Synthesis of 6-cyano and 6-unsubstituted 2-aryl-8-oxopurine from a common 2-oxoimidazole precursor

Abstract

The benzyl urea of diaminomaleonitrile, prepared from commercially available starting materials, was reacted with aromatic aldehydes at room temperature. Intramolecular cyclization of the product, in basic solution, generated a substituted 2-oxoimidazole. This compound proved to be a common precursor for 2-aryl-6-cyano-8-oxopurines upon treatment with acid and for 2-aryl-6-unsubstituted-8-oxopurines, in the presence of base. A 1H NMR study of these simple and versatile reactions supports the mechanistic proposal. © 2010 Elsevier Ltd. All rights reserved.