Amides useful as inhibitors of voltage-gated sodium channels

1. A method of inhibiting a sodium channel comprising the step of contacting said channel with a compound of formula I:

or a pharmaceutically acceptable salt thereof, wherein:

X is O;

radical

is selected from

Ring A is phenyl or

wherein ring A is optionally substituted with up to y occurrences of R 5 ;

R A is selected from SO 2 N(R 2 ) 2 , SO 2 R 1 ;

R 1 is C 1-6 aliphatic, wherein up to two carbon atoms other than the atom attached to the nitrogen or oxygen atom is optionally replaced with O, S, NR N , or C(O);

each R 2 is independently hydrogen, or C 1-6 aliphatic, wherein up to two carbon atoms other than the atom attached to the nitrogen or oxygen atom is optionally replaced with O, S, NR N , or C(O);

x is 0-4;

y is 0-4;

each occurrence of R N is independently selected from hydrogen or a C 1-6 aliphatic group optionally substituted with 1-3 independent occurrences of —R J , oxo, thioxo, —CO 2 R J , —OR J , —N(R J ) 2 , —SR J , —NO 2 , halogen, —CN, —C 1-4 haloalkyl, —C 1-4 -haloalkoxy, —C(O)N(R J ) 2 , —NR J C(O)R J , —SO 2 R J , —SO 2 N(R J ) 2 , —NR J SO 2 R J , —NR J CON(R J ) 2 , —NR J CO 2 R J , —COR J , —OCOR J , —OCON(R J ) 2 , —SOR J , —NR J SO 2 N(R J ) 2 , —COCOR J , —COCH 2 COR J , —OP(O)(R J ) 2 , —P(O)(OR J ) 2 , —PO(OR J )(R J ), —P(O)(R J ) 2 , or —OP(O)(OR J ) 2 ; wherein

R J is hydrogen or unsubstituted C 1-6 aliphatic;

each occurrence of R 3 , R 4 , and R 5 is independently Q-R X ;

Q is a bond or is a C 1-6 aliphatic chain wherein up to three methylene units of Q are optionally and independently replaced by —NH—, —NR—, —O—, —S—, —CO 2 —, —OC(O)—, —C(O)CO—, —C(O)—, —C(S)—, —C(O)NH—, —C(O)NR—, —C(═N—CN)—, —NHCO—, —NRCO—, —NHC(O)O—, —NRC(O)O—, —SO 2 NH—, —SO 2 NR—, —NHSO 2 —, —NRSO 2 —, —NHC(O)NH—, —NRC(O)NH—, —NHC(O)NR—, —NRC(O)NR, —OC(O)NH—, —OC(O)NR—, —NHSO 2 NH—, —NRSO 2 NH—, —NHSO 2 NR—, —NRSO 2 NR—, —SO— or —SO 2 —; wherein

Q is optionally substituted with 1-3 independent occurrences of R Q ;

each occurrence of R X is independently selected from —R′, halogen, —NO 2 , —CN, —OR′, —SR′, —N(R′) 2 , —NR′C(O)R′, —NR′C(O)N(R′) 2 , —NR′CO 2 R′, —C(O)R′, —CO 2 R′, —OC(O)R′, —C(O)N(R′) 2 , —OC(O)N(R′) 2 , —SOR′, —SO 2 R′, —SO 2 N(R′) 2 , —NR′SO 2 R′, —NR′SO 2 N(R′) 2 , —C(O)C(O)R′, —C(O)CH 2 C(O)R′, —OP(O)(OR′) 2 , —P(O)(OR′) 2 , —PO(OR′)(R′), —P(O)(R′) 2 , or —OP(O)(R′) 2 ;

each occurrence of R is independently selected from hydrogen or a C 1-6 aliphatic group optionally substituted with 1-3 independent occurrences of —R T , -T-Ar 1 , halogen, oxo, thioxo, —OR T , —SR T , —N(R T ) 2 , —NO 2 , —C 1-4 haloalkyl, —C 1-4 haloalkoxy, —CN, —CO 2 R T , —COR T , —CON(R T ) 2 , —OCOR T , —NR T COR T , —SO 2 R T , —SO 2 N(R T ) 2 , or —NR T SO 2 R T ; wherein

each R T is independently hydrogen or unsubstituted C 1-6 aliphatic; or

any two R T groups, on the same substituent or different substituents, together with the atom(s) to which each group is bound, optionally form a 3-8 membered saturated or partially unsaturated monocyclic ring, or a 5-6 membered monocyclic aryl ring having 0-3 heteroatoms independently selected from nitrogen, oxygen, or sulfur; wherein said monocyclic ring is optionally substituted with 1-3 independent occurrences of —R R , -T-Ar 1 , halogen, oxo, thioxo, —OR R , —SR R , —N(R R ) 2 , —NO 2 , —C 1-4 haloalkyl, —C 1-4 haloalkoxy, —CN, —CO 2 R R , —COR R , —CON(R R ) 2 , —OCOR R , —NR R COR R , —SO 2 R R , —SO 2 N(R R ) 2 , or —NR R SO 2 R R ; wherein

each R R is independently hydrogen or unsubstituted C 1-6 aliphatic;

T is (CH 2 ) w ;

w is 0-2;

Ar 1 is selected from a 3-8 membered saturated or partially unsaturated ring, a 5-6 membered aryl ring, a 3-7 membered heterocyclic ring having 1-3 heteroatoms independently selected from nitrogen, oxygen, or sulfur, a 5-6 membered heteroaryl ring having 1-3 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an 8-12 membered saturated, partially unsaturated, or fully unsaturated bicyclic ring system having 0-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur; wherein

Ar 1 is optionally substituted with 1-3 independent occurrences of —R W , oxo, thioxo, —CO 2 R W , —OR W , —N(R W ) 2 , —SR W , —NO 2 , halogen, —CN, —C 1-4 haloalkyl, —C 1-4 haloalkoxy, —C(O)N(R W ) 2 , —NR W C(O)R W , —SO 2 R W , —SO 2 N(R W ) 2 , —NR W SO 2 R W , —NR W CON(R W ) 2 , —NR W CO 2 R W , —COR W , —OCOR W , —OCON(R W ) 2 , —SOR W , —NR W SO 2 N(R W ) 2 , —COCOR W , —COCH 2 COR W , —OP(O)(OR W ) 2 , —P(O)(OR W ) 2 , —PO(OR W )(R W ), —P(O)(R W ) 2 , or —OP(O)(R W ) 2 ; wherein

R W is hydrogen or unsubstituted C 1-6 aliphatic;

R Q is selected from halogen, —R S , —N(R S ) 2 , —SR S , —OR S , C 3-10 cycloaliphatic, C 6-10 aryl, 5-10 membered heteroaryl, 5-10 membered heterocyclyl, oxo, thioxo, —C 1-4 haloalkoxy, —C 1-4 haloalkyl, —NO 2 , —CN, —CF 3 , —OCF 3 , —CO 2 R S , —COR S , —OC(O)R S or —NR S C(O)R S ; wherein

R S is hydrogen or unsubstituted C 1-6 aliphatic; or

any two R Q or two R S groups, or any combination of an R Q group with an R S group on the same substituent or different substituents, together with the atom(s) to which each group is bound, optionally form a 3-8 membered saturated or partially unsaturated monocyclic ring, or a 5-6 membered monocyclic aryl ring; each ring having 0-3 heteroatoms independently selected from nitrogen, oxygen, or sulfur; wherein any of said monocyclic ring is optionally substituted with 1-3 independent occurrences of R O , halogen, oxo, thioxo, —OR O , —SR O , —N(R O ) 2 , —NO 2 , —C 1-4 haloalkyl, —C 1-4 haloalkoxy, —CN, —CO 2 R O , —COR O , —CON(R O ) 2 , —OCOR O , —NR O COR O , —SO 2 R O , —SO 2 N(R O ) 2 , or —NR O SO 2 R O ; wherein

R O is hydrogen or unsubstituted C 1-6 aliphatic; and

each occurrence of R′ is independently selected from hydrogen or a C 1-8 aliphatic, C 6-10 aryl, a heteroaryl ring having 5-10 ring atoms, or a heterocyclyl ring having 3-10 ring atoms, or wherein R and R′ taken together with the atom(s) to which they are bound, or two occurrences of R′ taken together with the atom(s) to which they are bound, form a 5-8 membered cycloalkyl, heterocyclyl, aryl, or heteroaryl ring having 0-3 heteroatoms independently selected from nitrogen, oxygen, or sulfur; wherein said C 1-8 aliphatic, C 6-10 aryl, heteroaryl ring or heterocyclyl ring is optionally substituted with 1-3 independent occurrences of R I , halogen, oxo, thioxo, —OR I , —SR I , —N(R I ) 2 , —NO 2 , —C 1-4 -haloalkyl, —C 1-4 -haloalkoxy, —CN, —CO 2 R I , —COR I , —CONHR I , —OCOR I , —NR I COR I , —SO 2 R I , —SO 2 N(R I ) 2 , or —NR I SO 2 R I ; wherein

R I is hydrogen or unsubstituted C 1-6 aliphatic.

2. The method according to claim 1 , wherein x is 0-2.

3. The method according to claim 1 , wherein x is 2.

4. The method according to claim 1 , wherein x is 1.

5. The method according to claim 1 , wherein x is 1-3, and each R 3 is independently selected from hydrogen, halogen, CN, CF 3 , NO 2 , or an optionally substituted group selected from C 1-6 aliphatic, C 1-6 cycloaliphatic, C 6-10 aryl, 5-6 membered heteroaryl, 4-7 membered heterocyclyl, aralkyl, —N(R′) 2 , —CH 2 N(R′) 2 , —OR′, —CH 2 OR′, —SR′, —CH 2 SR′, —C(O)R′, —COOR′, —NRCOR′, —CON(R′) 2 , —S(O) 2 R′, or —S(O) 2 N(R′) 2 .

6. The method according to claim 5 , wherein x is 1-3, and each R 3 is independently selected from Cl, Br, F, CF 3 , methyl, ethyl, propyl, isopropyl, t-butyl, isobutyl, sec-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, CN, NO 2 , —COOH, —N(CH 3 ) 2 , —N(Et) 2 , —N(iPr) 2 , —O(CH 2 ) 2 OCH 3 , —CONH 2 , —COO(C 1-6 alkyl), —OH, —OCF 3 , —SCF 3 , —OCH 3 , —CH 2 OH, —NHCOCH 3 , —SO 2 NH 2 , —SO 2 CH 3 , methylenedioxy, ethylenedioxy, or an optionally substituted group selected from pyrrolyl, thiadiazolyl, pyridyl, imidazolyl, pyrazolyl, piperidinyl, piperazinyl, morpholinyl, 2-oxo-imidazolidyl, C 1-4 alkoxy, phenyl, phenylethyl, phenyloxy, phenyloxymethyl, phenylformyl, benzyl, benzylamino, or benzyloxy.

7. The method according to claim 1 , wherein y is 1-3, and each R 5 is independently selected from hydrogen, halogen, CN, NO 2 , or an optionally substituted group selected from C 1-4 aliphatic, aryl, 5-6 membered heteroaryl, 4-7 membered heterocyclyl, aralkyl, —N(R′) 2 , —CH 2 N(R′) 2 , —OR′, —CH 2 OR′, —SR′, —CH 2 SR′, —COOR′, —NRCOR′, —CON(R′) 2 , or —S(O) 2 N(R′) 2 .

8. The method according to claim 7 , wherein y is 1-3, and each R 5 is independently selected from Cl, Br, F, CF 3 , methyl, ethyl, CN, —COOH, —N(CH 3 ) 2 , —N(Et) 2 , —N(iPr) 2 , —O(CH 2 ) 2 OCH 3 , —CONH 2 , —COOCH 3 , —OH, —CH 2 OH, —NHCOCH 3 , —SO 2 NH 2 , methylenedioxy, ethylenedioxy, piperidinyl, piperazinyl, morpholino, or an optionally substituted group selected from C 1-4 -alkoxy, phenyl, phenyloxy, benzyl, or benzyloxy.

9. The method according to claim 1 , wherein each R 4 is hydrogen.

10. The method according to claim 1 , wherein each R 4 , when present, is independently selected from hydrogen, halogen, CN, NO 2 , or an optionally substituted group selected from C 1-6 aliphatic, aryl, 5-6 membered heteroaryl, 4-7 membered heterocyclyl, aralkyl, —N(R′) 2 , —CH 2 N(R′) 2 , —OR′, —CH 2 OR′, —SR′, —CH 2 SR′, —C(O)R′, —COOR′, —NR′COR′, —CON(R′) 2 , or —S(O) 2 N(R′) 2 .

11. The method according to claim 1 , wherein R A is SO 2 N(R 2 ) 2 and both R 2 are hydrogen.

12. The method according to claim 1 , wherein R A is SO 2 R 1 and R 1 is C 1-6 alkyl.

13. The method according to claim 1 , wherein ring A is optionally substituted phenyl.

14. A method of treating or lessening the severity in a subject of acute pain, chronic pain, neuropathic pain, inflammatory pain, radicular pain, sciatica, back pain, head pain, neck pain, intractable pain, tinnitus or cancer pain, comprising administering an effective amount of a compound according to claim 1 or a pharmaceutically acceptable composition comprising a compound to said subject in need thereof.