2-amino-9-[(2R,3R,4S,5R)-5-({[(R)-{[(R)-{[(S)-({(2R,3R,4R,5R)-3-{[(R)-{[(2R,3R,4R,5R)-3-{[(S)-{[(2R,3R,4R,5R)-5-(4-amino-2-oxopyrimidin-1(2H)-yl)-3-{[(S)-hydroxy{[(2R,3R,4R,5R)-3-hydroxy-4-methoxy-5-(3-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)tetrahydrofuran-2-yl]methoxy}phosphoryl]oxy}-4-methoxytetrahydrofuran-2-yl]methoxy}(hydroxy)phosphoryl]oxy}-5-(6-amino-9H-purin-9-yl)-4-methoxytetrahydrofuran-2-yl]methoxy}(hydroxy)phosphoryl]oxy}-5-[6-(dimethylamino)-9H-purin-9-yl]-4-methoxytetrahydrofuran-2-yl}methoxy)(hydroxy)phosphoryl]oxy}(hydroxy)phosphoryl]oxy}(hydroxy)phosphoryl]oxy}methyl)-3,4-dihydroxytetrahydrofuran-2-yl]-7-methyl-6-oxo-6,9-dihydro-3H-purin-7-ium