Synthesis of sulfanylidene-diazaspirocycloalkanones in a three-component Mannich-type reaction catalyzed with lactic acid

Abstract

The aminomethylation of thioamides containing an acidic hydrogen atom at the α-carbon atom was investigated as a general reaction. Spirohexahydropyrimidines were obtained in the one-pot, three-component reaction of a variety of cyclic-ketone-derived thioamides, primary amines and formaldehyde with lactic acid acting as a catalyst. The results of our experiments confirmed the high catalytic efficiency of lactic acid. A proper choice of the starting thioamides and amines makes it possible to use this reaction methodolgy to synthesize several new and potentially useful derivatives of hexahydropyrimidine, e.g., biologically-active compounds.