N′-[1-[5-O-[Bis(4-methoxyphenyl)phenylmethyl]-3-O-[[bis(1-methylethyl)amino](2-cyanoethoxy)phosphino]-2-deoxy-β-D-erythro-pentofuranosyl]-4,5-dihydro-4-oxo-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidin-7-yl]-N,N-dibutylmethanimidamide

N′-[1-[5-O-[Bis(4-methoxyphenyl)phenylmethyl]-2-deoxy-β-D-erythro-pentofuranosyl]-4,5-dihydro-4-oxo-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidin-7-yl]-N,N-dibutylmethanimidamide

N,N-Dibutyl-N′-[1-(2-deoxy-β-D-erythro-pentofuranosyl)-4,5-dihydro-4-oxo-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidin-7-yl]methanimidamide

1-[5-O-[Bis(4-methoxyphenyl)phenylmethyl]-3-O-[[bis(1-methylethyl)amino](2-cyanoethoxy)phosphino]-2-deoxy-β-D-erythro-pentofuranosyl]-4-[[(dibutylamino)methylene]amino]-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidin-7-yl diphenylcarbamate

1-[5-O-[Bis(4-methoxyphenyl)phenylmethyl]-2-deoxy-β-D-erythro-pentofuranosyl]-4-[[(dibutylamino)methylene]amino]-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidin-7-yl N,N-diphenylcarbamate

Carbamic acid, diphenyl-, 1-(2-deoxy-β-D-erythro-pentofuranosyl)-4-[[(dibutylamino)methylene]amino]-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidin-7-yl ester

Carbamic acid, diphenyl-, 1-[2-deoxy-3,5-bis-O-[tris(1-methylethyl)silyl]-β-D-erythro-pentofuranosyl]-4-[[(dibutylamino)methylene]amino]-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidin-7-yl ester

1-[5-O-[Bis(4-methoxyphenyl)phenylmethyl]-3-O-[[bis(1-methylethyl)amino](2-cyanoethoxy)phosphino]-2-deoxy-β-D-erythro-pentofuranosyl]-6-(4-methoxybenzoyl)-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidine-4,7(5H,6H)-dione

1-[5-O-[Bis(4-methoxyphenyl)phenylmethyl]-2-deoxy-β-D-erythro-pentofuranosyl]-6-(4-methoxybenzoyl)-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidine-4,7(5H,6H)-dione

1-(2-Deoxy-β-D-erythro-pentofuranosyl)-6-(4-methoxybenzoyl)-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidine-4,7(5H,6H)-dione

1-[2-Deoxy-3,5-bis-O-[tris(1-methylethyl)silyl]-β-D-erythro-pentofuranosyl]-6-(4-methoxybenzoyl)-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidine-4,7(5H,6H)-dione

N-Benzoyl-N-[7-(benzoylamino)-1-[5-O-[bis(4-methoxyphenyl)phenylmethyl]-3-O-[[bis(1-methylethyl)amino](2-cyanoethoxy)phosphino]-2-deoxy-β-D-erythro-pentofuranosyl]-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidin-4-yl]benzamide

N-Benzoyl-N-[7-(benzoylamino)-1-[5-O-[bis(4-methoxyphenyl)phenylmethyl]-2-deoxy-β-D-erythro-pentofuranosyl]-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidin-4-yl]benzamide

N-Benzoyl-N-[7-(benzoylamino)-1-(2-deoxy-β-D-erythro-pentofuranosyl)-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidin-4-yl]benzamide

N-Benzoyl-N-[7-(benzoylamino)-1-[2-deoxy-3,5-bis-O-[tris(1-methylethyl)silyl]-β-D-erythro-pentofuranosyl]-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidin-4-yl]benzamide

1-[2-Deoxy-3,5-bis-O-[tris(1-methylethyl)silyl]-β-D-erythro-pentofuranosyl]-5-iodo-1H-imidazole-4-carbonitrile

1-[2-Deoxy-3,5-bis-O-[tris(1-methylethyl)silyl]-β-D-erythro-pentofuranosyl]-5-iodo-1H-imidazole-4-carboxamide

5-Amino-1-[2-deoxy-3,5-bis-O-[tris(1-methylethyl)silyl]-β-D-erythro-pentofuranosyl]-1H-imidazole-4-carbonitrile

Guanosine, 1′-(7-amino-4,5-dihydro-4-oxo-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidin-1-yl)-1′-de(6-amino-9H-purin-9-yl)-2′-deoxyadenylyl-(3′→5′)-2′-deoxycytidylyl-(3′→5′)-2′-deoxyguanylyl-(3′→5′)-2′-deoxycytidylyl-(3′→5′)-2′-deoxyguanylyl-(3′→5′)-2′-deoxycytidylyl-(3′→5′)-2′-deoxy-

Guanosine, 1′-(4-amino-5,7-dihydro-7-oxo-1H-imidazo[4′,5′:4,5]pyrido[2,3-d]pyrimidin-1-yl)-1′-de(6-amino-9H-purin-9-yl)-2′-deoxyadenylyl-(3′→5′)-2′-deoxycytidylyl-(3′→5′)-2′-deoxyguanylyl-(3′→5′)-2′-deoxycytidylyl-(3′→5′)-2′-deoxyguanylyl-(3′→5′)-2′-deoxycytidylyl-(3′→5′)-2′-deoxy-