High-yield regioselective synthesis of 9-glycosyl guanine nucleosides and analogues via coupling with 2-<i>N</i>-acetyl-6-<i>O</i>-diphenylcarbamoylguanine

Abstract

Treatment of 2-N,9-diacetylguanine with diphenylcarbamoyl chloride followed by heating with aqueous ethanol gave 2-N-acetyl-6-O-diphenylcarbamoylguanine (2-acetamido-6-diphenylcarbamoyloxypurine). Bis-trimethylsilylation of this product followed by coupling with glycosyl acetates (trimethylsilyl triflate catalysis) or α-haloethers in anhydroustoluene gave 9-substituted guanine compounds in high yields with no 7-isomers detected.