P-[[(4R,5R,7S,8R)-5-(3,4-Dihydro-2,4-dioxo-1(2H)-pyrimidinyl)-7-fluoro-8-hydroxy-6-oxa-1-thiaspiro[3.4]oct-7-yl]methyl] tetrahydrogen triphosphate

P-[[(4R,5R,7R,8R)-5-(4-Amino-2-oxo-1(2H)-pyrimidinyl)-8-hydroxy-6-oxa-1-thiaspiro[3.4]oct-7-yl]methyl] tetrahydrogen triphosphate

P-[[(4R,5R,7R,8R)-5-(3,4-Dihydro-2,4-dioxo-1(2H)-pyrimidinyl)-8-hydroxy-6-oxa-1-thiaspiro[3.4]oct-7-yl]methyl] tetrahydrogen triphosphate

(4R,5R,7R,8R)-5-(6-Amino-9H-purin-9-yl)-8-hydroxy-6-oxa-1-thiaspiro[3.4]octane-7-methanol

N-[9-[(4R,5R,7R,8R)-8-Hydroxy-7-(hydroxymethyl)-6-oxa-1-thiaspiro[3.4]oct-5-yl]-9H-purin-6-yl]-4-methoxybenzamide

N-[9-[(2′R,6aR,8R,9aR)-Dihydro-2,2,4,4-tetrakis(1-methylethyl)spiro[6H-furo[3,2-f]-1,3,5,2,4-trioxadisilocin-9(8H),2′-thietan]-8-yl]-9H-purin-6-yl]-4-methoxybenzamide

2-Amino-1,9-dihydro-9-[(4R,5R,7R,8R)-8-hydroxy-7-(hydroxymethyl)-6-oxa-1-thiaspiro[3.4]oct-5-yl]-6H-purin-6-one

2-Amino-9-[(2′R,6aR,8R,9aR)-dihydro-2,2,4,4-tetrakis(1-methylethyl)spiro[6H-furo[3,2-f]-1,3,5,2,4-trioxadisilocin-9(8H),2′-thietan]-8-yl]-1,9-dihydro-6H-purin-6-one

N-[9-[(2′R,6aR,8R,9aR)-Dihydro-2,2,4,4-tetrakis(1-methylethyl)spiro[6H-furo[3,2-f]-1,3,5,2,4-trioxadisilocin-9(8H),2′-thietan]-8-yl]-6,9-dihydro-6-oxo-1H-purin-2-yl]-2-methylpropanamide