Multistep synthesis of thiazoloquinazolines under microwave irradiation insolution

Thiazolo[5,4-f]quinazolines are synthesised in six or seven steps from 2-am ino-5-nitrobenzonitrile. Both heterocyclic rings are fused onto the central benzene ring via imino-1,2,3-dithiazoles which are readily obtained from p rimary aromatic amines and 4,5-dichloro-1,2,3-dithiazolium chloride (Appel salt). Four of the steps were improved in yield or reaction time or both, c ompared to conventional heating, by microwave irradiation of solutions of t he reactants in a focused open microwave oven. (C) 2000 Elsevier Science Lt d. All rights reserved.