A novel multicomponent synthesis of polyfunctionalized bicyclic tetrahydropyrimidinone derivatives via mercaptoacetylative ring transformations.

A novel K-10 clay (nanoclay)-catalyzed expeditious synthesis of polyfunctionalized bicyclic pyrimidines using unprotected aldoses, 2-methyl-2-phenyl-1,3-oxathiolan-5-one and amidines/guanidine is reported. These polyfunctionalized bicyclic pyrimidines were obtained in excellent yields (72-93%) with high cis diastereoselectivity (>94%) at the ring junction via tandem condensation, mercaptoacetylative ring transformation and cyclization reactions. The process presents an excellent illustration of use of carbohydrates as renewable resources for the formation of pharmaceutically relevant fine chemicals employing solvent-free microwave irradiation conditions in a one-pot procedure.