The chemistry of o-phenylene di-isothiocyanate. Part 2. Reactions with enamines, an ynamine, and some reactive methylene compounds

Abstract

Reactions of o-phenylene di-isothiocyanate with activated methylene compounds have given, with acetylacetone and benzoylacetone, 1-substituted thiocarbonyl benzimidazoline-2-thiones and with malononitrile and ethyl cyanoacetate 3,4-dihydro-2H-benz[d]imidazol[2,1-b][1,3]thiazines. Enamines, as exemplified by 1-pyrrolidin-1-ylcyclohexene, react with the di-isothiocyanate and give benzimidazo[2,1-b][1,3]benzothiazine-11-thiones or substituted thiocarbonyl benzimidazoline-2-thiones. An ynamine, 1-diethylaminoprop-1-yne, reacted with o-phenylene di-isothiocyanate to give 2-diethylamino-3-methylbenzimidazo[2,1-b][1,3]thiazine-4-thione.