A convenient synthesis of 6-amino-1-β-D-ribofuranosylpyrazolo[3,4-d] pyrimidin-4-one and related 4,6-disubstltuted pyrazodopyrimidine nucleosldes

Abstract

The glycosylation of 4,6-dichloropyTazolo[3,4-d]pyrinidine and 4-chloro-6-nethylthiopyrazolo[3,4-d]pyrimidine via the corresponding trlmethylsilyl intermediate and tetra-O-acetyl-β-D-rlbofuranose in the presence of trinethyl-silyl trlflate as a catalyst, gave selective glycosylation at N1 as the only nucleoslde product. The intermediates 4,6-dichloro-l-(2,3,5-tri-(acetyl-β-D-ribofuranosyl)pyraEolo[3,4-d]pyripidine 7 and 4-chloro-6-methylthio-l-(2,3,5-tri-(acetyl-β-D-rlbofurano8yl)pyTarolo[3,4-d]pyrimidine 13 gave new and convenient synthetic routes to the inosine analog 1 the guanosine analog 2, the adenosine analog 3, and the isoguanosine analog 16. Glycosylation of the tri-methylsilyl derivative of 6-chloropyraEolo[3,4-d]pyTimidin-4-one unexpectedly gave the N2-glycosyl lsomer 20 as the major product. A number of new 4,6-disubstituted pyrarolo[3,4-d]pyrimidine nucleosides were prepared from these glycosyl intermediates. © 1983 IRL Press Limited.