Phosphoramide compounds

1. A compound a compound of formula I:

wherein:

R 1 is an organic releasing group comprising a quinone ring;

R a , R b , R c , and R d are each independently hydrogen, (C 1 –C 6 )alkyl, or —CH 2 CH 2 X; and

each X is independently halo, (C 1 –C 6 )alkylsulfonyl, halo(C 1 –C 6 )alkylsulfonyl, or arylsulfonyl, wherein each aryl is optionally substituted with one or more (e.g. 1, 2, 3, or 4) halo, (C 1 –C 6 )alkyl, halo(C 1 –C 6 )alkyl, (C 1 –C 6 )alkoxy, (C 1 –C 6 )alkanoyl, (C 1 –C 6 )alkanoyloxy, (C 1 –C 6 )alkoxycarbonyl, cyano, nitro, or trifluoromethoxy;

provided at least two of R a , R b , R c , and R d are —CH 2 CH 2 X;

or a pharmaceutically acceptable salt thereof.

2. The compound of claim 1 wherein R 1 is a group of formula (II):

wherein R c is hydrogen, halo, (C 1 –C 6 )alkyl, halo(C 1 –C 6 )alkyl, (C 1 –C 6 )alkoxy, (C 1 –C 6 )alkanoyloxy, cyano, nitro, or (C 1 –C 6 )alkylthio; and

wherein the benz ring is optionally substituted by one or more (e.g. 1, 2, 3, or 4) hydroxy, halo, (C 1 –C 6 )alkyl, halo(C 1 –C 6 )alkyl, (C 1 –C 6 )alkoxy, (C 1 –C 6 )alkylthio; (C 1 –C 6 )alkanoyl, (C 1 –C 6 )alkanoyloxy, (C 1 –C 6 )alkoxycarbonyl, cyano, nitro, mercapto, trifluoromethoxy, or NR f R g ;

wherein each R f and R g is independently hydrogen, (C 1 –C 6 )alkyl, (C 1 –C 6 )alkanoyl, phenyl, benzyl, or phenethyl; or R f and R g together with the nitrogen to which they are attached are pyrrolidino, piperidino or morpholino.

3. The compound of claim 1 wherein X is bromo, chloro, mesyl, trifluoromethylsulfonyl, or tosyl.

4. The compound of claim 1 wherein X is bromo.

5. The compound of claim 2 wherein R c is hydrogen, halo, methyl, or methylthio.

6. The compound of claim 1 wherein R a is (C 1 –C 6 )alkyl.

7. The compound of claim 1 wherein R c is (C 1 –C 6 )alkyl.

8. The compound of claim 1 wherein R a and R b are each independently —CH 2 CH 2 X.

9. The compound of claim 1 wherein R c , and R d are each independently —CH 2 CH 2 X.

10. The compound of claim 1 wherein R b and R d are each independently —CH 2 CH 2 X.

11. The compound of claim 1 wherein R a is methyl.

12. The compound of claim 1 wherein R c is methyl.

13. The compound of claim 1 wherein R a and R b are each —CH 2 CH 2 Br.

14. The compound of claim 1 wherein R c , and R d are each —CH 2 CH 2 Br.

15. The compound of claim 1 wherein R b and R d are each —CH 2 CH 2 Br.

16. The compound of claim 1 wherein R a and R b are each independently —CH 2 CH 2 Cl.

17. The compound of claim 1 wherein R c , and R d are each independently —CH 2 CH 2 Cl.

18. The compound of claim 1 wherein R b and R d are each independently —CH 2 CH 2 Cl.

19. The compound of claim 1 which is:

2-(1 ,4-naphthoquinonyl)methyl N,N-bis(2-chloroethyl) phosphorodiamidate;

2-(3-methyl-1,4-naphthoquinonyl)methyl N,N-bis(2-chloroethyl) phosphorodiamidate;

2-(3-thiomethyl-1,4-naphthoquinonyl)methyl N,N-bis(2-chloroethyl) phosphorodiamidate;

2-(3-bromo-1,4-naphthoquinonyl)methyl N,N-bis(2-chloroethyl) phosphorodiamidate;

2-(1,4-naphthoquinonyl)methyl N,N-bis(2-bromoethyl) phosphorodiamidate;

2-(3-methyl-1,4-naphthoquinonyl)methyl N,N-bis(2-bromoethyl) phosphorodiamidate;

2-(1,4-naphthoquinonyl)methyl bis[N-(2-chloroethyl)] phosphorodiamidate;

2-(1,4-naphthoquinonyl)methyl bis[N-methyl-N-(2-bromoethyl)]phosphorodiamidate;

2-(3-methyl-1,4-naphthoquinonyl)methyl bis[N-methyl-N-(2-bromo ethyl)]phosphorodiamidate;

2-(1,4-naphthoquinonyl)methyl bis[N-methyl-N-(2-chloroethyl)] phosphorodiamidate; or a pharmaceutically acceptable salt thereof.

20. A pharmaceutical composition comprising a compound of claim 1 , in combination with a pharmaceutically acceptable diluent or carrier.

21. A method for preparing a compound of formula I as described in claim 1 , wherein R 1 is a group of formula II

comprising oxidizing a corresponding compound of formula I wherein R 1 is a group of formula VI

22. The compound of claim 1 , wherein the organic releasing group is capable of releasing a group of formula —O—P(═O)(NR a R b )(NR c R d ) in vivo from the compound of formula I.