1H-Pyrazolo(3,4-d)pyrimidine, 4-(((4-nitrophenyl)methyl)thio)-1-beta-D-ribofuranosyl- 64372-71-0 7-((4-Nitrobenzyl)thio)-3-(beta-D-ribofuranosyl)pyrazolo(4,3-d)pyrimidine 7-Nbtf Nitrobenzylthioformycin