro, thioalkoxy, thioaryloxy, thiol, alkyl-S(O)-, aryl-S(O)-, alkyl-S(O) ₂ - and aryl-S(O) ₂ - Exemplary "substituted alkoxy" groups include, but are not limited to, -O-(CH ₂ ) _t (C ₆ -C ₁₀ aryl), -O-(CH ₂ ) _t (5- 10 memberedheteroaryl),-O-(CH ₂ ) _t (C ₃ -C ₁ o cycloalkyl), and -O-(CH ₂ ) _t (4- 10 membered heterocyclyl), wherein t is an integer from 0 to 4 and any aryl, heteroaryl, cycloalkyl or heterocyclyl groups present, may themselves be substituted by unsubstituted C ₁ -C ₄ alkyl, halo, unsubstituted C ₁ -C ₄ alkoxy, unsubstituted C ₁ -C ₄ haloalkyl, unsubstituted C ₁ -C ₄ hydroxyalkyl, or unsubstituted C ₁ -C ₄ haloalkoxy or hydroxy. Particular exemplary‘substituted alkoxy’ groups are -OCF ₃ ,-OCH ₂ CF ₃ ,-OCH ₂ Ph,-OCH ₂ -cyclopropyl, -OCH ₂ CH ₂ OH, and - OCH ₂ CH ₂ Nme ₂ .

"Amino" refers to the radical-NH ₂ .

"Substituted amino" refers to an amino group of the formula-N(R ) ₂ wherein R is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstitued alkenyl, substituted or unsubstitued alkynyl, substituted or unsubstitued carbocyclyl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted aryl, substituted or unsubstitued heteroaryl, or an amino protecting group, wherein at least one of R is not a hydrogen. In certain embodiments, each R is independently selected from hydrogen, C ₁ -C ₈ alkyl, C ₃ -C ₈ alkenyl, C ₃ -C ₈ alkynyl, C ₆ - C ₁₀ aryl, 5-10 membered heteroaryl, 4-10 membered heterocyclyl, or C ₃ -C ₁₀ cycloalkyl; or C ₁ -C ₈ alkyl, substituted with halo or hydroxy; C ₃ -C ₈ alkenyl, substituted with halo or hydroxy; C ₃ -C ₈ alkynyl, substituted with halo or hydroxy, or -(CH ₂ ) _t (C ₆ -CI _O aryl), -(CH ₂ ) _t (5-10 membered heteroaryl), -(CH ₂ ) _t (C ₃ -CI _O cycloalkyl), or -(CH ₂ ) _t (4-10 membered heterocyclyl), wherein t is an integer between 0 and 8, each of which is substituted by unsubstituted C ₁ -C ₄ alkyl, halo, unsubstituted C ₁ -C ₄ alkoxy, unsubstituted C ₁ -C ₄ haloalkyl, unsubstituted C ₁ -C ₄ hydroxyalkyl, or unsubstituted C ₁ -C ₄ haloalkoxy or hydroxy; or both R groups are joined to form an alkylene group.

Exemplary "substituted amino" groups include, but are not limited to, -NR ³⁹ -C ₁ -C ₈ alkyl, -NR ³⁹ -(CH 2) _t (C ₆ -CI _O aryl), -NR ³⁹ -(CH ₂ ) _t (5-10 membered heteroaryl), -NR ³⁹ - (CH ₂ ) _t (C ₃ -C ₁₀ cycloalkyl), and -NR -(CH ₂ ) _t (4-10 membered heterocyclyl), wherein t is an integer from 0 to 4, for instance 1 or 2, each R independently represents hydrogen or C ₁ -C ₈ alkyl; and any alkyl groups present, may themselves be substituted by halo, substituted or unsubstituted amino, or hydroxy; and any aryl, heteroaryl, cycloalkyl, or heterocyclyl groups present, may themselves be substituted by unsubstituted C ₁ -C ₄ alkyl, halo, unsubstituted C ₁ -C ₄ alkoxy, unsubstituted C ₁ -C ₄ haloalkyl, unsubstituted C ₁ -C ₄ hydroxyalkyl, or unsubstituted C ₁ -C ₄ haloalkoxy or hydroxy. For the avoidance of doubt the term‘substituted amino’ includes the groups alkylamino, substituted alkylamino, alkylarylamino, substituted alkylarylamino, arylamino, substituted arylamino, dialkylamino, and substituted dialkylamino as defined below. Substituted amino encompasses both monosubstituted amino and disubstituted amino groups.

"Azido" refers to the radical-N3.

"Carbamoyl" or "amido" refers to the radical-C(O)NH ₂ .

"Substituted carbamoyl" or "substituted amido" refers to the radical -C(O)N(R ⁶² ) ₂ wherein each R ⁶² is independently hydrogen, substituted or unsubstituted alkyl, substituted or unsubstitued alkenyl, substituted or unsubstitued alkynyl, substituted or unsubstitued

carbocyclyl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted aryl, substituted or unsubstitued heteroaryl, or an amino protecting group, wherein at least one of R ⁶² is not a hydrogen. In certain embodiments, R ⁶² is selected from H, C _1- C ₈ alkyl, C ₃ -C ₁₀ cycloalkyl, 4-10 membered heterocyclyl, C ₆ -C ₁₀ aryl, and 5-10 membered heteroaryl; or C _1- C ₈ alkyl substituted with halo or hydroxy; or C ₃ -C ₁₀ cycloalkyl, 4-10 membered heterocyclyl, C ₆ - C ₁₀ aryl, or 5-10 membered heteroaryl, each of which is substituted by unsubstituted C ₁ -C ₄ alkyl, halo, unsubstituted C ₁ -C ₄ alkoxy, unsubstituted C ₁ -C ₄ haloalkyl, unsubstituted C ₁ -C ₄

hydroxyalkyl, or unsubstituted C ₁ -C ₄ haloalkoxy or hydroxy; provided that at least one R ⁶² is other than H.

"Carboxy" refers to the radical -C(O)OH.

"Cyano" refers to the radical-CN.

"Hydroxy" refers to the radical-OH.

"Nitro" refers to the radical -NO ₂ .

"Ethenyl" refers to substituted or unsubstituted-(C=C)-. "Ethylene" refers to substituted or unsubstituted -(C-C)-. "Ethynyl" refers to ·

"Nitrogen-containing heterocyclyl" group means a 4- to 7- membered non-aromatic cyclic group containing at least one nitrogen atom, for example, but without limitation, morpholine, piperidine {e.g. 2-piperidinyl, 3-piperidinyl and 4-piperidinyl), pyrrolidine (e.g. 2- pyrrolidinyl and 3-pyrrolidinyl), azetidine, pyrrolidone, imidazoline, imidazolidinone, 2- pyrazoline, pyrazolidine, piperazine, and N-alkyl piperazines such as N-methyl piperazine.

Particular examples include azetidine, piperidone and piperazone.

Alkyl, alkenyl, alkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl groups, as defined herein, are optionally substituted, e.g., "substituted" or "unsubstituted" alkyl, "substituted" or "unsubstituted" alkenyl, "substituted" or "unsubstituted" alkynyl, "substituted" or "unsubstituted" carbocyclyl, "substituted" or "unsubstituted" heterocyclyl, "substituted" or "unsubstituted" aryl or "substituted" or "unsubstituted" heteroaryl group). In general, the term "substituted", whether preceded by the term "optionally" or not, means that at least one hydrogen present on a group ( e.g., a carbon or nitrogen atom) is replaced with a permissible substituent, e.g., a substituent which upon substitution results in a stable compound, e.g., a compound which does not spontaneously undergo transformation such as by rearrangement, cyclization, elimination, or other reaction. Unless otherwise indicated, a "substituted" group has a substituent at one or more substitutable positions of the group, and when more than one position in any given structure is substituted, the substituent is either the same or different at each position. The term "substituted" is contemplated to include substitution with all permissible substituents of organic compounds, any of the substituents described herein that results in the formation of a stable compound. The present invention contemplates any and all such combinations in order to arrive at a stable compound. For purposes of this invention, heteroatoms such as nitrogen may have hydrogen substituents and/or any suitable substituent as described herein which satisfy the valencies of the heteroatoms and results in the formation of a stable moiety.

Exemplary carbon atom substituents include, but are not limited to, halogen, -CN, - NO ₂ , -N ₃ , -SO ₂ H, -SO ₃ H, -OH, -OR ^aa ,-ON(R ^bb ) ₂ , -N(R ^bb ) ₂ ,-N(R ^bb ) ₃ ⁺ X-,- (OR ^cc )R ^bb , - SH, -SR ^aa , - SSR ^cc ,-C(=O)R ^aa ,-CO ₂ H, -CHO, -C(OR ^cc ) ₂ , -CO ₂ R ^aa , -OC(=O)R ^aa ,-OCO ₂ R ^aa , -C(=O)N(R ^bb ) ₂ ,- -OC(=O)N(R ^bb ) ₂ ,-NR ^bb C(=O)R ^aa ,-NR ^bb CO ₂ R ^aa ,-NR ^bb C(=O)N(R ^bb ) ₂ ,- C(=NR ^bb )R ^aa , - C(=NR ^bb )OR ^aa , -OC(=NR ^bb )R ^aa , -OC(=NR ^bb )OR ^aa , -C(=NR ^bb )N(R ^bb ) ₂ , - OC(=NR ^bb )N(R ^bb ) ₂ , - NR ^bb C(=NR ^bb )N(R ^bb ) ₂ ,-C(=O)NR ^bb SO ₂ R ^aa , -NR ^hh SO ₂ R ^aa , -SO ₂ N(R ^bb ) ₂ , -SO ₂ R ^aa ,-SO ₂ OR ^aa ,- OSO ₂ R ^aa ,-S(=O)R ^aa ,- OS(=O)R ^aa ,-Si(R ^aa ) ₃ ,-Osi(R ^aa ) ₃ -C(=S)N(R ^bb ) ₂ , -C(=O)SR ^aa ,-C(=S)SR ^aa ,- SC(=S)SR ^aa ,-SC(=O)SR ^aa ,-OC(=O)SR ^aa ,-SC(=O)OR ^aa ,- SC(=O)R ^aa , -P(=O) ₂ R ^aa ,-OP(=O) ₂ R ^aa ,- P(=O)(R ^aa ) ₂ , -OP(=O)(R ^aa ) ₂ ,-OP(=O)(OR ^cc ) ₂ ,- P(=O) ₂ N(R ^bb ) ₂ ,-OP(=O) ₂ N(R ^bb ) ₂ ,-P(=O)(NR ^bb ) ₂ ,- OP(=O)(NR ^bb ) ₂ , -NR ^bb P(=O)(OR ^cc ) ₂ ,- NR ^bb P(=O)(NR ^bb ) ₂ , -P(R ^CC ) ₂ , -P(R ^CC ) ₃ , -OP(R ^cc ) ₂ , - OP(R ^cc ) ₃ , -B(R ^aa ) ₂ , -B(OR ^cc ) ₂ , - BR ^aa (OR ^cc ), C ₁ -C ₁₀ alkyl, C ₁ -C ₁₀ perhaloalkyl, C ₂ -C ₁₀ alkenyl, C ₂ -C ₁₀ alkynyl, C ₃ -C ₁₀ carbocyclyl, 3- 14 membered heterocyclyl, C _6-14 aryl, and 5-14 membered heteroaryl, wherein each alkyl, alkenyl, alkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R ^dd groups;

each instance of is, independently, selected from C ₁ -C ₁₀ alkyl, C ₁ -C ₁₀ perhaloalkyl, C _2-10 alkenyl, C _2-10 alkynyl, C _3-10 carbocyclyl, 3-14 membered heterocyclyl, C _6-14 aryl, and 5-14 membered heteroaryl, or two R ^aa groups are joined to form a 3-14 membered heterocyclyl or 5- 14 membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R ^dd groups;

each instance of R ^bb is, independently, selected from hydrogen, -OH, -OR ^aa , -N(R ^cc ) ₂ ,- CN, -C(=O)R ^aa ,-C(=O)N(R ^cc ) ₂ , -CO ₂ R ^aa , -SO ₂ R ^aa ,-C(=NR ^cc )OR ^aa ,-C(=NR ^cc )N(R ^cc ) ₂ ,- SO ₂ N(R ^cc ) ₂ , -SO ₂ R ^cc -SO ₂ OR ^cc -SOR ^cc , -C(=S)N(R ^cc ) ₂ , -C(=O)SR ^cc , -C(=S)SR ^cc , - R(=O) ₂ R ^aa ,- P(=O)(R ^aa ) ₂ ,-P(=O) ₂ N(R ^cc ) ₂ , -P(=O)(NR ^cc ) ₂ , CHO alkyl, C ₁ -C ₁₀ perhaloalkyl, C _2-10 alkenyl, C _2-10 alkynyl, C _3-10 carbocyclyl, 3-14 membered heterocyclyl, C _6-14 aryl, and 5-14 membered heteroaryl, or two R ^bb groups are joined to form a 3-14 membered heterocyclyl or 5- 14 membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R ^dd groups;

each instance of R ^cc is, independently, selected from hydrogen, C ₁ -C ₁₀ alkyl, C ₁ -C ₁₀ perhaloalkyl, C _2-10 alkenyl, C _2-10 alkynyl, C _{3- 10} carbocyclyl, 3-14 membered heterocyclyl, Ce-u aryl, and 5-14 membered heteroaryl, or two R ^cc groups are joined to form a 3-14 membered heterocyclyl or 5-14 membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R ^dd groups;

each instance of R ^dd is, independently, selected from halogen, -CN, -NO ₂ , -N ₃ , -SO ₂ H, - SO3H, -OH, -OR ^ee ,-ON(R ^ff ) ₂ , -N(R ^ff ) ₂ ,-N(R ^ff ) ₃ ⁺ X-, -N((OR ^ee )R ^ff ,-SH, -SR ^ee ,-SSR ^ee , - C(=O)R ^ee ,- CO ₂ H, -CO ₂ R ^ee , -OC(=O)R ^ee , -OCO ₂ R ^ee ,-C(=O)N(R ^ff ) ₂ , -OC(=O)N(R ^ff ) ₂ , - NR ^ff C(=O)R ^ee , - NR ^ff CO ₂ R ^ee , -NR ^ff C(=O)N(R ^ff ) ₂ , -C(=NR ^ff )OR ^ee , -OC(=NR ^ff )R ^ee , - OC(=NR ^ff )OR ^ee , - C(=NR ^ff )N(R ^ff ) ₂ ,-OC(=NR ^ff )N(R ^ff ) ₂ , -NR ^ff C(=NR ^ff )N(R ^ff ) ₂ ,-NR ^ff SO ₂ R ^ee ,- SO ₂ N(R ^ff ) ₂ ,-SO ₂ R ^ee ,- SO ₂ OR ^ee , -OSO ₂ R ^ee ,-S(=O)R ^ee ,-Si(R ^ee ) ₃ ,-0si(R ^ee ) ₃ , -C(=S)N(R ^ff ) ₂ ,- C(=O)SR ^ee , -C(=S)SR ^ee , - SC(=S)SR ^ee , -P(=O) ₂ R ^ee , -P(=O)(R ^ee ) ₂ ,-OP(=O)(R ^ee ) ₂ , - OP(=O)(OR ^ee ) ₂ , C _1-3 , alkyl,

perhaloalkyl, C _2-6 alkenyl, C _2-6 alkynyl, C _{3- 10} carbocyclyl, 3-10 membered heterocyclyl, C _{6- 10} aryl, 5-10 membered heteroaryl, wherein each alkyl, alkenyl, alkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R _gg groups;

each instance of R ^ee is, independently, selected from C _1-3 , alkyl, C _1-3 , perhaloalkyl, C _2-6 alkenyl, C _2-6 alkynyl, C _{3- 10} carbocyclyl, C _6-10 aryl, 3-10 membered heterocyclyl, and 3-10 membered heteroaryl, wherein each alkyl, alkenyl, alkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R _gg groups; each instance of R ff is, independently, selected from hydrogen, C _1-6 alkyl, C _1-6 perhaloalkyl, C _2-6 alkenyl, C _2-6 alkynyl, C _{3- 10} carbocyclyl, 3-10 membered heterocyclyl, C _6-10 aryl and 5-10 membered heteroaryl, or two R ^ff groups are joined to form a 3-14 membered heterocyclyl or 5-14 membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R _gg groups; and

each instance of R _gg is, independently, halogen, -CN, -NO2, -N3, -SO2H, -SO3H, -OH, - OC _1-6 alkyl, -ON(C _1-6 alkyl) ₂ , -N(C _1-6 alkyl) ₂ , -N(C _1-6 alkyl) ₃ ⁺ X- NH(C _1-6 alkyl) ₂ ⁺ X- NH ₂ (C _1-6 alkyl) ⁺ X-, -NH ₃ ⁺ X , -N(OC _1-6 alkyl)(C ₁ _ ₆ alkyl), -N (OH)(C _1-6 alkyl), -NH(OH), - SH, -4SC _1-6 alkyl, -SS(C ₁ _ ₆ alkyl), -C(=O)(C ₁ _ ₆ alkyl), -CO ₂ H, -CO ₂ (C ₁ - ₆ alkyl), -OC(=O)(C ₁ _ ₆ alkyl), - OCO ₂ (C _1-6 alkyl), -C(=O)NH ₂ , -C(=O)N(C ₁ _ ₆ alkyl) ₂ , -OC(=O)NH(C _1-6 alkyl), - NHC(=O)( C _1-6 alkyl), -N(C _1-6 alkyl)C(=O)( C ₁ _ ₆ alkyl), -NHCO ₂ (C ₁ _ ₆ alkyl), -NHC(=O)N(C ₁ _ ₆ alkyl) ₂ ,- NHC(=O)NH(CI_ ₆ alkyl), -NHC(=O)NH ₂ , -C(=NH)0(C ₁ _ ₆ alkyl), -OC(=NH)(C _1-6 alkyl), - OC(=NH)OC ₁ _ ₆ alkyl, -C(=NH)N (C ₁ _ ₆ alkyl) ₂ , -C(=NH)NH(C _1-6 alkyl), -C(=NH)NH ₂ , - OC(=NH)N(C _1-6 alkyl) ₂ ,-OC(NH)NH(C _1-6 alkyl), -OC(NH)NH ₂ ,-NHC(NH)N(C _1-6 alkyl) ₂ ,- NHC(=NH)NH ₂ , -NHSO ₂ (C _1-6 alkyl), -SO ₂ N(C ₁ _ ₆ alkyl) ₂ , -SO ₂ NH(C ₁ _ ₆ alkyl), -SO ₂ NH ₂ ,- SO2C ₁ -6 alkyl, -SO ₂ OC _1-6 alkyl, -OSO ₂ C _1-6 alkyl, -SOC _1-6 alkyl, -Si(C ₁ _ ₆ alkyl) ₃ , -Osi(C ₁ _ ₆ alkyl) ₃ -C(=S)N(C ₁ _ ₆ alkyl) ₂ , C(=S)NH(C _1-6 alkyl), C(=S)NH ₂ , -C(=O)S(C ₁ _ ₆ alkyl), - C(=S)SC ₁ _ ₆ alkyl, -SC(=S)SC ₁ _ ₆ alkyl , -P(=O) ₂ (C _w alkyl), -P(=O)(C _1-6 alkyl) ₂ , -OP(=O)(C _1-6 alkyl) ₂ , - OP(=O)(OC _1-6 alkyl) ₂ , C _1-6 alkyl, C _1-6 perhaloalkyl, C _2-6 alkenyl, C _2-6 alkynyl, C _3-10 carbocyclyl, C _6-10 aryl, 3-10 membered heterocyclyl, 5-10 membered heteroaryl; wherein X- is a counterion.

Additional substituents are described in, for example, International Publication Nos. WO 2013/036835, WO 2013/056181, WO 2013/112605, WO 2013/188792, WO 2014/031792, WO 2014/100228, WO 2014/160441, WO 2014/160480, WO 2014/169831, WO 2014/169832, WO 2014/169833, WO 2014/169836, WO 2015/010054, WO 2015/027227, WO 2015/180679, WO 2015/195962, WO 2015/195967, WO 2016/040322, WO 2016/057713, WO 2016/061527, WO 2016/061537, WO 2016/082789, WO 2016/123056, WO 2016/134301, WO 2016/164763, WO 2016/205721, WO 2017/007832, WO 2017/007836, WO 2017/007840, WO 2017/087864, WO 2017/156103, WO 2017/173358, WO 2017/193046, WO 2018/009867, WO 2018/013613, WO 2018/013615, WO 2018/039378, WO 2018/064649, WO 2018/075698, WO 2018/075699, WO 2019/051264, WO 2019/051477, and WO 2019/055764; U.S. Patent Nos. 9365611, 9512165, 9630986, 9676812, 9725481, 10023606, 10172871, 10201550, and 10227375; and U.S. Patent Publication Nos. 20140057885, 20140235600, 20150018327, 20150158903, 20150175651, 20150291654, 20150315230, 20160022701, 20160031930, 20160083417, 20160083418, 20160108080, 20160152658, 20160229887, 20170152282, 20170190732, 20170232006, 20170233432, 20170233433, 20170240589, 20170246191, 20170247405, 20170247406, 20170304321, 20170305960, 20170319695, 20170342102, 20170342103, 20170348326, 20170348327, 20180037602, 20180051052, 20180141971, 20180179247, 20180194797, 20180200267, 20180201643, 20180215779, 20180237470, 20180311258, 20180311262, 20180362573, 20190008873, and 20190038639, the contents of each of which are incorporated herein by reference. The compounds described herein may contain any of the substituents described in any of the aforementioned patents and patent publications.

A "counterion" or "anionic counterion" is a negatively charged group associated with a cationic quaternary amino group in order to maintain electronic neutrality. Exemplary counterions include halide ions (e.g., F-, Cl-, Br-, l-), NO ₃ -, CIO ₄ -, OH-, HPO ₄ -, HSO ₄ -, sulfonate ions (e.g., methansulfonate, trifluoromethanesulfonate, p-toluenesulfonate, benzenesulfonate, 10- camphor sulfonate, naphthalene-2-sulfonate, naphthalene-1- sulfonic acid-5 -sulfonate, ethan-1- sulfonic acid-2-sulfonate, and the like), and carboxylate ions ( e.g., acetate, ethanoate, propanoate, benzoate, glycerate, lactate, tartrate, glycolate, and the like).

Nitrogen atoms can be substituted or unsubstituted as valency permits, and include primary, secondary, tertiary, and quaternary nitrogen atoms. Exemplary nitrogen atom

substituents include, but are not limited to, hydrogen, -OH, -OR ^aa , -N(R ^cc ) ₂ ,-CN, -C(=O)R ^aa , - C(=O)N(R ^cc )2,-CO ₂ R ^aa ,-SO ₂ R ^aa ,-C(=NR ^bb )R ^aa ,-C(=NR ^cc )OR ^aa ,-C(=NR ^cc )N(R ^cc )2,- SO ₂ N(R ^cc ) ₂ , -SO ₂ R ^cc ,-S 0 ₂ OR ^cc ,-S OR ^aa , -C(=S)N(R ^cc ) ₂ , -C(=O)SR ^cc , -C(=S)SR ^cc , - P(=O) ₂ R ^aa ,-P(=O)(R ^aa ) ₂ ,- P(=O) ₂ N(R ^cc ) ₂ , -P(=O)(NR ^cc ) ₂ , C _1-10 alkyl, C _1-10 perhaloalkyl, C _2-10 alkenyl, C _2-10 alkynyl, C _{3- 10} carbocyclyl, 3-14 membered heterocyclyl, C _6-14 aryl, and 5-14- membered heteroaryl, or two R ^cc groups attached to a nitrogen atom are joined to form a 3-14- membered heterocyclyl or 5-14- membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R ^dd groups, and wherein R ^aa , R ^bb , R ^cc and R ^dd are as defined above.

In certain embodiments, the substituent present on a nitrogen atom is an amino protecting group (also referred to herein as a nitrogen protecting group). Amino protecting groups include, but are not limited to, -OH, -OR ^aa , -N(R ^cc ) ₂ ,-C(=O)R ^aa ,-C(=O)OR ^aa ,- C(=O)N(R ^cc ) ₂ , -S(=O) ₂ R ^aa ,-

C(=NR ^cc )R ^aa ,-C(=NR ^cc )OR ^aa ,-C(=NR ^cc )N(R ^cc ) ₂ ,-SO ₂ N(R ^cc ) ₂ , - SO ₂ R ^cc , -SO ₂ OR ^cc ,-SOR ^aa ,- C(=S)N(R ^cc ) ₂ , -C(=O)SR ^CC ,-C(=S)SR ^cc , C ₁ -C ₁₀ alkyl, C _2-10 alkenyl, C _2-10 alkynyl, C _{3- 10} carbocyclyl, 3-14-membered heterocyclyl, C ₆ -C ₁₄ aryl, and 5-14- membered heteroaryl groups, wherein each alkyl, alkenyl, alkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R ^dd groups, and wherein R ^aa , R ^bb , R ^cc and R ^dd are as defined herein. Amino protecting groups are well known in the art and include those described in detail in Protecting Groups in Organic Synthesis, T. W. Greene and P. G. M. Wuts, 3rd edition, John Wiley & Sons, 1999, incorporated herein by reference.

Exemplary amino protecting groups include, but are not limited to amide groups (e.g., - C(=O)R ^aa ), which include, but are not limited to, formamide and acetamide; carbamate groups ( e.g., -C(=O)OR ^aa ), which include, but are not limited to, 9-fluorenylmethyl carbamate (Fmoc), t- butyl carbamate (BOC), and benzyl carbamate (Cbz); sulfonamide groups (e.g.,-S(=O) ₂ R ^aa ), which include, but are not limited to, p-toluenesulfonamide (Ts), methanesulfonamide (Ms), and N-[2-(trimethylsilyl)ethoxy]methylamine (SEM).

In certain embodiments, the substituent present on an oxygen atom is an oxygen protecting group (also referred to as a hydroxyl protecting group). Oxygen protecting groups include, but are not limited to, - R ^aa -N(R ^bb ) ₂ , -C(=O)SR ^aa , -C(=O)R ^aa , -CO ₂ R ^aa ,- C(=O)N(R ^bb ) ₂ , - C(=NR ^bb )R ^aa , -C(=NR ^bb )OR ^aa ,-C(=NR ^bb )N(R ^bb ) ₂ , -S(=O)R ^aa , -SO ₂ R ^aa ,- Si(R ^aa ) ₃ -P(R ^cc ) ₂ ,-P(R ^cc ) ₃ , -P(=O) ₂ R ^aa , -P(=O)(R ^aa ) ₂ ,-P(=O)(OR ^cc ) ₂ ,-P(=O) ₂ N(R ^bb ) ₂ , and - P(=O)(NR ^bb ) ₂ , wherein R ^aa , R ^bb , and R ^cc are as defined herein. Oxygen protecting groups are well known in the art and include those described in detail in Protecting Groups in Organic Synthesis, T. W. Greene and P. G. M. Wuts, 3rd edition, John Wiley & Sons, 1999, incorporated herein by reference.

Exemplary oxygen protecting groups include, but are not limited to, methyl,

methoxylmethyl (MOM), 2-methoxyethoxymethyl (MEM), benzyl (Bn), triisopropylsilyl (TIPS), t-butyldimethylsilyl (TBDMS), t-butylmethoxyphenylsilyl (TBMPS), methanesulfonate

(mesylate), and tosylate (Ts).

In certain embodiments, the substituent present on an sulfur atom is an sulfur protecting group (also referred to as a thiol protecting group). Sulfur protecting groups include, but are not limited to, - R ^aa -N(R ^bb ) ₂ , -C(=O)SR ^aa ,-C(=O)R ^aa ,-CO ₂ R ^aa ,-C(=O)N(R ^bb ) ₂ ,-C(=NR ^bb )R ^aa ,- C(=NR ^bb )OR ^aa , -C(=NR ^bb )N(R ^bb ) ₂ ,-S(=O)R ^aa , -SO ₂ R ^aa ,-Si(R ^aa ) ₃ ,-P(R ^cc ) ₂ , -P(R ^cc ) ₃ , - R(=O) ₂ R ^aa ,- P(=O)(R ^aa ) ₂ ,-P(=O)(OR ^cc ) ₂ , -P(=O) ₂ N(R ^bb ) ₂ , and -P(=O)(NR ^bb ) ₂ , wherein R ^aa , R ^bb , and R ^cc are as defined herein. Sulfur protecting groups are well known in the art and include those described in detail in Protecting Groups in Organic Synthesis, T. W. Greene and P. G. M. Wuts, 3rd edition, John Wiley & Sons, 1999, incorporated herein by reference.

As used herein, the term "modulation" refers to the inhibition or potentiation of GABA receptor function. A "modulator" (e.g., a modulator compound) may be, for example, an agonist, partial agonist, antagonist, or partial antagonist of the GABA receptor.

"Pharmaceutically acceptable" means approved or approvable by a regulatory agency of the Federal or a state government or the corresponding agency in countries other than the United States, or that is listed in the U.S. Pharmacopoeia or other generally recognized pharmacopoeia for use in animals, and more particularly, in humans.

"Pharmaceutically acceptable salt" refers to a salt of a compound of the invention that is pharmaceutically acceptable and that possesses the desired pharmacological activity of the parent compound. In particular, such salts are non-toxic may be inorganic or organic acid addition salts and base addition salts. Specifically, such salts include: (1) acid addition salts, formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like; or formed with organic acids such as acetic acid, propionic acid, hexanoic acid, cyclopentanepropionic acid, glycolic acid, pyruvic acid, lactic acid, malonic acid, succinic acid, malic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, 3-(4- hydroxybenzoyl) benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid,

ethanesulfonic acid, 1,2-ethane-disulfonic acid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid, 4-chlorobenzenesulfonic acid, 2-naphthalenesulfonic acid, 4-toluenesulfonic acid, camphorsulfonic acid, 4-methylbicyclo[2.2.2]-oct-2-ene-l-carboxylic acid, glucoheptonic acid, 3- phenylpropionic acid, trimethylacetic acid, tertiary butylacetic acid, lauryl sulfuric acid, gluconic acid, glutamic acid, hydroxynaphthoic acid, salicylic acid, stearic acid, muconic acid, and the like; or (2) salts formed when an acidic proton present in the parent compound either is replaced by a metal ion, e.g., an alkali metal ion, an alkaline earth ion, or an aluminum ion; or coordinates with an organic base such as ethanolamine, diethanolamine, triethanolamine, N methylglucamine and the like. Salts further include, by way of example only, sodium, potassium, calcium, magnesium, ammonium, tetraalkylammonium, and the like; and when the compound contains a basic functionality, salts of non-toxic organic or inorganic acids, such as hydrochloride, hydrobromide, tartrate, mesylate, acetate, maleate, oxalate and the like. The term

"pharmaceutically acceptable cation" refers to an acceptable cationic counter- ion of an acidic functional group. Such cations are exemplified by sodium, potassium, calcium, magnesium, ammonium, tetraalkylammonium cations, and the like. See, e.g., Berge, el al., J. Pharm. Sci. (1977) 66(1): 1-79.

"Solvate" refers to forms of the compound that are associated with a solvent or water (also referred to as "hydrate"), usually by a solvolysis reaction. This physical association includes hydrogen bonding. Conventional solvents include water, ethanol, acetic acid, and the like. The compounds of the invention may be prepared e.g. in crystalline form and may be solvated or hydrated. Suitable solvates include pharmaceutically acceptable solvates, such as hydrates, and further include both stoichiometric solvates and non-stoichiometric solvates. In certain instances the solvate will be capable of isolation, for example when one or more solvent molecules are incorporated in the crystal lattice of the crystalline solid. "Solvate" encompasses both solution-phase and isolable solvates. Representative solvates include hydrates, ethanolates and methanolates.

As used herein, the term "isotopic variant" refers to a compound that contains unnatural proportions of isotopes at one or more of the atoms that constitute such compound. For example, an "isotopic variant" of a compound can contain one or more non-radioactive isotopes, such as for example, deuterium ( H or D), carbon-13 ( C), nitrogen-15 ( N), or the like. It will be understood that, in a compound where such isotopic substitution is made, the following atoms, where present, may vary, so that for example, any hydrogen may be H/D, any carbon may be C, or any nitrogen may be N, and that the presence and placement of such atoms may be determined within the skill of the art. Likewise, the invention may include the preparation of isotopic variants with radioisotopes, in the instance for example, where the resulting compounds may be used for drug and/or substrate tissue distribution studies. The radioactive isotopes tritium, i.e., H, and carbon- 14, i.e., C, are particularly useful for this purpose in view of their ease of incorporation and ready means of detection. Further, compounds may be prepared that are substituted with positron emitting isotopes, such as C, F, O, and N, and would be useful in Positron Emission Topography (PET) studies for examining substrate receptor occupancy. All isotopic variants of the compounds provided herein, radioactive or not, are intended to be encompassed within the scope of the invention. "Stereoisomers" : It is also to be understood that compounds that have the same molecular formula but differ in the nature or sequence of bonding of their atoms or the arrangement of their atoms in space are termed "isomers. "Isomers that differ in the arrangement of their atoms in space are termed "stereoisomers." Stereoisomers that are not mirror images of one another are termed "diastereomers" and those that are non superimpo sable mirror images of each other are termed "enantiomers." When a compound has an asymmetric center, for example, it is bonded to four different groups, a pair of enantiomers is possible. An enantiomer can be characterized by the absolute configuration of its asymmetric center and is described by the R- and S-sequencing rules of Cahn and Prelog, or by the manner in which the molecule rotates the plane of polarized light and designated as dextrorotatory or levorotatory (i.e., as (+) or (-)- isomers respectively). A chiral compound can exist as either individual enantiomer or as a mixture thereof. A mixture containing equal proportions of the enantiomers is called a "racemic mixture".

"Tautomers" refer to compounds that are interchangeable forms of a particular compound structure, and that vary in the displacement of hydrogen atoms and electrons. Thus, two structures may be in equilibrium through the movement of n electrons and an atom (usually H). For example, enols and ketones are tautomers because they are rapidly interconverted by treatment with either acid or base. Another example of tautomerism is the aci- and nitro- forms of phenylnitromethane, that are likewise formed by treatment with acid or base. Tautomeric forms may be relevant to the attainment of the optimal chemical reactivity and biological activity of a compound of interest.

A "subject" to which administration is contemplated includes, but is not limited to, humans (i.e., a male or female of any age group, e.g., a pediatric subject (e.g, infant, child, adolescent) or adult subject (e.g., young adult, middle-aged adult or senior adult)) and/or a non human animal, e.g., a mammal such as primates (e.g., cynomolgus monkeys, rhesus monkeys), cattle, pigs, horses, sheep, goats, rodents, cats, and/or dogs. In certain embodiments, the subject is a human. In certain embodiments, the subject is a non-human animal. The terms "human," "patient," and "subject" are used interchangeably herein.

Disease, disorder, and condition are used interchangeably herein.

As used herein, and unless otherwise specified, the terms "treat," "treating" and

"treatment" contemplate an action that occurs while a subject is suffering from the specified disease, disorder or condition, which reduces the severity of the disease, disorder or condition, or retards or slows the progression of the disease, disorder or condition ("therapeutic treatment"), and also contemplates an action that occurs before a subject begins to suffer from the specified disease, disorder or condition ("prophylactic treatment").

In general, the "effective amount" of a compound refers to an amount sufficient to elicit the desired biological response, e.g., to treat a CNS-related disorder, is sufficient to induce anesthesia or sedation. As will be appreciated by those of ordinary skill in this art, the effective amount of a compound of the invention may vary depending on such factors as the desired biological endpoint, the pharmacokinetics of the compound, the disease being treated, the mode of administration, and the age, weight, health, and condition of the subject. An effective amount encompasses therapeutic and prophylactic treatment.

As used herein, and unless otherwise specified, a "therapeutically effective amount" of a compound is an amount sufficient to provide a therapeutic benefit in the treatment of a disease, disorder or condition, or to delay or minimize one or more symptoms associated with the disease, disorder or condition. A therapeutically effective amount of a compound means an amount of therapeutic agent, alone or in combination with other therapies, which provides a therapeutic benefit in the treatment of the disease, disorder or condition. The term "therapeutically effective amount" can encompass an amount that improves overall therapy, reduces or avoids symptoms or causes of disease or condition, or enhances the therapeutic efficacy of another therapeutic agent.

As used herein, and unless otherwise specified, a "prophylactically effective amount" of a compound is an amount sufficient to prevent a disease, disorder or condition, or one or more symptoms associated with the disease, disorder or condition, or prevent its recurrence. A prophylactically effective amount of a compound means an amount of a therapeutic agent, alone or in combination with other agents, which provides a prophylactic benefit in the prevention of the disease, disorder or condition. The term "prophylactically effective amount" can encompass an amount that improves overall prophylaxis or enhances the prophylactic efficacy of another prophylactic agent.

Compounds

In an aspect, the invention provides compounds of formula (I):

wherein:

A is an optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₀ , -SR ₃₁ , or -N(R ₃₁ ) ₂ ;

R _1A and R _1B are according to (i) or (ii) as follows:

(i) each of R _1A and R _1B is independently hydrogen, cyano, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted alkoxy, optionally substituted alkoxide, cyano-substituted alkyl, -SR ₃₁ , -OR ₃₁ , -SSR ₃₁ , -N(R ₃₁ ) ₂ , - NR ₃₁ N(R ₃₁ ) ₂ , -NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ ,, -S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ ,, with the proviso that R _1A and R _1B are not both hydrogen, or

(ii) R _1A and R _1B together are =O, =NR ₃₁ , or =S,

each of R ₂ and R ₃ is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ ,, or R ₂ and R ₃ together are =NR ₃₁ or =S;

R ₄ and R ₅ are according to (iii), (iv), or (v) as follows: (iii) if R4 is hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -NHC(=O)R ₃₁ , - NHC(=O)OR ₃₁ , -S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ , then R ₅ is -OR ₃₁ , -SR ₃₁ , or -N(R ₃₁ ) ₂ ,

(iv) if R4 is hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ , -NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , -S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ , then R ₅ is halogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ , or

(v) R ₄ and R ₅ together form an optionally substituted ringed structure comprising

3-6 atoms;

each of R ₆ , R ₇ , R ₈ , and R ₉ , is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ ,;

each of R ₁₀ and R ₁₁ is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ , or R ₁₀ and R ₁₁ together are =NR ₃₁ or =S;

each of R _I2 and R _I3 is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ , or R ₁₂ and R _I1 together are =NR ₃₁ or =S;

each of R14 and R15 is independently absent, hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ , or R ₁₄ and R ₁₅ together are =NR ₃₁ or =S;

each of R ₁₆ and R ₁₇ is independently absent, hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ , or R ₁₆ and R ₁₇ together are =NR ₃₁ or =S;

each of R ₁₈ and R ₁₉ is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ , or R ₁₈ and R ₁₉ together are =NR ₃₁ or =S;

R ₂₀ and R ₂₁ are according to (vi) or (vii) as follows:

(vi) if C ₁ and C ₂ form a single bond, then either:

(a) each of R ₂₀ and R ₂₁ is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ , or

(b) R ₂₀ and R ₂₁ together are =NR ₃₁ or =S; or

(vii) if C ₁ and C ₂ form a double bond, then R ₂₀ is absent and R ₂₁ is hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,- NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , -S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ ,

R ₂₂ is absent, hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , - SR31, -N(R ₃₁ )2,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , -S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ ; R ₂₃ is halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , - N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , -S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ ;

each of R ₂₄ and R ₂₅ is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ , or R ₂₄ and R ₂₅ together are =O;

each of R ₂₆ and R ₂₇ is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , -S(=O) ₂ OR ₃₁ , or R ₂₀ and R ₂₁ together are =NR ₃₁ or =S;

R ₂₈ and R ₂₉ are according to (viii), (ix), or (x) as follows:

(viii) each of R ₂₈ and R ₂₉ is independently hydrogen, halogen, cyano, nitro, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, optionally substituted heteroaryl, -OR ₃₁ , -SR ₃₁ , -N(R ₃₁ ) ₂ ,-NHC(=O)R ₃₁ , -NHC(=O)OR ₃₁ , - S(=O)R ₃₂ , -SO ₂ R ₃₂ , or -S(=O) ₂ OR ₃₁ ,

(ix) R ₂₈ and R ₂₉ together are =O, or

(x) R ₂₈ and R ₂₉ together with the carbon atom to which they are attached form a ring;

each instance of R ₃₀ is independently hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, carbocyclyl, heterocyclyl, aryl, or heteroaryl; each instance of R ₃₁ is independently hydrogen, hydroxy, alkyl, alkenyl, alkynyl, alkoxy, carbocyclyl, heterocyclyl, aryl, heteroaryl, amine, nitrate, nitrite, thiol, thioether, thioester, sulfate, sulfite, disulfide, sulfoxide, phosphate, phosphate ester, thiophosphate, thiophosphate ester, phosphonate, phosphonate ester, thiophosphonate, thiophosphonate ester, an oxygen protecting group when attached to an oxygen atom, a sulfur protecting group when attached to a sulfur atom, a nitrogen protecting group when attached to a nitrogen atom, or two R ₃₁ groups are joined to form an heterocyclic or heteroaryl ring;

each instance of R ₃₂ is independently hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, or optionally substituted heteroaryl; and each instance of R ₃₃ is independently hydrogen, an optionally substituted C _1-6 alkyl, optionally substituted C _2-6 alkenyl, optionally substituted C _2-6 alkynyl, or optionally substituted C _3-6 carbocyclyl;

wherein:

(xi) if C ₁ and C ₂ form a single bond, R _1A and R _1B together are =O, and R ₄ and R ₅ do not form a ringed structure, then at least one of the following conditions is satisfied:

(a) at least one of R ₂ , R ₃ , R ₆ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , or R ₂₂ is not H;

(b) neither of R ₁₂ and R ₁₃ is H;

(c) neither of R ₁₄ and R ₁₅ is H;

(d) neither of R ₁₆ and R ₁₇ is H;

(e) neither of R ₁₈ and R ₁₉ is H;

(f) neither of R ₂₀ and R ₂₁ is H; and

(g) neither of R ₂₆ and R ₂₇ is H;

(xii) if C ₁ and C ₂ form a single bond and either of R _1A and R _1B is optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkoxy, or hydroxyl, and R ₄ and R ₅ do not form a ringed structure, then at least one of the following conditions is satisfied:

(a) at least one of R ₂ , R ₃ , R ₆ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , R ₂₀ , R ₂₁ , or R ₂₂ is not H;

(b) neither of R ₁₂ and R ₁₃ is H;

(c) neither of R ₁₆ and R ₁₇ is H;

(d) neither of R ₁₈ and R ₁₉ is H; and

(e) neither of R ₂₆ and R ₂₇ is H;

(xiii) if C ₁ and C ₂ form a single bond, R _1A and R _1B together are =O, both R ₁₆ and R ₁₇ are present, and neither of R ₁₆ and R ₁₇ is H, then R ₂₃ is alkyl; and

(xiv) if C ₁ and C ₂ form a single bond and either of R _1A and R _1B is alkyl, then:

(a) R ₂₈ , and R ₂₉ , are not -OH; and

(b) A is not substituted with -OH; and (xv) if C ₁ and C ₂ form a single bond, R _1A and R _1B together are =S or =NR ₃₁ , and R ₄ and R ₅ do not form a ringed structure, then at least one of the following conditions is satisfied:

(a) at least one of R ₂ , R ₃ , R ₁₀ , R ₁₁ , R ₁₄ , R ₁₅ , R ₁₈ , R ₁₉ , R ₂₀ , R ₂₁ , R ₂₆ and R ₂₇ is not H;

(b) neither of R ₁₂ and R ₁₃ is H; and

(c) neither of R ₂₄ and R ₂₅ is H.

In certain embodiments, R _1A and R _1B together are =NH or =S. In certain embodiments,

R _1A and R _1B together are =CH ₂ .

In certain embodiments and at least one of R ₂₀ and R ₂₁ is not H.

In certain embodiments, R ₂₃ is an optionally substituted alkyl. In certain embodiments,

R ₂₃ is a C ₁ -C ₆ alkyl. In certain embodiments, R ₂₃ is methyl.

In certain embodiments, R ₇ is an optionally substituted alkyl. In certain embodiments, R ₇ is a C ₁ -C ₆ alkyl. In certain embodiments, R ₇ is methyl.

In certain embodiments, A is an optionally substituted heteroaryl. In certain

embodiments, A is an optionally substituted pyrazole. In certain embodiments, A is represented by the following structure:

In certain embodiments, at least one of R ₂₀ and R ₂₁ is not hydrogen.

In certain embodiments, the compound of formula (I) has a structure represented by one of formulas (la), (lb), (Ic), (Id), (Ie), (If), (Ig), (Ih), and (Ii):

In certain embodiments, the compound of formula (I) has a structure represented by one of formulas (la-1), (Ib-1), (Ic-1), (Id-1), (Ie-1), (If-1), (Ig-1), (Ih-1), and (Ii-1):

Other compounds of the invention are represented by the following structures:

Compounds of the invention may be classified based on structural features. In certain embodiments, the compounds are classified based on the nature of the bond(s) on the carbon atom that corresponds to carbon 20 in the following numbering scheme for the steroid core:

In certain embodiments, the compounds are members of a ketone series. Compounds in the ketone series may have one of the following structures:

In certain embodiments, the compounds are members of a thio series. Compounds in the thio series may have one of the following structures:

In certain embodiments, the compounds are members of an imine series. Compounds in the imine series may have one of the following structures:

In certain embodiments, the compounds are members of a alkene series. Compounds in the alkene series may have one of the following structures:

In certain embodiments, the compounds are members of a methyl-hydroxy series. Compounds in the methyl-hydroxy series may have one of the following structures:

In certain embodiments, the compounds are members of a hydrazine series. Compounds in the hydrazine series may have one of the following structures:

The invention includes all isotopic variants of the compounds described herein. For example and without limitation, any of the carbon, hydrogen, nitrogen, or oxygen atoms in the compounds may enriched for any of the isotopes described above.

Formulations

The invention provides pharmaceutical compositions containing one or more of the compounds described above. A pharmaceutical composition containing the compounds may be in a form suitable for oral use, for example, as tablets, troches, lozenges, fast-melts, aqueous or oily suspensions, dispersible powders or granules, emulsions, hard or soft capsules, syrups or elixirs. Compositions intended for oral use may be prepared according to any method known in the art for the manufacture of pharmaceutical compositions and such compositions may contain one or more agents selected from sweetening agents, flavoring agents, coloring agents and preserving agents, in order to provide pharmaceutically elegant and palatable preparations.

Tablets contain the compounds in admixture with non-toxic pharmaceutically acceptable excipients which are suitable for the manufacture of tablets. These excipients may be for example, inert diluents, such as calcium carbonate, sodium carbonate, lactose, calcium phosphate or sodium phosphate; granulating and disintegrating agents, for example corn starch, or alginic acid; binding agents, for example starch, gelatin or acacia, and lubricating agents, for example magnesium stearate, stearic acid or talc. The tablets may be uncoated or they may be coated by known techniques to delay disintegration in the stomach and absorption lower down in the gastrointestinal tract and thereby provide a sustained action over a longer period. For example, a time delay material such as glyceryl monostearate or glyceryl distearate may be employed. They may also be coated by the techniques described in U.S. Patent Nos. 4,256,108; 4,166,452; and 4,265,874, the contents of which are incorporated herein by reference, to form osmotic therapeutic tablets for control release. Preparation and administration of compounds is discussed in U.S. Patent No. 6,214,841 and U.S. Pub. No. 2003/0232877, the contents of which are incorporated herein by reference.

Formulations for oral use may also be presented as hard gelatin capsules in which the compounds are mixed with an inert solid diluent, for example calcium carbonate, calcium phosphate or kaolin, or as soft gelatin capsules in which the compounds are mixed with water or an oil medium, for example peanut oil, liquid paraffin or olive oil.

An alternative oral formulation, where control of gastrointestinal tract hydrolysis of the compound is sought, can be achieved using a controlled-release formulation, where a compound of the invention is encapsulated in an enteric coating.

Aqueous suspensions may contain the compounds in admixture with excipients suitable for the manufacture of aqueous suspensions. Such excipients are suspending agents, for example sodium carboxymethylcellulose, methylcellulose, hydroxypropylmethylcellulose, sodium alginate, polyvinylpyrrolidone, gum tragacanth and gum acacia; dispersing or wetting agents such as a naturally occurring phosphatide, for example lecithin, or condensation products of an alkylene oxide with fatty acids, for example, polyoxyethylene stearate, or condensation products of ethylene oxide with long chain aliphatic alcohols, for example heptadecaethyleneoxycetanol, or condensation products of ethylene oxide with partial esters derived from fatty acids and a hexitol such a polyoxyethylene with partial esters derived from fatty acids and hexitol anhydrides, for example polyoxyethylene sorbitan monooleate. The aqueous suspensions may also contain one or more preservatives, for example ethyl, or n-propyl p-hydroxybenzoate, one or more coloring agents, one or more flavoring agents, and one or more sweetening agents, such as sucrose or saccharin.

Oily suspensions may be formulated by suspending the compounds in a vegetable oil, for example, arachis oil, olive oil, sesame oil or coconut oil, or in a mineral oil such as liquid paraffin. The oily suspensions may contain a thickening agent, for example beeswax, hard paraffin or cetyl alcohol. Sweetening agents such as those set forth above, and flavoring agents may be added to provide a palatable oral preparation. These compositions may be preserved by the addition of an anti-oxidant such as ascorbic acid.

Dispersible powders and granules suitable for preparation of an aqueous suspension by the addition of water provide the compounds in admixture with a dispersing or wetting agent, suspending agent and one or more preservatives. Suitable dispersing or wetting agents and suspending agents are exemplified, for example sweetening, flavoring and coloring agents, may also be present.

The pharmaceutical compositions of the invention may also be in the form of oil-in-water emulsions. The oily phase may be a vegetable oil, for example olive oil or arachis oil, or a mineral oil, for example liquid paraffin or mixtures of these. Suitable emulsifying agents may be naturally-occurring gums, for example gum acacia or gum tragacanth, naturally occurring phosphatides, for example soya bean, lecithin, and esters or partial esters derived from fatty acids and hexitol anhydrides, for example sorbitan monooleate and condensation products of the said partial esters with ethylene oxide, for example polyoxyethylene sorbitan monooleate. The emulsions may also contain sweetening and flavoring agents.

Syrups and elixirs may be formulated with sweetening agents, such as glycerol, propylene glycol, sorbitol or sucrose. Such formulations may also contain a demulcent, a preservative, and agents for flavoring and/or coloring. The pharmaceutical compositions may be in the form of a sterile injectable aqueous or oleaginous suspension. This suspension may be formulated according to the known art using those suitable dispersing or wetting agents and suspending agents which have been mentioned above. The sterile injectable preparation may also be in a sterile injectable solution or suspension in a non-toxic parenterally acceptable diluent or solvent, for example as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose any bland fixed oil may be employed including synthetic mono- or di-glycerides. In addition, fatty acids such as oleic acid find use in the preparation of injectables.

In certain embodiments, the formulation is not a sustained release formulation. In certain embodiments, the the formulation is not injectable. In certain embodiments, the formulation does not contain particles having a D50 (volume weighted median diameter) of less than 10 microns. In certain embodiments, the formulation does not contain a polymer surface stabilizer. In certain embodiments, the formulation is not an aqueous suspension. Treatment of CNS disorders

The compositions of the invention are useful for treating CNS disorders that are associated with, or can be ameliorated by, alteration of activity of a GABA _A receptor. GABA _A receptors are responsible for most of the physiological activities of GABA in the central nervous system. GABA _A receptors are generally pentamers that include various combinations of a, b, and γ subunits, but the minimal requirement to produce a GABA-gated ion channel is the inclusion of an a and a β subunit. GABA _A receptors may include other subunits as well, and the arrangement of subunits within the pentamer can vary. Moreover, there are multiple members of each subunit family, making a vast number of potential combinations to yield functional receptors. Within neurons, the type and density of GABA _A receptors can vary between cell bodies and dendrites. The structure and function of GABA _A receptors are described in, for example, Sigel E., and Steinmann, M.E., Structure, Function, and Modulation of GABA _A Receptors, J. Biol. Chem. 287:48 pp. 40224-402311 (2012), doi: 10.1074/jbc.Rl 12.386664, the contents of which are incorporated herein by reference.

Modulation of GABA _A receptor activity is useful for treatment of a variety of CNS diseases, disorders, and condition. For example and without limitation, the CNS-related disease, disorder, or condition may be an addictive disorder, Alzheimer’s disease, an epileptic disorder, Angelman's syndrome, an anxiety disorder, an attention disorder, an auditory disorder, an Autism spectrum disorder, bipolar disorder, a cognitive disorder, a compulsive disorder, a convulsive disorder, dementia, depression, dysthymia, essential tremor, fragile X syndrome, Huntington’s disease, insomnia, a memory disorder, migraines a mood disorder, a

neurodegenerative disease, an obsessive compulsive disorder, pain, a panic disorder, Parkinson’s disease, a personality disorder, posttraumatic stress disorder, psychosis, Rett syndrome, a schizoaffective disorder, schizophrenia, a seizure disorder, a sleep disorder, social anxiety disorder, stroke, tinnitus, traumatic brain injury, Wilson's disease, or withdrawal syndrome.

The methods of treating a subject having a CNS disease, disorder, or condition include providing a composition of the invention, as described above, to the subject. Providing may include administering the composition to the subject. The composition may be administered by any suitable means, such as orally, intravenously, enterally, parenterally, dermally, buccally, topically (including transdermally), by injection, nasally, pulmonarily, and with or on an implantable medical device (e.g., stent or drug-eluting stent or balloon equivalents). Preferably, the composition is provided orally.

The composition may be provided under any suitable dosing regimen. For example, the composition may be provided as a single dose or in multiple doses. Multiple doses may be provided in provided separated by intervals, such as 4 hours, 6 hours, 8 hours, 12 hours, 24 hours, 2 days, 3 days, 4 days, 5 days, 1 week, 2 weeks, 3 weeks, 4 weeks, or more. Multiple doses may be provided within a period of time. For example, multiple doses may be provided over a period of 1 day, 2 days, 3 days, 4 days, 5 days, 1 week, 2 weeks, 3 weeks, 4 weeks, or more. The compositions may be provided repeatedly for a specified duration. For example and without limitation, the compositions may be provided for 1 week, 2 weeks, 3 weeks, 4 weeks, 6 weeks, 8 weeks, 12 weeks, 3 months, 4 months, 5 months, 6 months, 8 months, 10 months, 12 months or more.

Incorporation by Reference

References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes.

Equivalents

Various modifications of the invention and many further embodiments thereof, in addition to those shown and described herein, will become apparent to those skilled in the art from the full contents of this document, including references to the scientific and patent literature cited herein. The subject matter herein contains important information, exemplification, and guidance that can be adapted to the practice of this invention in its various embodiments and equivalents thereof.