1′-substituted-carba-nucleoside prodrugs for antiviral treatment

1. A compound of Formula I:

or a pharmaceutically acceptable salt or ester, thereof;

wherein:

R 1 is H, (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, or (C 2 -C 8 )alkynyl;

R 2 is OH or —OC(O)R 3 ;

each R 3 is independently H, OR 4 , NH(R 4 ), N(R 4 ) 2 , SR 4 , (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 3 -C 8 )carbocyclyl, (C 4 -C 8 ) carbocyclylalkyl, aryl(C 1 -C 8 )alkyl, heterocyclyl(C 1 -C 8 )alkyl, aryl, heterocyclyl or heteroaryl;

each R a , R 4 or R 6 is independently (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 3 -C 8 )carbocyclyl, (C 4 -C 8 )carbocyclylalkyl, aryl(C 1 -C 8 )alkyl, heterocyclyl(C 1 -C 8 )alkyl, (C 6 -C 20 )aryl, (C 2 -C 20 )heterocyclyl or heteroaryl;

one of W 1 or W 2 is

and the other of W 1 or W 2 is OR 4 or

each R c , R d or R 5 is independently H, (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 3 -C 8 )carbocyclyl, (C 4 -C 8 )carbocyclylalkyl, aryl(C 1 -C 8 )alkyl, heterocyclyl(C 1 -C 8 )alkyl, (C 6 -C 20 )aryl, (C 2 -C 20 )heterocyclyl or heteroaryl;

each R 8 is halogen, NR 11 R 12 , N(R 11 )OR 11 , NR 11 NR 11 R 12 , N 3 , NO, NO 2 , CHO, CN, —CH(═NR 11 ), —CH═NNHR 11 , —CH═N(OR 11 ), —CH(OR 11 ) 2 , —C(═O)NR 11 R 12 , —C(═S)NR 11 R 12 , —C(═O)OR 11 , (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 4 -C 8 )carbocyclylalkyl, (C 6 -C 20 )aryl, (C 2 -C 20 )heterocyclyl, heteroaryl, —C(═O)(C 1 -C 8 )alkyl, —S(O) n (C 1 -C 8 )alkyl, aryl(C 1 -C 8 )alkyl, OR 11 or SR 11 ;

each n is independently 0, 1, or 2;

each R 9 or R 10 is independently H, halogen, NR 11 R 12 , N(R 11 )OR 11 , NR 11 NR 11 R 12 , N 3 , NO, NO 2 , CHO, CN, —CH(═NR 11 ), —CH═NHNR 11 , —CH═N(OR 11 ), —CH(OR 11 ) 2 , —C(═O)NR 11 R 12 , —C(═S)NR 11 R 12 , —C(═O)OR 11 , R 11 , OR 11 or SR 11 ;

each R 11 or R 12 is independently H, (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 3 -C 8 )carbocyclyl, (C 4 -C 8 )carbocyclylalkyl, aryl(C 1 -C 8 )alkyl, heterocyclyl(C 1 -C 8 )alkyl, (C 6 -C 20 )aryl, (C 2 -C 20 )heterocyclyl, heteroaryl, —C(═O)(C 1 -C 8 )alkyl, —S(O) n (C 1 -C 8 )alkyl or R 11 and R 12 taken together with a nitrogen to which they are both attached form a 3 to 7 membered heterocyclic ring wherein any one carbon atom of said heterocyclic ring can optionally be replaced with —O—, —S(O) n — or —NR a —; and

wherein each (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 3 -C 8 )carbocyclyl, (C 4 -C 8 )carbocyclylalkyl, aryl(C 1 -C 8 )alkyl, heterocyclyl(C 1 -C 8 )alkyl, (C 6 -C 20 )aryl, (C 2 -C 20 )heterocyclyl, heteroaryl of R c , R d , R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 8 , R 11 or R 12 is, independently, optionally substituted with one or more halo, hydroxy, CN, N 3 , N(R a ) 2 , NH(R a ), NH 2 , C(O)N(R a ) 2 , C(O)NH(R a ), C(O)NH 2 , OC(O)N(R a ) 2 , OC(O)NH(R a ), OC(O)NH 2 , C(O)OR a , OC(O)OR a , C(O)R a , OC(O)R a , S(O) n R a , S(O) 2 N(R a ) 2 , S(O) 2 NH(R a ), S(O) 2 NH 2 , OR a or R a .

2. The compound of claim 1 represented by Formula II

or a pharmaceutically acceptable salt or ester, thereof,

wherein each R 5 is H.

3. The compound of claim 1 or 2 wherein R 1 is (C 1 -C 8 )alkyl.

4. The compound of any one of claims 1 - 3 wherein R 2 is OH.

5. The compound of claim 1 represented by Formula III:

or a pharmaceutically acceptable salt or ester, thereof;

wherein:

R 3 is (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 3 -C 8 )carbocyclyl, (C 4 -C 8 ) carbocyclylalkyl, aryl(C 1 -C 8 )alkyl, heterocyclyl(C 1 -C 8 )alkyl, aryl, heterocyclyl or heteroaryl;

each R a or R 6 is independently (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 3 -C 8 )carbocyclyl, (C 4 -C 8 )carbocyclylalkyl, aryl(C 1 -C 8 )alkyl, heterocyclyl(C 1 -C 8 )alkyl, (C 6 -C 20 )aryl, (C 2 -C 20 )heterocyclyl or heteroaryl;

one of W 1 or W 2 is

and the other of W 1 or W 2 is OR 4 or

each R c or R d is independently H, (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 3 -C 8 )carbocyclyl, (C 4 -C 8 )carbocyclylalkyl, aryl(C 1 -C 8 )alkyl, heterocyclyl(C 1 -C 8 )alkyl, (C 6 -C 20 )aryl, (C 2 -C 20 )heterocyclyl or heteroaryl;

each R 4 is (C 6 -C 20 )aryl or heteroaryl;

each R 8 is halogen, NR 11 R 12 , N(R 11 )OR 11 , NR 11 NR 11 R 12 , N 3 , —S(O) n (C 1 -C 8 )alkyl, OR 11 or SR 11 ;

each n is independently 0, 1, or 2;

each R 9 is independently H, halogen, NR 11 R 12 , N(R 11 )OR 11 , NR 11 NR 11 R 12 , N 3 , OR 11 or SR 11 ;

each R 11 or R 12 is independently H, (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 3 -C 8 )carbocyclyl, (C 4 -C 8 )carbocyclylalkyl, aryl(C 1 -C 8 )alkyl, heterocyclyl(C 1 -C 8 )alkyl, (C 6 -C 20 )aryl, (C 2 -C 20 )heterocyclyl, heteroaryl, —C(═O)(C 1 -C 8 )alkyl, —S(O) n (C 1 -C 8 )alkyl or R 11 and R 12 taken together with a nitrogen to which they are both attached form a 3 to 7 membered heterocyclic ring wherein any one carbon atom of said heterocyclic ring can optionally be replaced with —O—, —S(O) n — or —NR a —; and

wherein each (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 3 -C 8 )carbocyclyl, (C 4 -C 8 )carbocyclylalkyl, aryl(C 1 -C 8 )alkyl, heterocyclyl(C 1 -C 8 )alkyl, (C 6 -C 20 )aryl, (C 2 -C 20 )heterocyclyl, heteroaryl of R c , R d , R 3 , R 4 , R 6 , R 8 , R 11 or R 12 is, independently, optionally substituted with one or more halo, hydroxy, CN, N 3 , N(R a ) 2 , NH(R a ), NH 2 , C(O)N(R a ) 2 , C(O)NH(R a ), C(O)NH 2 , OC(O)N(R a ) 2 , OC(O)NH(R a ), OC(O)NH 2 , C(O)OR a , OC(O)OR a , C(O)R a , OC(O)R a , S(O) n R a , S(O) 2 N(R a ) 2 , S(O) 2 NH(R a ), S(O) 2 NH 2 , OR a or R a .

6. The compound of claim 1 represented by Formula IV:

or a pharmaceutically acceptable salt or ester, thereof;

wherein:

R 3 is (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 3 -C 8 )carbocyclyl or (C 4 -C 8 ) carbocyclylalkyl;

each R a is independently (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 3 -C 8 )carbocyclyl, (C 4 -C 8 )carbocyclylalkyl, aryl(C 1 -C 8 )alkyl, heterocyclyl(C 1 -C 8 )alkyl, (C 6 -C 20 )aryl, (C 2 -C 20 )heterocyclyl or heteroaryl;

each R c or R d is independently H or methyl;

R 4 is (C 6 -C 20 )aryl;

R 6 is (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 3 -C 8 )carbocyclyl or (C 4 -C 8 )carbocyclylalkyl;

each R 8 is halogen, NR 11 R 12 , N(R 11 )OR 11 , NR 11 NR 11 R 12 , N 3 , —S(O) n (C 1 -C 8 )alkyl, OR 11 or SR 11 ;

each n is independently 0, 1, or 2;

each R 9 is independently H, halogen, NR 11 R 12 , N(R 11 )OR 11 , NR 11 NR 11 R 12 , N 3 , OR 11 or SR 11 ;

each R 11 or R 12 is independently H, (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 3 -C 8 )carbocyclyl, (C 4 -C 8 )carbocyclylalkyl, aryl(C 1 -C 8 )alkyl, heterocyclyl(C 1 -C 8 )alkyl, (C 6 -C 20 )aryl, (C 2 -C 20 )heterocyclyl, heteroaryl, —C(═O)(C 1 -C 8 )alkyl, —S(O) n (C 1 -C 8 )alkyl or R 11 and R 12 taken together with a nitrogen to which they are both attached form a 3 to 7 membered heterocyclic ring wherein any one carbon atom of said heterocyclic ring can optionally be replaced with —O—, —S(O) n — or —NR a —; and

wherein each (C 1 -C 8 )alkyl, (C 2 -C 8 )alkenyl, (C 2 -C 8 )alkynyl, (C 3 -C 8 )carbocyclyl, (C 4 -C 8 )carbocyclylalkyl, aryl(C 1 -C 8 )alkyl, heterocyclyl(C 1 -C 8 )alkyl, (C 6 -C 20 )aryl, (C 2 -C 20 )heterocyclyl, heteroaryl of R 3 , R 4 , R 6 , R 8 , R 11 or R 12 is, independently, optionally substituted with one or more halo, hydroxy, CN, N 3 , N(R a ) 2 , NH(R a ), NH 2 , C(O)N(R a ) 2 , C(O)NH(R a ), C(O)NH 2 , OC(O)N(R a ) 2 , OC(O)NH(R a ), OC(O)NH 2 , C(O)OR a , OC(O)OR a , C(O)R a , OC(O)R a , S(O) n R a , S(O) 2 N(R a ) 2 , S(O) 2 NH(R a ), S(O) 2 NH 2 , OR a or R a .

7. The compound of claim 1 wherein the chirality of phosphorous is R.

8. The compound of claim 1 wherein the chirality of phosphorus is S.

9. The compound of any one of claim 1 , 5 , or 6 wherein R 3 is (C 1 -C 8 )alkyl.

10. The compound of any one of claim 1 , 5 , or 6 wherein one of R c or R d is H and the other of R c or R d is (C 1 -C 8 )alkyl.

11. The compound of any one of claim 1 , 5 , or 6 wherein R 6 is (C 1 -C 8 )alkyl.

12. The compound of claim 1 wherein R 8 is NR 11 R 12 or OR 11 .

13. The compound of any one of claim 1 , 5 , or 6 wherein R 9 is H or NR 11 R 12 .

14. The compound of claim 1 wherein each R 11 and R 12 is H.

15. The compound of any one of claim 1 , 5 , or 6 wherein R 8 is NH 2 and R 9 is H.

16. The compound of claim 1 wherein R 4 is (C 6 -C 20 )aryl.

17. The compound of claim 1 that is

or a pharmaceutically acceptable salt or ester thereof.

18. A pharmaceutical composition comprising a therapeutically effective amount of a compound or pharmaceutically acceptable salt or ester thereof of claim 1 or 17 and a pharmaceutically acceptable carrier.

19. The pharmaceutical composition of claim 18 further comprising at least one additional therapeutic agent selected from the group consisting of interferons, ribavirin or its analogs, HCV NS3 protease inhibitors, NS5a inhibitors, alpha-glucosidase 1 inhibitors, hepatoprotectants, mevalonate decarboxylase antagonists, antagonists of the renin-angiotensin system, other anti-fibrotic agents, nucleoside or nucleotide inhibitors of HCV NS5B polymerase, non-nucleoside inhibitors of HCV NS5B polymerase, HCV NS5A inhibitors, TLR-7 agonists, cyclophillin inhibitors, HCV IRES inhibitors, pharmacokinetic enhancers, and other drugs for treating HCV.

20. A method of inhibiting HCV polymerase comprising administering to a mammal in need thereof a therapeutically effective amount of a compound or pharmaceutically acceptable salt or ester thereof of claim 1 or 17 .

21. A method of treating a viral infection caused by Hepatitis C virus comprising administering to a mammal in need thereof a therapeutically effective amount of a compound or pharmaceutically acceptable salt or ester thereof or pharmaceutical composition of claim 1 or 17 .

22. The method of claim 21 further comprising administering at least one additional therapeutic agent selected from the group consisting of interferons, ribavirin or its analogs, HCV NS3 protease inhibitors, NS5a inhibitors, alpha-glucosidase 1 inhibitors, hepatoprotectants, mevalonate decarboxylase antagonists, antagonists of the renin-angiotensin system, other anti-fibrotic agents, nucleoside or nucleotide inhibitors of HCV NS5B polymerase, non-nucleoside inhibitors of HCV NS5B polymerase, HCV NS5A inhibitors, TLR-7 agonists, cyclophillin inhibitors, HCV IRES inhibitors, pharmacokinetic enhancers, and other drugs for treating HCV.