Thiourea as a Precursor to Sophisticated Heterobicyclic Compounds by a Double Annulation Reaction

Abstract

Abstract We report here the first example of an efficient regioselective synthesis of heterobicyclic compounds using thiourea as starting material. The key step in this synthetic process is the preparation of N , N′ ‐bis[(dimethylamino)methylene]thiourea ( 1 ), which reacts as thiazadiene, leading to diazadiene heterocycles. These heterocycles give either thiazolopyrimidine 4 or imidazo‐1,3‐thiazine 7 by a double annulation reaction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)