Activated Nitriles in Heterocyclic:Synthesis Novel Syntheses of Imidazo[2,1-b]-1,3-Thiazine Derivatives

Synthesis of Novel Derivatives of (Benz)Imidazo[2,1-b]Pyrimido[4,5-d][1,3]Thiazine

“…Some medicinal properties of imidazothiazine derivatives consist of anticancer, anti-leukemia, antifungal, anti-inflammatory and antisecretory activities. [16][17][18][19] There are various methods reported for the synthesis of imidazothiazines, including the reaction of 5,5-diphenyl-2-thiohydantoin with α,β-unsaturated nitriles, 20 cyclisation of 5,5-diphenyl-2-thiohydantoins with 1,3-dibromopropane under phase-transfer catalysis conditions, 21 the reaction of 3,3-dichloro-2-phenylacryloyl chloride with mercaptoimidazoles, 22 one-step reaction of benzimidazoline-2-thione with cinnamoyl chloride 23 and cyclisation of benzimidazolethiones with ethyl 3-chloro-but-2-enoate. 24 Considering the pharmacological and biological activities of pyrimidothiazines and imidazothiazines and as part of our ongoing studies dealing with the synthesis of various fused pyrimidines, [25][26][27][28][29][30][31] we describe here a facile synthesis and structural elucidation of 2-substituted-imidazo-and benzimidazo-[2,1-b]pyrimido [4,5-d] [1,3]thiazines 8a-e and 9a-e as novel heterocyclic systems that may be good candidates in designing new biologically active compounds.…”