Analogs of AICA- and IsoAICA Ribosides and Their Methylated Base Counterparts

Abstract

A mild, convenient and efficient synthesis has been developed for imidazole-4-thiocarboxamide and imidazole-5-thiocarboxamide ribosides and the analogous selenocarboxamides. This methodology, i.e., DMF saturated with H₂S or H₂Se, also converts the corresponding N-methylated bases to the corresponding amides. The imidazole-4(5)-selenocarboxamides were shown to be sensitive to base (pH 11) and were easily converted back to their cyano precursors. The kinetics of these reactions were determined and they indicate that the C5 amides were more reactive than their C4 analogs.