Compounds useful for treating neurodegenerative disorders

1. A compound of formula IV-a provided in greater than 80% chemical purity:

or a pharmaceutically acceptable salt thereof, wherein:

G is S, CH 2 , NR, or O;

R 1 and R 2 are each independently halogen, R, OR, a protected hydroxyl group, SR, a protected thiol group, N(R) 2 , or a protected amino group, or R 1 and R 2 are taken together to form a 3-7 membered saturated, partially unsaturated, or aryl ring having 0-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur;

each R is independently hydrogen, an optionally substituted C 1-6 aliphatic group, or an optionally substituted 3-8 membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, wherein:

two R on the same nitrogen atom are optionally taken together with said nitrogen atom to form a 3-8 membered saturated, partially unsaturated, or aryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur;

R 3 , R 4 , R 7 , and R 8 are each independently selected from halogen, R, OR, a protected hydroxyl group, SR protected thiol group, SO 2 R, OSO 2 R, N(R) 2 , a protected amino group, NR(CO)R, NR(CO)(CO)R, NR(CO)N(R) 2 , NR(CO)OR, (CO)OR, O(CO)R, (CO)N(R) 2 , or O(CO)N(R) 2 ;

R 5 is T-C(R′) 3 , T-C(R′) 2 C(R″) 3 , R, OR, a protected hydroxyl group, SR, a protected thiol group, SO 2 R, OSO 2 R, N(R) 2 , a protected amino group, NR(CO)R, NR(CO)(CO)R, NR(CO)N(R) 2 , NR(CO)OR, (CO)OR, O(CO)R, (CO)N(R) 2 , or O(CO)N(R) 2 , or:

each T is independently a valence bond or an optionally substituted straight or branched, saturated or unsaturated, C 1-6 alkylidene chain wherein up to two methylene units of T are optionally and independently replaced by —O—, —N(R)—, —S—, —C(O)—, —S(O)—, or —S(O) 2 —;

each R′ and R″ is independently selected from R, OR, SR, SO 2 R, OSO 2 R, N(R) 2 , NR(CO)R, NR(CO)(CO)R, NR(CO)N(R) 2 , NR(CO)OR, (CO)OR, O(CO)R, (CO)N(R) 2 , or O(CO)N(R) 2 ;

R 9 and R 9′ are each independently selected from halogen, R, OR, SR, or N(R) 2 , or R 9 and R 9′ are taken together to form a 3-7 membered saturated or partially unsaturated ring having 0-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur;

Q is a valence bond or an optionally substituted straight or branched, saturated or unsaturated, C 1-6 alkylidene chain wherein up to two methylene units of Q are optionally and independently replaced by —O—, —N(R)—, —S—, —C(O)—, —S(O)—, or —S(O) 2 —; and

R 10 is R, a protected hydroxyl group, a protected thiol group, a protected amino group, an optionally substituted 3-8 membered saturated, partially unsaturated, or aryl monocyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, an optionally substituted 8-10 membered saturated, partially unsaturated, or aryl bicyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, a detectable moiety selected from the group consisting of radioisotopes, mass-tags, fluorescent labels, biotin, and antigen labels, a polymer residue selected from the group consisting of poly(alkylene oxides), a peptide, or a sugar-containing or sugar-like moiety selected from the group consisting of cyclic and acyclic cyclitols, glycosides, arabinopyranoside, xylopyranoside, or erythritol.

2. The compound according to claim 1 , wherein R 1 and R 2 are taken together to form a 3-6 membered saturated carbocyclic ring and R 7 is —OH.

3. The compound according to claim 1 , wherein said compound is selected from:

4. The compound according claim 1 , wherein said compound is selected from:

5. A compound of formula IV-a:

or a pharmaceutically acceptable salt thereof, wherein:

G is S, CH 2 , NR, or O;

R 1 and R 2 are each independently halogen, R, OR, a protected hydroxyl group, SR, a protected thiol group, N(R) 2 , or a protected amino group, or R 1 and R 2 are taken together to form a 3-7 membered saturated, partially unsaturated, or aryl ring having 0-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur;

each R is independently hydrogen, an optionally substituted C 1-6 aliphatic group, or an optionally substituted 3-8 membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, wherein:

two R on the same nitrogen atom are optionally taken together with said nitrogen atom to form a 3-8 membered saturated, partially unsaturated, or aryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur;

R 3 , R 4 , R 7 , and R 8 are each independently selected from halogen, R, OR, a protected hydroxyl group, SR, a protected thiol group, SO 2 R, OSO 2 R, N(R) 2 , a protected amino group, NR(CO)R, NR(CO)(CO)R, NR(CO)N(R) 2 , NR(CO)OR, (CO)OR, O(CO)R, (CO)N(R) 2 , or O(CO)N(R) 2 ;

R 5 is T-C(R′) 3 , T-C(R′) 2 C(R″) 3 , R, OR, a protected hydroxyl group, SR, a protected thiol group, SO 2 R, OSO 2 R, N(R) 2 , a protected amino group, NR(CO)R, NR(CO)(CO)R, NR(CO)N(R) 2 , NR(CO)OR, (CO)OR, O(CO)R, (CO)N(R) 2 , or O(CO)N(R) 2 , or:

each T is independently a valence bond or an optionally substituted straight or branched, saturated or unsaturated, C 1-6 alkylidene chain wherein up to two methylene units of T are optionally and independently replaced by —O—, —N(R)—, —S—, —C(O)—, —S(O)—, or —S(O) 2 —;

each R′ and R″ is independently selected from R, OR, SR, SO 2 R, OSO 2 R, N(R) 2 , NR(CO)R, NR(CO)(CO)R, NR(CO)N(R) 2 , NR(CO)OR, (CO)OR, O(CO)R, (CO)N(R) 2 , or O(CO)N(R) 2 ;

R 9 and R 9′ are each independently selected from halogen, R, OR, SR, or N(R) 2 , or R 9 and R 9′ are taken together to form a 3-7 membered saturated or partially unsaturated ring having 0-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur;

Q is a valence bond or an optionally substituted straight or branched, saturated or unsaturated, C 1-6 alkylidene chain wherein up to two methylene units of Q are optionally and independently replaced by —O—, —N(R)—, —S—, —C(O)—, —S(O)—, or —S(O) 2 —; and

R 10 is R, a protected hydroxyl group, a protected thiol group, a protected amino group, an optionally substituted 3-8 membered saturated, partially unsaturated, or aryl monocyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, an optionally substituted 8-10 membered saturated, partially unsaturated, or aryl bicyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, a detectable moiety selected from the group consisting of radioisotopes, mass-tags, fluorescent labels, biotin, and antigen labels, a polymer residue selected from the group consisting of poly(alkylene oxides), a peptide, or a sugar-containing or sugar-like moiety selected from the group consisting of cyclic and acyclic cyclitols, glycosides, arabinopyranoside, xylopyranoside, or erythritol,

wherein said compound contains no more than about 10.0 area percent, by HPLC chromatogram, of other compounds present in black cohosh root relative to the total area of the HPLC chromatogram.

6. The compound according to claim 5 , wherein said compound contains no more than about 10.0 area percent, by HPLC chromatogram, of one or more of acteol, acetylacteol, 26-deoxyacteol, cimigenol, actein, 26-deoxyactein, and cimicifugoside relative to the total area of the HPLC chromatogram.

7. A composition comprising a compound according to claim 1 , and a pharmaceutically acceptable carrier, adjuvant, or vehicle.

8. A composition comprising a compound according to claim 5 , and a pharmaceutically acceptable carrier, adjuvant, or vehicle.

9. An extract of black cohosh root wherein said extract comprises at least 10% by weight of a compound of formula IV-a:

or a pharmaceutically acceptable salt thereof, wherein:

G is S, CH 2 , NR, or O;

R 1 and R 2 are each independently halogen, R, OR, a protected hydroxyl group, SR, a protected thiol group, N(R) 2 , or a protected amino group, or R 1 and R 2 are taken together to form a 3-7 membered saturated, partially unsaturated, or aryl ring having 0-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur;

each R is independently hydrogen, an optionally substituted C 1-6 aliphatic group, or an optionally substituted 3-8 membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, wherein:

two R on the same nitrogen atom are optionally taken together with said nitrogen atom to form a 3-8 membered saturated, partially unsaturated, or aryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur;

R 3 , R 4 , R 7 , and R 8 are each independently selected from halogen, R, OR, a protected hydroxyl group, SR, a protected thiol group, SO 2 R, OSO 2 R, N(R) 2 , a protected amino group, NR(CO)R, NR(CO)(CO)R, NR(CO)N(R) 2 , NR(CO)OR, (CO)OR, O(CO)R, (CO)N(R) 2 , or O(CO)N(R) 2 ;

R 5 is T-C(R′) 3 , T-C(R′) 2 C(R″) 3 , R, OR, a protected hydroxyl group, SR, a protected thiol group, SO 2 R, OSO 2 R, N(R) 2 , a protected amino group, NR(CO)R, NR(CO)(CO)R, NR(CO)N(R) 2 , NR(CO)OR, (CO)OR, O(CO)R, (CO)N(R) 2 , or O(CO)N(R) 2 , or:

each T is independently a valence bond or an optionally substituted straight or branched, saturated or unsaturated, C 1-6 alkylidene chain wherein up to two methylene units of T are optionally and independently replaced by —O—, —N(R)—, —S—, —C(O)—, —S(O)—, or —S(O) 2 —;

each R′ and R″ is independently selected from R, OR, SR, SO 2 R, OSO 2 R, N(R) 2 , NR(CO)R, NR(CO)(CO)R, NR(CO)N(R) 2 , NR(CO)OR, (CO)OR, O(CO)R, (CO)N(R) 2 , or O(CO)N(R) 2 ;

R 9 and R 9′ are each independently selected from halogen, R, OR, SR, or N(R) 2 , or R 9 and R 9′ are taken together to form a 3-7 membered saturated or partially unsaturated ring having 0-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur;

Q is a valence bond or an optionally substituted straight or branched, saturated or unsaturated, C 1-6 alkylidene chain wherein up to two methylene units of Q are optionally and independently replaced by —O—, —N(R)—, —S—, —C(O)—, —S(O)—, or —S(O) 2 —; and

R 10 is R, a protected hydroxyl group, a protected thiol group, a protected amino group, an optionally substituted 3-8 membered saturated, partially unsaturated, or aryl monocyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, an optionally substituted 8-10 membered saturated, partially unsaturated, or aryl bicyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, a detectable moiety selected from the group consisting of radioisotopes, mass-tags, fluorescent labels, biotin, and antigen labels, a polymer residue selected from the group consisting of poly(alkylene oxides), a peptide, or a sugar-containing or sugar-like moiety selected from the group consisting of cyclic and acyclic cyclitols, glycosides, arabinopyranoside, xylopyranoside, or erythritol.

10. The extract according to claim 9 , wherein said extract comprises from about 10% by weight to about 50% by weight of the compound of formula IV-a.

11. The compound according to claim 1 , wherein the compound is of formula IV-b:

or a pharmaceutically acceptable salt thereof.

12. The compound according to claim 1 , wherein:

G is O; and R 1 and R 2 are each independently R or OR.

13. The compound according to claim 1 , wherein R 1 and R 2 are each independently R wherein R is hydrogen or an optionally substituted C 1-6 aliphatic group.

14. The compound according to claim 1 , wherein R 1 and R 2 are taken together to form a 3-6 membered saturated, partially unsaturated, or aryl ring having 0-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur.

15. The compound according to claim 1 , wherein:

R 5 is T-C(R′) 3 or T-C(R′) 2 C(R″) 3 ;

each T is independently a valence bond or a straight or branched C 1-4 alkylidene chain wherein one methylene unit of T is optionally replaced by —O—, —N(R)—, or —S—; and

each R′ and R″ is independently R, OR, OC(O)R, SR, or N(R) 2 .

16. The compound according to claim 1 , wherein:

Q is a an optionally substituted straight or branched, saturated or unsaturated, C 1-2 alkylidene chain wherein up to one methylene unit of Q is optionally replaced by —O—, —N(R)—, or —S—; and

R 10 is a glycoside.

17. The compound according to claim 1 , wherein Q is —O— and R 10 is an arabinopyranoside or a xylopyranoside.

18. The compound according to claim 1 , wherein the compound is provided in greater than 90% chemical purity.