Disulfide prodrugs and linkers and stabilizers useful therefor

1. A compound having the structure:

or a pharmaceutically acceptable salt thereof;

wherein

X and Z are members independently selected from O, S and NR 23

wherein

R 23 is a member selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, and acyl;

R 1 is H, substituted or unsubstituted lower alkyl or C(O)R 8 , wherein R 8 is a member selected from NR 9 R 10 and OR 9 ,

in which

R 9 , and R 10 are members independently selected from H, substituted or unsubstituted alkyl and substituted or unsubstituted heteroalkyl;

R 2 is H or substituted or unsubstituted lower alkyl;

R 11 is C(O)NR 12 R 13 , in which

R 12 and R 13 are members independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl and substituted or unsubstituted aryl, and at least one of R 12 and R 13 comprises an enzymatically cleaveable disulfide group

R 4 and R 5 are members independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted heterocycloalkyl, halogen, NO 2 , NR 15 R 16 , NC(O)R 15 , OC(O)NR 15 R 16 , OC(O)OR 15 , C(O)R 15 , OR 15

wherein

R 15 and R 16 are independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted heterocycloalkyl and substituted or unsubstituted peptidyl, wherein R 15 and R 16 together with the nitrogen atom to which they are attached are optionally joined to form a substituted or unsubstituted heterocycloalkyl ring system having from 4 to 6 members, optionally containing two or more heteroatoms; and

X 1 is a leaving group.

2. The compound according to claim 1 , wherein said leaving group is a member selected from halogen, azide, alkylsulfonyl and arylsulfonyl.

3. The compound according to claim 1 , wherein R 1 is CO 2 CH 3 .

4. The compound according to claim 1 , wherein R 2 is CH 3 .

5. The compound according to claim 1 , wherein R 1 is CO 2 CH 3 , and R 2 is CH 3 .

6. The compound according to claim 5 , wherein R 4 and R 5 are members independently selected from H, halogen, NH 2 , O(CH 2 ) 2 NMe 2 and NO 2 .

7. The compound according to claim 1 , wherein at least one of R 4 and R 5 is other than a member selected from H and OCH 3 .

8. The compound according to claim 5 , wherein X is O; and Z is O.

9. The compound according to claim 1 , wherein a member selected from R 4 and R 5 is:

wherein

X 2 and Z 1 are members independently selected from O, S and NR 23 ;

R 17 and R 18 are members independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted heterocycloalkyl, halogen, NO 2 , NR 19 R 20 , NC(O)R 19 , OC(O)NR 19 , OC(O)OR 19 , C(O)R 19 , OR 19

wherein

R 19 and R 20 are independently selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted peptidyl, wherein R 19 and R 20 together with the nitrogen atom to which they are attached are optionally joined to form a substituted or unsubstituted heterocycloalkyl ring system having from 4 to 6 members, optionally containing two or more heteroatoms.

10. The compound according to claim 9 , wherein X 2 is O; and Z 1 is a member selected from O and NR 23 .

11. The compound according to claim 1 , wherein R 11 has the structure:

wherein

X 4 is a member selected from protected reactive functional groups, unprotected reactive functional groups, detectable labels and targeting agents;

L 3 is a linker selected from substituted or unsubstituted alkyl and substituted or unsubstituted heteroalkyl groups;

L 4 is a linker selected from substituted or unsubstituted alkyl and substituted or unsubstituted heteroalkyl groups; and

p and t are integers independently selected from 0 and 1.

12. The compound according to claim 11 , wherein L 4 is a substituted or unsubstituted ethylene moiety.

13. The compound according to claim 11 , wherein X 4 is a member selected from R 29 , COOR 29 , C(O)NR 29 , and C(O)NNR 29

wherein

R 29 is a member selected from substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl and substituted or unsubstituted heteroaryl.

14. The compound according to claim 13 , wherein R 29 is a member selected from: H; OH; NHNH 2 ;

wherein

R 30 is a member selected from substituted or unsubstituted alkyl terminated with a reactive functional group, substituted or unsubstituted heteroaryl terminated with a functional group and —(L 3 ) p X 4 , wherein each L 3 , X 4 and p are independently selected.

15. The compound according to claim 11 , wherein said compound is conjugated to another molecule via X 4 .

16. The compound according to claim 11 , wherein said detectable label is fluorophore.

17. The compound according to claim 11 , wherein said targeting agent is a biomolecule.

18. The compound according to claim 20 , wherein said biomolecule is a member selected from antibodies, receptors, peptides, lectins, saccharides, nucleic acids and combinations thereof.

19. A pharmaceutical formulation comprising a compound according to claim 1 and a pharmaceutically acceptable carrier.

20. A method of killing a cell, said method comprising administering to said cell an amount of a compound according to claim 1 sufficient to kill said cell.

21. A method of killing a carcinoma cell in a subject bearing said cell, said method comprising administering to said subject an amount of a compound according to claim 1 , sufficient to kill said cell.