Acyclic antivirals

1. A compound of Formula (I), or a pharmaceutically acceptable salt thereof, having the structure:

wherein:

B 1 is selected from the group consisting of: an optionally substituted

an optionally substituted

an optionally substituted

an optionally substituted

an optionally substituted

an optionally substituted

an optionally substituted

an optionally substituted

an optionally substituted

an optionally substituted

and an optionally substituted

R 1 and R 2 are each independently selected from the group consisting of O − , —OH, an optionally substituted —O—C 1-24 alkyl, an optionally substituted —O—C 2-24 alkenyl, an optionally substituted —O—C 2-24 alkynyl, an optionally substituted —O—C 3-6 cycloalkyl, an optionally substituted —O—C 3-6 cycloalkenyl, an optionally substituted —O-aryl, an optionally substituted —O-heteroaryl, an optionally substituted —O-aryl(C 1-6 alkyl), an optionally substituted —O—(CR 4 R 5 ) p —O—C 1-24 alkyl, an optionally substituted —O—(CR 6 R 7 ) q —O—C 1-24 alkenyl,

an optionally substituted N-linked amino acid and an optionally substituted N-linked amino acid ester derivative; or

R 1 is

and R 2 is O − or OH; or

R 1 and R 2 are taken together to form a moiety selected from the group consisting of an optionally substituted

and an optionally substituted

wherein the phosphorus and the moiety form a six-membered or ten-membered ring system;

R 3a is hydroxy(C 1-4 alkyl)-;

R 3b is selected from the group consisting of hydrogen, halogen, an unsubstituted C 1-4 alkyl, an unsubstituted C 3-6 cycloalkyl, cyano, halogen(C 1-4 alkyl), hydroxy(C 1-4 alkyl), alkoxy(C 1-4 alkyl), acyl(C 1-4 alkyl) and cyano(C 1-4 alkyl);

each R 4 , each R 5 , each R 6 and each R 7 are independently hydrogen, an optionally substituted C 1-24 alkyl or alkoxy;

R 8 , R 9 , R 11 and R 12 are each independently selected from the group consisting of hydrogen, an optionally substituted C 1-24 alkyl and an optionally substituted aryl;

R 10 and R 13 are each independently selected from the group consisting of hydrogen, an optionally substituted C 1-24 alkyl, an optionally substituted aryl, an optionally substituted —O—C 1-24 alkyl, an optionally substituted —O-aryl, an optionally substituted —O-heteroaryl and an optionally substituted —O-monocyclic heterocyclyl;

R 14 is selected from the group consisting of hydrogen, an optionally substituted C 1-24 -alkyl and an optionally substituted aryl;

R 15 and R 16 are each independently selected from the group consisting of —C≡CN, an optionally substituted C 2-8 organylcarbonyl, an optionally substituted C 2-8 alkoxycarbonyl and an optionally substituted C 2-8 organylaminocarbonyl;

R 17 is selected from the group consisting of hydrogen, an optionally substituted C 1-24 -alkyl, an optionally substituted C 2-24 alkenyl, an optionally substituted C 2-24 alkynyl, an optionally substituted C 3-6 cycloalkyl and an optionally substituted C 3-6 cycloalkenyl;

R 19 , R 20 and R 21 are each independently absent or hydrogen;

m is 0 or 1;

n is 1 or 2;

p and q are each independently selected from the group consisting of 1, 2 and 3;

r is 1 or 2;

s is 0 or 1;

Z 1 is oxygen (O) or sulfur (S).

2. The compound of claim 1 , wherein B 1 is selected from the group consisting of: an unsubstituted

an unsubstituted

an unsubstituted

an unsubstituted

an unsubstituted

an unsubstituted

an unsubstituted

an unsubstituted

an unsubstituted

an unsubstituted

and an unsubstituted

3. The compound of claim 1 , wherein R 1 and R 2 are each independently selected from the group consisting of O − , —OH, an optionally substituted —O-aryl, an optionally substituted —O-heteroaryl, an optionally substituted N-linked amino acid and an optionally substituted N-linked amino acid ester derivative.

4. The compound of claim 1 , wherein R 3b is hydrogen an unsubstituted C 1-4 alkyl, halogen(C 1-4 alkyl), hydroxy(C 1-4 alkyl), alkoxy(C 1-4 alkyl), acyl(C 1-4 alkyl) or cyano(C 1-4 alkyl).

5. The compound of claim 1 , wherein and R 3b is hydrogen.

6. The compound of claim 1 , wherein R 3b is selected from the group consisting of hydrogen, fluoro, CH 3 , CH 2 F, CHF 2 , CH 2 OH and —CH 2 —O—CH 3 .

7. The compound of claim 1 , wherein R 3a is CH 3 OH.

8. The compound of claim 1 , wherein n is 1.

9. The compound of claim 1 , wherein m is 1.

10. The compound of claim 1 selected from the group consisting of:

or a pharmaceutically acceptable salt of any of the foregoing.

11. The compound of claim 1 selected from the group consisting of:

or a pharmaceutically acceptable salt of any of the foregoing.

12. A pharmaceutical composition comprising an effective amount of a compound of claim 1 , or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier, diluent, excipient or combination thereof.

13. A method of ameliorating or treating a HBV and/or HDV infection, comprising administering to a subject suffering from the HBV and/or HDV infection an effective amount of a compound of claim 1 , or a pharmaceutically acceptable salt thereof.

14. A method of ameliorating or treating a HIV infection comprising administering to a subject suffering from the HIV infection an effective amount of a compound of claim 1 , or a pharmaceutically acceptable salt thereof.

15. The compound of claim 1 , wherein B 1 is an optionally substituted

16. The compound of claim 1 , wherein B 1 is an optionally substituted

17. The compound of claim 1 , wherein B 1 is an optionally substituted

18. The compound of claim 1 , wherein B 1 is an optionally substituted

19. The compound of claim 1 , wherein B 1 is an optionally substituted

20. The compound of claim 1 , wherein B 1 is an optionally substituted

21. The compound of claim 1 , wherein B 1 is an optionally substituted

22. The compound of claim 1 , wherein B 1 is an optionally substituted

23. The compound of claim 1 , wherein B 1 is an optionally substituted

24. The compound of claim 1 , wherein B 1 is an optionally substituted

25. The compound of claim 1 , wherein B 1 is an optionally substituted