Purines, pyrimidines, and imidazoles. Part XXXII. Synthesis of 5-amino-4-cyano-1-β-D-ribofuranosylimidazole-5′-phosphate and a new mild method for dehydration of carboxamides to nitriles

Abstract

The major product obtained by phosphorylation of 5-amino-1-(2,3-O-isopropylidene-β-D-ribofuranosyl)imidazole-4-carboxamide (IIb) with pyrophosphoryl chloride and removal of the protecting group was 5-amino-4-cyano-1-β-D-ribofuranosylimidazole-5′-phosphate. The mild dehydration is general and has been extended to include simple similar carboxamides. The mechanism of the process and a related reaction are discussed. 5-Amino-4-cyano-1-cyclohexylimidazole has also been prepared from aminomalononitrile by the Shaw aminoimidazole synthesis.