Synthesis of thiazolidinones from 1,4-dithiocyanatobut-2-enes and their use as masked 2-amino-1-mercaptobut-3-enes

Abstract

1,4-Dithiocyanatobut-2-enes can be readily prepared from either the appropriate buta-1,3-diene or 1,4-dihalogenobut-2-ene, and give, on heating in methanol, thiazolidinones via[3,3]-sigmatropic rearrangement. The initial products of this rearrangement, vicinal isothiocyanatothiocyanates, can be trapped with other nucleophiles: in benzene, amines react to afford dihydrothiazoles. The thiazolidinones are readily transformed to 2-amino-1-mercaptobut-3-enes, the corresponding carbamate esters and to the analogous disulphides. Reaction of these aminothiols with aldehydes and ketones, and with methyl bromoacetate afford respectively thiazolidines and thiomorpholinones.