SYNTHESIS AND REACTIONS OF HETEROCYCLIC SYSTEMS CONTAINING CINNOLINE MOIETY

Abstract

The object of the present work is the synthesis of some new heterocyclic systems containing the pyrido [3,2-c] cinnoline moiety fused with other heterocyclic systems, namely; thiophene, pyrazole thienopyrimidine, triazolothienopyrimidine, tetrazolothienopyrimidine and other cinnoline derivatives.

This was achieved VIa the key compound 3-cyano-4-(p-tolyl)­ pyrido[3,2-c]cinnoline-2(1H)-one (II) which was synthesised by the interaction of 4-amino-3-(p-methylbenzoyl)cinnoline (I) with ethyl cyanoacetate and ammonium acetate. When compound (II) was reacted with phosphorus pentasulphide in pyridine, it gave 3-cyano-4-(p-tolyl) pyrido[3,2-c]cinnolin-2(1H)-thione (IV).

Alternatively, compound (IV) was prepared from interaction of compound (II) with phosphorus oxychloride to give the chloro compound (ill) which in turn reacted with thiourea followed by hydrolysis with sodium hydroxide and . then acidified with hydrochloric acid to give compound (IV).