[(2R,3S,5R)-5-(6-aminopurin-9-yl)-3-hydroxyoxolan-2-yl]methyl phosphate [(2R,3S,5R)-5-(6-aminopurin-9-yl)-3-hydroxy-tetrahydrofuran-2-yl]methyl phosphate [(2R,3S,5R)-5-(6-amino-9-purinyl)-3-hydroxy-2-tetrahydrofuranyl]methyl phosphate [(2R,3S,5R)-5-(6-aminopurin-9-yl)-3-hydroxy-oxolan-2-yl]methyl phosphate