ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Reactivity of Esters and Nitriles of 2-(3-Acylthioureido)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylic Acids 1. Acid-Catalyzed Cyclization and Desulfanation Reaction in the Presence of Secondary Amines

P. Pazdera and I. Preissová

Department of Organic Chemistry, Faculty of Natural Sciences, Masaryk University, CS-611 37 Brno

Abstract: Esters and nitriles of 2-(3-acylthioureido)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylic acids were cyclized in a solution of concentrated sulfuric acid at room temperature to substituted thieno[2,3-d]-[1,3]-thiazines. Further they were treated with mercuric oxide (desulfanation reaction) in the presence of secondary amines (diethylamine, morpholine, piperidine) forming corresponding 1-acylguanidines in some cases accompanied by the cyclization to thieno[2,3-d]-pyrimidines. These were also prepared by the cyclization of 1-acylguanidines in concentrated sulfuric acid at room temperature.

Full paper in Portable Document Format: 466a396.pdf

Chemical Papers 46 (6) 396–405 (1992)