CYCLOCONDENSATION OF NOVEL THIAZOLO[3,2-A]BENZIMIDAZOLES

3-Aminothiazolo[3,2-a]benzimidazole-2-carboxamide (2) was synthesized and cyclized with aliphatic and aromatic acids or with their chlorides to give compounds 3a, and 3b respectively Thiazolo[3,2-a] benzimidazole 1 was cyclized to oxazine-4 which reacted with NH4OH, hydrazinehydrate, ethyl amine and methyl amine hydrochloride to give the corresponding 3a, 5, and 6. Cyclocondensation of 1 with phenylacetic acid gave the cyclized product 7, while the reaction of 1 with o-phenylenediamine in acidic medium afforded 8.