4H-Pyrazolo[3,4-d]pyrimidin-4-one, 6-amino-3-bromo-1,5-dihydro-1-.beta.-D-ribofuranosyl- 6-Amino-3-bromo-1-.beta.-D-ribofuranosylpyrazolo[3,4-d]pyrimidin-4(5H)-one 96555-37-2 AIDS-001495 AIDS001495 Pyrazolopyrimidine nucleoside