Carbocyclic nucleoside reverse transcriptase inhibitors

1. A compound of structural Formula I

or a pharmaceutically acceptable salt thereof, wherein:

R is

X is —N— or —C(H)—;

R 7 is —CH, —N, —C 1-6 alkyl or —C-aryl;

R 1 is H,

R 2 is H or —CH 2 —O—C 1-6 alkyl;

R 3 is halo, —NH 2 , oxo (═O), —O—C 1-6 alkyl or —O—C(O)—N(phenyl) 2 ;

R 4 is halo or —NR a R b ;

R a and R b are each independently selected from —H, —C 1-6 alkyl or —C(O)—C 1-6 alkyl;

R 5 is —H or —C(O)-phenyl; and

R 6 is —H or —C(O)-phenyl.

2. The compound of claim 1 or a pharmaceutically acceptable salt thereof wherein:

R 1 is H,

R 2 is H or —CH 2 —O—C 1-3 alkyl;

R 3 is halo, —NH 2 , oxo, —O—C 1-3 alkyl or —O—C(O)—N(phenyl) 2 ; and

R 4 is halo, —NH 2 or —NH—C(O)—C 1-3 alkyl.

3. The compound of claim 1 that is:

(1S,2S,4R)-4-(6-chloro-2-fluoro-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol and (1R,2R,4S)-4-(6-chloro-2-fluoro-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol;

(1S,2S,4R)-4-(6-amino-2-fluoro-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol and (1R,2R,4S)-4-(6-amino-2-fluoro-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol;

(1S,2S,4R)-4-(2-amino-6-chloro-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol and (1R,2R,4S)-4-(2-amino-6-chloro-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol;

(1S,2S,4R)-4-(2,6-dichloro-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol and (1R,2R,4S)-4-(2,6-dichloro-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol;

(1S,2S,4R)-4-(6-amino-2-chloro-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol and (1R,2R,4S)-4-(6-amino-2-chloro-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol;

(1S,2S,4R)-4-(6-amino-2-chloro-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol or (1R,2R,4S)-4-(6-amino-2-chloro-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol;

(1S,2S,4R)-4-(6-amino-2-chloro-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol or (1R,2R,4S)-4-(6-amino-2-chloro-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol;

(1S,2S,4R)-4-(2,4-dichloro-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol and (1R,2R,4S)-4-(2,4-dichloro-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol;

(1S,2S,4R)-4-(4-amino-2-chloro-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol and (1R,2R,4S)-4-(4-amino-2-chloro-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol;

2-amino-9-((1R,3 S,4S)-3-ethynyl-4-hydroxy-3-(hydroxymethyl)cyclopentyl)-1,9-dihydro-6H-purin-6-one and 2-amino-9-((1S,3R,4R)-3-ethynyl-4-hydroxy-3-(hydroxymethyl)cyclopentyl)-1,9-dihydro-6H-purin-6-one;

2-amino-9-((1R,3 S,4S)-3-ethynyl-4-hydroxy-3-(hydroxymethyl)cyclopentyl)-1,9-dihydro-6H-purin-6-one or 2-amino-9-((1S,3R,4R)-3-ethynyl-4-hydroxy-3-(hydroxymethyl)cyclopentyl)-1,9-dihydro-6H-purin-6-one;

2-amino-9-((1R,3 S,4S)-3-ethynyl-4-hydroxy-3-(hydroxymethyl)cyclopentyl)-1,9-dihydro-6H-purin-6-one or 2-amino-9-((1S,3R,4R)-3-ethynyl-4-hydroxy-3-(hydroxymethyl)cyclopentyl)-1,9-dihydro-6H-purin-6-one;

(1S,2S,4R)-4-(2-amino-6-ethoxy-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol and (1R,2R,4S)-4-(2-amino-6-ethoxy-9H-purin-9-yl)-2-ethynyl-2-(hydroxymethyl)cyclopentan-1-ol;

1-((1R,3 S,4S)-3-ethynyl-4-hydroxy-3-(hydroxymethyl)cyclopentyl)-5-methylpyrimidine-2,4(1H,3H)-dione and 1-((1S,3R,4R)-3-ethynyl-4-hydroxy-3-(hydroxymethyl)cyclopentyl)-5-methylpyrimidine-2,4(1H,3H)-dione;

4-amino-1-((1R,3 S,4 S)-3-ethynyl-4-hydroxy-3-(hydroxymethyl)cycl opentyl)pyrimidin-2(1H)-one and 4-amino-1-((1S,3R,4R)-3-ethynyl-4-hydroxy-3-(hydroxymethyl)cyclopentyl)pyrimidin-2(1H)-one;

Isopropyl ((S)-(((1S,2S,4R)-4-(2-amino-6-ethoxy-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methoxy)(phenoxy)phosphoryl)-L-alaninate and Isopropyl ((S)-(((1R,2R,4S)-4-(2-amino-6-ethoxy-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methoxy)(phenoxy)phosphoryl)-L-alaninate;

Isopropyl ((S)-(((1S,2S,4R)-4-(2-amino-6-ethoxy-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methoxy)(phenoxy)phosphoryl)-L-alaninate or Isopropyl ((S)-(((1R,2R,4S)-4-(2-amino-6-ethoxy-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methoxy)(phenoxy)phosphoryl)-L-alaninate;

Isopropyl ((S)-(((1S,2S,4R)-4-(2-amino-6-ethoxy-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methoxy)(phenoxy)phosphoryl)-L-alaninate or Isopropyl ((S)-(((1R,2R,4S)-4-(2-amino-6-ethoxy-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methoxy)(phenoxy)phosphoryl)-L-alaninate;

((1S,2S,4R)-4-(6-chloro-2-fluoro-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate and ((1R,2R,4S)-4-(6-chloro-2-fluoro-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate;

((1S,2S,4R)-4-(6-amino-2-fluoro-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate and ((1R,2R,4S)-4-(6-amino-2-fluoro-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate;

((1S,2S,4R)-4-(2-amino-6-chloro-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate and ((1R,2R,4S)-4-(2-amino-6-chloro-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate;

((1S,2S,4R)-4-(2,6-dichloro-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate and ((1R,2R,4S)-4-(2,6-dichloro-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate;

((1S,2S,4R)-4-(6-amino-2-chloro-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate and ((1R,2R,4S)-4-(6-amino-2-chloro-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate;

((1S,2S,4R)-4-(6-amino-2-chloro-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate or ((1R,2R,4S)-4-(6-amino-2-chloro-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate;

((1S,2S,4R)-4-(2,4-dichloro-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate and ((1R,2R,4S)-4-(2,4-dichloro-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate;

((1S,2S,4R)-4-(4-amino-2-chloro-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate and ((1R,2R,4S)-4-(4-amino-2-chloro-7H-pyrrolo[2,3-d]pyrimidin-7-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate;

((1S,2S,4R)-4-(2-amino-6-oxo-1,6-dihydro-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate and ((1R,2R,4S)-4-(2-amino-6-oxo-1,6-dihydro-9H-purin-9-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate;

((1S,2S,4R)-1-ethynyl-2-hydroxy-4-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)cyclopentyl)methyl tetrahydrogen triphosphate and ((1R,2R,4S)-1-ethynyl-2-hydroxy-4-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)cyclopentyl)methyl tetrahydrogen triphosphate;

((1S,2S,4R)-4-(4-amino-2-oxopyrimidin-1(2H)-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate and ((1R,2R,4S)-4-(4-amino-2-oxopyrimidin-1(2H)-yl)-1-ethynyl-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate;

(1S,2S,4R)-4-(2-amino-6-oxo-1,6-dihydro-9H-purin-9-yl)-2-hydroxy-1-(hydroxymethyl)cyclopentane-1-carbonitrile and (1R,2R,4S)-4-(2-amino-6-oxo-1,6-dihydro-9H-purin-9-yl)-2-hydroxy-1-(hydroxymethyl)cyclopentane-1-carbonitrile;

(1S,2S,4R)-4-(4-amino-2-oxopyrimidin-1(2H)-yl)-2-hydroxy-1-(hydroxymethyl)cyclopentane-1-carbonitrile and (1R,2R,4S)-4-(4-amino-2-oxopyrimidin-1(2H)-yl)-2-hydroxy-1-(hydroxymethyl)cyclopentane-1-carbonitrile;

(1S,2S,4R)-2-hydroxy-1-(hydroxymethyl)-4-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)cyclopentane-1-carbonitrile and (1R,2R,4S)-2-hydroxy-1-(hydroxymethyl)-4-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)cyclopentane-1-carbonitrile;

(1S,2S,4R)-4-(6-amino-2-fluoro-9H-purin-9-yl)-2-hydroxy-1-(hydroxymethyl)cyclopentane-1-carbonitrile or (1R,2R,4S)-4-(6-amino-2-fluoro-9H-purin-9-yl)-2-hydroxy-1-(hydroxymethyl)cyclopentane-1-carbonitrile;

(1S,2S,4R)-4-(6-amino-2-fluoro-9H-purin-9-yl)-2-hydroxy-1-(hydroxymethyl)cyclopentane-1-carbonitrile or (1R,2R,4S)-4-(6-amino-2-fluoro-9H-purin-9-yl)-2-hydroxy-1-(hydroxymethyl)cyclopentane-1-carbonitrile;

((1S,2S,4R)-4-(2-amino-6-oxo-1,6-dihydro-9H-purin-9-yl)-1-cyano-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate and ((1R,2R,4S)-4-(2-amino-6-oxo-1,6-dihydro-9H-purin-9-yl)-1-cyano-2-hydroxycyclopentyl)methyl tetrahydrogen triphosphate; or

((1S,2S,4R)-1-cyano-2-hydroxy-4-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-y l)cyclopentyl)methyl tetrahydrogen triphosphate and ((1R,2R,4S)-1-cyano-2-hydroxy-4-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)cyclopentyl)methyl tetrahydrogen triphosphate;

or a pharmaceutically acceptable salt thereof.

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

5. A pharmaceutical composition comprising an effective amount of a compound of claim 1 , or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier and further comprising an effective amount of an anti-HIV agent selected from an anti-HIV antiviral agent, an immunomodulator, or anti-infective agent.

6. The pharmaceutical composition of claim 5 , wherein the anti-HIV antiviral agent is an HIV protease inhibitor, HIV reverse transcriptase inhibitor, HIV integrase inhibitor, HIV fusion inhibitor, HIV entry inhibitor, or HIV maturation inhibitor.

7. The pharmaceutical composition of claim 4 further comprising one or more additional HIV antiviral agents selected from:

abacavir, abacavir sulfate, abacavir+lamivudine, abacavir+lamivudine+zidovudine, amprenavir, atazanavir, atazanavir sulfate, AZT, capravirine, darunavir, dideoxycytidine, dideoxyinosine, delavirdine, delavirdine mesylate, dolutegravir, doravirine, efavirenz, 4′-ethynyl-2-fluoro-2′-deoxyadenosine, elvitegravir, emtricitabine, emivirine, enfuvirtide, etravirine, fosamprenavir calcium, indinavir, indinavir sulfate, lamivudine, lamivudine+zidovudine, lopinavir, lopinavir+ritonavir, maraviroc, nelfinavir, nelfinavir mesylate, nevirapine, PPL-100, raltegravir, rilpivirine, ritonavir, saquinavir, saquinavir mesylate, stavudine, tipranavir, or vicriviroc.

8. A method for the treatment of infection by HIV or for the treatment or delay in the onset of AIDS in a subject in need thereof, which comprises administering to the subject an effective amount of the compound of claim 1 , or a pharmaceutically acceptable salt thereof.