One-Pot Syntheses of Substituted 2-Aminothiazoles and 2-Aminoselenazoles via Meerwein Arylation of Alkyl Vinyl Ketones

Abstract

AbstractBoth one-pot and two-step procedures for the synthesis of substituted 2-aminothiazoles and 2-aminoselenazoles are described. Anilines are first converted into arenediazonium bromides, which are then reacted with methyl vinyl ketone or cyclopropyl vinyl ketone in the presence of copper(II) bromide to give 4-aryl-3-bromobutan-2-ones (40–71%) and 3-aryl-2-bromo-1-cyclopropylpropan-1-ones (41–79%), respectively. These products are reacted, without prior isolation, with thiourea or selenourea to prepare 4-methyl- and 4-cyclopropyl-5-(R-benzyl)thiazol-2-amines (14 examples) and their selenium analogs (14 examples). The yields of the one-pot procedure are higher (40–81%) than those of the two-step procedure (32–70%).