Phosphono-pent-2-en-1-yl nucleosides and analogs

1. A compound of Formula IA or IB:

or a pharmaceutically acceptable salt thereof,

wherein each R is independently hydrogen, a monovalent cation or a lipophilic group and B is a purine or pyrimidine base or an analog thereof, wherein at least one R is a lipophilic group other than methyl or ethyl.

2. The compound of claim 1 , wherein the compound has formula

3. The compound of claim 1 , wherein R is hydrogen, a monovalent cation, a substituted or unsubstituted C 8 -C 24 alkyl or substituted or unsubstituted C 8 -C 24 alkenyl having from 1 to 6 double bonds, wherein substituents when present are selected from one or more halogen, alkyl, —OH, —SH, cycloalkyl, or epoxide.

4. The compound of claim 1 , wherein R has formula:

wherein:

R 1 and R 1a are independently —H, —O(C 1 -C 24 )alkyl, —O(C 1 -C 24 )alkenyl, —O(C 1 -C 24 )acyl, —S(C 1 -C 24 )alkyl, —S(C 1 -C 24 )alkenyl, or —S(C 1 -C 24 )acyl, wherein at least one of R 1 and R 1a are not —H, and wherein the alkenyl or acyl moieties optionally have 1 to 6 double bonds,

R 2 and R 2a are independently —H, —O(C 1 -C 7 )alkyl, —O(C 1 -C 7 )alkenyl, —S(C 1 -C 7 )alkyl, —S(C 1 -C 7 )alkenyl, —O(C 1 -C 7 )acyl, —S(C 1 -C 7 )acyl, —N(C 1 -C 7 )acyl, —NH(C 1 -C 7 )alkyl, —N((C 1 -C 7 )alkyl) 2 , oxo, halogen, —NH 2 , —OH, or —SH;

R 6 , when present, is:

m is an integer from 0 to 6;

and wherein R 1 , R 1a , R 2 , R 2a , and R 7a are optionally substituted with one to four substituents, each independently selected from alkyl, alkenyl, alkynyl, halo, hydroxyl, pseudohalo, amino, nitro, cycloalkyl, heterocyclyl, aryl and heteroaryl.

5. The compound of claim 1 , wherein R has formula:

6. The compound of claim 1 , wherein R has formula:

7. The compound of claim 1 , wherein R has formula:

8. The compound of claim 1 , wherein R is hexadecyloxypropyl, octadecyloxypropyl, or octadecyloxyethyl.

9. The compound of claim 1 , wherein R is acetyl, valyl, dipivoxil, bis(pivaloyloxymethyl) or disoproxil.

10. The compound of claim 1 , wherein B is

wherein R 3 is H, C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 3-6 cycloalkyl, hydroxy, halo, aryl or heteroaryl;

R 6 is H or C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl or cycloalkyl;

R 7 is H, hydroxy, halo, C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, cycloalkyl or NR 4 R 5 ;

R 8 is H, C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl or cycloalkyl;

R 9 is H, C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, cycloalkyl, halo or NR 4 R 5 ; and

R 4 and R 5 are each independently H, C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, or C 3-6 cycloalkyl.

11. The compound of claim 1 , wherein, B is thymin-1-yl, cytosine-1-yl, uracil-1-yl, adenine-9-yl or guanine-9-yl.

12. The compound of claim 1 , wherein B is selected from:

13. The compound of claim 1 , wherein the compound is selected from 5-phosphono-pent-2-en- 1-yl adenine, 5-phosphono-pent-2-en-1-yl cytosine, 5-phosphono-pent-2-en-1-yl guanine, 5-phosphono-pent-2-en-1-yl thymine and 5-phosphono-pent-2-en-1-yl uracil.

14. The compound of claim 1 , wherein the compound is selected from:

15. A pharmaceutical composition comprising a compound of claim 1 and a pharmaceutically acceptable carrier.

16. A method for treating, a viral infection, wherein the method comprises administering an effective amount of a compound of claim 1 .

17. The method of claim 16 , wherein the viral infection is a caused by influenza, hepatitis B virus, hepatitis C virus, cytomegalovirus, Varicella zoster virus, Herpes simplex virus types and 2, Epstein-Barr virus, Herpes type 6 and type 8, Varicella zoster virus, Epstein Barr virus infections, retroviral infections, orthopox viruses, vaccinia, ebola virus, adenovirus and papilloma virus.

18. The method of claim 16 , wherein the viral infection is drug resistant Hepatitis B.