Synthesis and antimicrobial activity of 1,3,5-thiadiazines and their isomerism into 1,3,5-triazines

Abstract

A series of 2,6-diphenylimino-4-(substituted)-benzylidene amino-1,3,5-thiadiazines <b style="">4a-g</b> have been obtained by the basification of their hydrochlorides <b style="">3a-g</b>, which are prepared by interaction of <i style="">N</i>-phenyl isocyanodichloride and 1-(substituted)- benzylidene amidino-3-phenyl thiocarbamides <b style="">2a-g</b>. The latter have been synthesized by the condensation of 1-amidino-3-phenyl thiocarbamide <b style="">1</b> and different aliphatic and aromatic aldehydes. Compounds <b style="">4a-g</b> on acylation afford monoacetyl derivatives <b style="">5a-g</b>, on reaction with sodium nitrite in acidic medium afforded mononitroso derivatives <b style="">6a-g</b>, and on boiling with 5% aqueous ethanolic (1:1) sodium hydroxide solution isomerize into corresponding 1-phenyl-2-phenylimino-4-(substituted)-benzyl­idene amino-6-thio-1,3,5-triazines <b style="">7a-g</b>. The title compounds have been assayed for their antimicrobial activity against gram-positive as well as gram-negative microorganisms.