Epothilone derivatives

1. A compound of the formula

wherein:

G is selected from the group consisting of alkyl; substituted alkyl; substituted aryl; a 4 to 7 membered monocyclic, 7 to 11 membered bicyclic, or 10 to 15 membered tricyclic saturated or unsaturated ring system having between 1 and 3 heteroatoms selected from nitrogen, oxygen, and sulfur;

W is O or NR 15 ;

X is O or H, H;

Y is selected from the group consisting of O; H, OR 16 ; OR 17 , OR 17 ; NOR 18 ; H, NHOR 19 ; H, NR 20 R 21 ; H, H; and CHR 22 ; wherein OR 17 , OR 17 can be a cyclic ketal;

Z 1 and Z 2 are independently CH 2 ;

B 1 and B 2 are independently selected from the group consisting of OR 24 , OCOR 25 , and O—C(═O)—NR 26 R 27 , and when B 1 is OH and Y is OH, H they can form a six-membered ring ketal or acetal;

R 1 , R 2 , R 3 , R 4 , R 5 , R 7 , R 13 , R 14 , R 18 , R 19 , R 20 , R 21 , R 22 , R 26 , and selected from the group consisting of H, alkyl, substituted alkyl, and aryl, and when R 1 and R 2 are alky, they can be joined to form a cycloalkyl; and when R 3 and R 4 are alkyl they can be joined to

form a cycloalkyl;

R 6 is methyl;

R 16 , R 17 , R 24 , and R 25 are selected from the group consisting of H, alkyl, and substituted alkyl;

R 11 , R 12 , R 32 , and R 33 are selected from the group consisting of H; alkyl; substituted alkyl; aryl; substituted aryl; cycloalkyl containing 1 to 3 rings and 3 to 7 carbons per ring which may be further fused with an unsaturated C 3 –C 7 carbocyclic ring; and a 4 to 7 membered monocyclic, 7 to 11 membered bicyclic, or 10 to 15 membered tricyclic saturated or unsaturated ring system having between 1 and 3 heteroatoms selected from nitrogen, oxygen, and sulfur;

R 8 is hydrogen or methyl;

R 15 is selected from the group consisting of H; alkyl; substituted alkyl; aryl; substituted aryl; cycloalkyl containing 1 to 3 rings and 3 to 7 carbons per ring which may be further fused with an unsaturated C 3 –C 7 carbocyclic ring; a 4 to 7 membered monocyclic, 7 to 11 membered bicyclic, or 10 to 15 membered tricyclic saturated or unsaturated ring system having between 1 and 3 heteroatoms selected from nitrogen, oxygen, and sulfur;

R 32 C═O, R 33 SO2, hydroxy, O-alkyl or O-substituted alkyl;

or a pharmaceutically acceptable salt thereof;

with the proviso that compounds wherein

W and X are both O; and

R 1 , R 2 and R 7 are H; and

R 3 and R 4 are methyl; and

G is 1-methyl-2-(substituted)-4-thiazolyl-ethenyl;

are excluded.

2. The compound of claim 1 , wherein: X is O and Y is O; or a pharmaceutically

acceptable salt thereof.

3. The compound of claim 2 , wherein: B 1 is OH and B 2 is OH; or a pharmaceutically acceptable salt thereof.

4. The compound of claim 3 , wherein W is O; or a pharmaceutically acceptable salt thereof.

5. The compound of claim 4 , wherein:

R 1 , R 2 , and R 7 are H; and

R 3 , R 4 , and R 5 are methyl;

or a pharmaceutically acceptable salt thereof.

6. The compound of claim 5 , wherein G is:

or a pharmaceutically acceptable salt thereof.

7. The compound of claim 6 , wherein R 11 is a 4 to 7 membered monocyclic saturated or unsaturated ring system having from 1 and 3 heteroatoms selected from nitrogen, oxygen, and sulfur; or a pharmaceutically acceptable salt thereof.

8. The compound of claim 3 , wherein W is NR 15 ; or a pharmaceutically acceptable salt thereof.

9. The compound of claim 8 , wherein:

R 1 , R 2 , and R 7 are H; and

R 3 , R 4 , and R 5 are methyl;

or a pharmaceutically acceptable salt thereof.

10. The compound of claim 9 , wherein G is:

or a pharmaceutically acceptable salt thereof.

11. The compound of claim 10 , wherein R 11 is a 4 to 7 membered monocyclic saturated or unsaturated ring system having from 1 and 3 heteroatoms selected from nitrogen, oxygen, and sulfur; or a pharmaceutically acceptable salt thereof.

12. The compound of claim 11 , wherein R 15 is H; or a pharmaceutically acceptable salt thereof.

13. A pharmaceutical composition comprising the compound of claim 1 or a pharmaceutically acceptable salt thereof; and a pharmaceutically acceptable vehicle or diluent.