Synthesis of 2- and 8-Cyanoadenosines and Their Derivatives : Nucleosides and Nucleotides. XXVII

A facile displacement of a methylsulfonyl group in adenosines with cyanide ion is described. Treatment of protected 8-methylsulfonyladenosines with sodium cyanide in dimethylformamide gave the 8-cyanoadenosines. The conversion of the cyano group to the methyl imidate, methoxycarbonyl, carbamoyl, and carboxylic acid, respectively, was achieved. Similar reaction was carried out with 2-methylsulfonyladenosines to give the 2-cyanoadenosines and their derivatives. The nuclear magnetic resonance (NMR) and circular dichroism (CD) spectra of these 2-and 8-substituted adenosines are given. The 8-substituted adenosines possess syn-conformations while the 2-substituted derivatives prefer to possess anti-conformations, as confirmed by the CD and NMR spectra.