Reaction of heterocyclic thioamides with dimethyl acetylenedicarboxylate. Synthesis of novel 2-azolyl-5-methoxycarbonylmethylene thiazolin-4-ones

A systematic study of the reactions of dimethyl acetylenedicarboxylate (DMAD) with heterocyclic thioamides has been carried out and a number of new 2-isoxazolyl-(8), imidazolyl-(13a,b and 17a), 1,2,3-triazolyl-(13d,e) and 1,2,3-thiadiazolyl (17b) thiazolines have been prepared. The higher reactivity of the thioamide group in comparison with the amino group in these reactions has been established. (C) 2001 Elsevier Science Ltd. All rights reserved.