Facile one-pot synthesis of thiazol-2(3H)-imine derivatives from α-active methylene ketones.

A facile and efficient One-pot procedure was achieved for the synthesis of thiazol-2(3H)-imine derivatives through the bromination of some α-active methylene ketones followed by treatment with potassium thiocyanate and condensation with various primary amines in ethanol as one-pot four-step process. The α-active methylene ketones were symmetrical and asymmetrical ketones. The primary amines used were mostly aromatic amines and also benzylamine was used. This proposed method does not require the use of techniques such as extraction and chromatography. Surprisingly, the product from the reaction of 3-thiocyanacetylacetone and benzylamine was elucidated to be N-(3-benzyl-4-hydroxy-4-methylthiazolidin-2-ylidene)acetamide (2) and not the expected compound 1-(3-benzyl-2-imino-4-methyl-2,3-dihydrothiazol-5-yl)ethan-1-one (1),which was proved based on the existence of the methylene and hydroxyl group in the compound.The mechanism of the novel compound 2 was confirmed by subsequent chemical reactions, spectroscopic data and X-ray crystallography.The molecular structure of all newly synthesized thiazol-2(3H)-imine derivatives were elucidated on the basis of spectroscopic dataand elemental analysis.