11,13-modified saxitoxins for the treatment of pain
Provided herein are compounds, pharmaceutical compositions comprising the compounds, methods of preparing the compounds, and methods of using the compounds and compositions in treating conditions associated with voltage-gated sodium channel function where the compounds are 11,13-modified saxitoxins according to Formula (I): where R 4 , R 4a , R 7 , R 7a , and X 2 are as described herein.
1. A Compound of Formula (I):
wherein
X 2 is —N(R 8 )—;
R 4 and R 4a are independently hydrogen or C 1-6 alkyl;
R 7 is hydrogen or C 1-6 alkyl;
R 7a is aryl optionally substituted with 1, 2, 3, or 4 R 7b ; heterocyclic optionally substituted with 1, 2, 3, or 4 R 7b ; or biphenyl optionally substituted with 1, 2, 3, or 4 R 7b ;
each R 7b , when present, is independently halo, C 1-6 alkyl, halo-C 1-6 alkyl, aryl-C 1-6 alkyl, hydroxy, C 1-6 alkoxy, halo-C 1-6 alkoxy, aryloxy, nitro, C 1-6 alkylthio, halo-C 1-6 alkylthio, C 1-6 alkylsulfinyl, halo-C 1-6 alkylsulfinyl, C 1-6 alkylsulfonyl, halo-C 1-6 alkylsulfonyl, amino, C 1-6 alkylamino, di-C 1-6 alkylamino, —C(O)(heterocycloalkyl), or cyano; where the aryl in aryloxy and aryl-C 1-6 alkyl are optionally substituted with 1, 2, or 3 groups independently selected from C 1-6 alkyl, halo, and halo-C 1-6 alkyl; and
R 8 is C 3 -C 8 -cycloalkyl; or
as a pharmaceutically acceptable salt or salts thereof; or a hydrate, solvate, stereoisomer, tautomer, or mixture thereof.
2. The Compound of claim 1 , where the compound is according to Formula (Ib):
as a pharmaceutically acceptable salt or salts thereof; or a hydrate, solvate, stereoisomer, tautomer, or mixture thereof.
3. The Compound of claim 1 , where R 4 and R 4a are each hydrogen; as a pharmaceutically acceptable salt or salts thereof; or a hydrate, solvate, stereoisomer, tautomer, or mixture thereof.
4. The Compound of claim 1 , where R 7 is hydrogen; as a pharmaceutically acceptable salt or salts thereof; or a hydrate, solvate, stereoisomer, tautomer, or mixture thereof.
5. The Compound of claim 1 , where the aryl in R 7a is phenyl, naphthyl, tetrahydronaphthyl, fluorenyl, 6,7,8,9-tetrahydro-5H-benzo[7]annulenyl,
or indanyl; each of which is optionally substituted with 1, 2, or 3 groups independently selected from halo, C 1-6 alkyl, halo-C 1-6 alkyl, hydroxy, C 1-6 alkoxy, halo-C 1-6 alkoxy, C 1-6 alkylthio, C 1-6 alkylsulfonyl, and amino; as a pharmaceutically acceptable salt or salts thereof; or a hydrate, solvate, stereoisomer, tautomer, or mixture thereof.
6. The Compound of claim 1 , where the heterocyclic in R 7a is benzo-1,4-dioxanyl, benzodioxolyl, 2,3-dihydrobenzofuranyl, chromanyl,
or 2,2-dioxo-1,3-dihydrobenzo[c]thienyl; each of which is optionally substituted with 1, 2, or 3 groups independently selected from halo, C 1-6 alkyl, halo-C 1-6 alkyl, hydroxy, C 1-6 alkoxy, halo-C 1-6 alkoxy, and phenyl; as a pharmaceutically acceptable salt or salt thereof; or a hydrate, solvate, stereoisomer, tautomer, or mixture thereof.
7. The Compound of claim 1 , where R 7a is
where X 3 is —O—, —O—C(R 7b3 )(R 7b3 )—, —C(R 7b3 )(R 7b3 )—O—, —C(R 7b3 )(R 7b3 )—, —C(R 7b3 )(R 7b3 )—C(R 7b4 )(R 7b4 )—, or —C(R 7b3 )(R 7b3 )—C(R 7b4 )(R 7b4 )—C(R 7b5 )(R 7b5 )— and each R 7b1 , R 7b2 , R 7b3 , R 7b4 , and R 7b5 is independently hydrogen, halo, or C 1-3 -alkyl; as a pharmaceutically acceptable salt or salts thereof; or a hydrate, solvate, stereoisomer, tautomer, or mixture thereof.
8. The Compound of claim 7 , where a) one R 7b1 is methyl or ethyl and the other R 7b1 is hydrogen, or b) the two R 7b1 are both hydrogen, or c) the two R 7b1 are both methyl; and each R 7b2 , R 7b3 , R 7b4 , and R 7b5 are hydrogen; as a pharmaceutically acceptable salt or salts thereof; or a hydrate, solvate, stereoisomer, tautomer, or mixture thereof.
9. The Compound of claim 1 , where R 7a is
as a pharmaceutically acceptable salt or salts thereof; or a hydrate, solvate, stereoisomer, tautomer, or mixture thereof.
10. The Compound of claim 9 , where R 7a is
as a pharmaceutically acceptable salt or salts thereof; or a hydrate, solvate, stereoisomer, tautomer, or mixture thereof.
11. The Compound of claim 1 , selected from
as a pharmaceutically acceptable salt or salts thereof; or a hydrate, solvate, stereoisomer, tautomer, or mixture thereof.
12. A pharmaceutical composition comprising the compound of claim 1 , as a pharmaceutically acceptable salt or salts thereof; or a hydrate, solvate, stereoisomer, tautomer, or mixture thereof; and a pharmaceutically acceptable excipient, carrier or diluent.
13. A method for the treatment of a condition associated with voltage-gated sodium channel function in a mammal, comprising the administration of a therapeutically or prophylactically effective amount of a pharmaceutical composition of claim 12 , wherein the condition is pain, cough, itch, or discomfort associated with dry eye syndrome.
14. The method of claim 13 , wherein the mammal is a human.
15. The method of claim 14 , where the condition is pain.
16. The method of claim 15 , where the condition is pain selected from pain associated with erythromelalgia, pain associated with diabetic peripheral neuropathy, paroxysmal extreme pain disorder, complex regional pain syndrome, pain associated with trigeminal neuralgia, pain associated with multiple sclerosis, pain associated with arthritis, pain associated with osteoarthritis, pain associated with postherpetic neuralgia, cancer pain, pain associated with cluster headache, pain associated with migraine, pain associated with sciatica, pain associated with endometriosis, pain associated with fibromyalgia, postsurgical pain, subacute pain, chronic pain, pain associated with dry eye syndrome, pain associated with (acute) corneal injuries or abrasions, acute ocular pain, chronic ocular pain, pain associated with corneal infections, pain associated with Parkinson's disease, pain associated with ALS, and pain associated with ocular surgery.
17. The method of claim 13 , where the condition is selected from acute pain, subacute pain, and postsurgical pain.
18. A compound of Formula Xe
or salt(s) thereof, where
PG 1 is a nitrogen-protecting group;
PG 2 is a nitrogen-protecting group;
X 2 is —N(R 8 )—;
R 4 and R 4a are independently hydrogen or C 1-6 alkyl;
R 7 is hydrogen or C 1-6 alkyl;
R 7a is aryl optionally substituted with 1, 2, 3, or 4 R 7b ; heterocyclic optionally substituted with 1, 2, 3, or 4 R 7b ; or biphenyl optionally substituted with 1, 2, 3, or 4 R 7b ;
each R 7b , when present, is independently halo, C 1-6 alkyl, halo-C 1-6 alkyl, aryl-C 1-6 alkyl, hydroxy, C 1-6 alkoxy, halo-C 1-6 alkoxy, aryloxy, nitro, C 1-6 alkylthio, halo-C 1-6 alkylthio, C 1-6 alkylsulfinyl, halo-C 1-6 alkylsulfinyl, C 1-6 alkylsulfonyl, halo-C 1-6 alkylsulfonyl, amino, C 1-6 alkylamino, di-C 1-6 alkylamino, —C(O)(heterocycloalkyl), or cyano; where the aryl in aryloxy and aryl-C 1-6 alkyl are optionally substituted with 1, 2, or 3 groups independently selected from C 1-6 alkyl, halo, and halo-C 1-6 alkyl; and
R 8 is C 3 -C 8 -cycloalkyl.
19. A method of preparing a compound of Formula (I) comprising
a) deprotecting a compound of Formula Xe
or salt thereof, where
PG 1 is a nitrogen-protecting group;
PG 2 is a nitrogen-protecting group;
X 2 is —N(R 8 )—;
R 4 and R 4a are independently hydrogen or C 1-6 alkyl;
R 7 is hydrogen or C 1-6 alkyl;
R 7a is aryl optionally substituted with 1, 2, 3, or 4 R 7b ; heterocyclic optionally substituted with 1, 2, 3, or 4 R 7b ; or biphenyl optionally substituted with 1, 2, 3, or 4 R 7b ;
each R 7b , when present, is independently halo, C 1-6 alkyl, halo-C 1-6 alkyl, aryl-C 1-6 alkyl, hydroxy, C 1-6 alkoxy, halo-C 1-6 alkoxy, aryloxy, nitro, C 1-6 alkylthio, halo-C 1-6 alkylthio, C 1-6 alkylsulfinyl, halo-C 1-6 alkylsulfinyl, C 1-6 alkylsulfonyl, halo-C 1-6 alkylsulfonyl, amino, C 1-6 alkylamino, di-C 1-6 alkylamino, —C(O)(heterocycloalkyl), or cyano; where the aryl in aryloxy and aryl-C 1-6 alkyl are optionally substituted with 1, 2, or 3 groups independently selected from C 1-6 alkyl, halo, and halo-C 1-6 alkyl; and
R 8 is C 3 -C 8 -cycloalkyl;
to yield a compound of Formula I; and
b) optionally isolating the compound of Formula I.
20. The compound of claim 9 , where each R 7b is methyl; as a pharmaceutically acceptable salt or salts thereof; or a hydrate, solvate, stereoisomer, tautomer, or mixture thereof.
21. The compound of claim 1 , according to compound 82:
as a pharmaceutically acceptable salt or salts thereof; or
as a pharmaceutically acceptable salt or salts thereof and a stereoisomer thereof.
22. The compound of claim 1 , according to compound 84:
as a pharmaceutically acceptable salt or salts thereof; or
as a pharmaceutically acceptable salt or salts thereof and a stereoisomer thereof.
23. The compound of claim 1 , according to compound 95:
as a pharmaceutically acceptable salt or salts thereof; or
as a pharmaceutically acceptable salt or salts and a stereoisomer thereof.
24. The compound of claim 1 , according to compound 82:
as a pharmaceutically acceptable salt or salts and a stereoisomer thereof.
25. The compound of claim 1 , according to compound 84:
as a pharmaceutically acceptable salt or salts and a stereoisomer thereof.
26. The compound of claim 1 , according to compound 95:
as a pharmaceutically acceptable salt or salts and a stereoisomer thereof.
27. The method of claim 13 , wherein the pharmaceutical composition comprises compound 82:
as a pharmaceutically acceptable salt or salts thereof; or
as a pharmaceutically acceptable salt or salts and a stereoisomer thereof.
28. The method of claim 13 , wherein the pharmaceutical composition comprises compound 84:
as a pharmaceutically acceptable salt or salts thereof; or
as a pharmaceutically acceptable salt or salts and a stereoisomer thereof.
29. The method of claim 13 , wherein the pharmaceutical composition comprises compound 95:
as a pharmaceutically acceptable salt or salts thereof; or
as a pharmaceutically acceptable salt or salts and a stereoisomer thereof.