First synthesis and further functionalization of 7-chloro-imidazo[2,1-b][1,3]thiazin-5-ones

Fused bicyclic 1,2,4‐triazoles with one extra sulfur atom: Synthesis, properties, and biological activity

“…Two different isomers are formed in equal amounts, depending on which nitrogen atom in the triazole cycle undergoes the cyclization (Scheme 25). [87] Condensation of equimolar amounts of triazoles and propiolic acid yields adducts identified as S-substituted acrylic acids in high yields (70%-80%). Physical and spectroscopic data of these compounds confirmed the formation of adducts.…”

A Four‐Component Domino Reaction: An Eco‐Compatible Access to Diversified Imidazo[2,1‐b][1,3]thiazin‐5‐ones

“…To date, the common synthetic methods to access imidazo [2,1-b] [1,3]thiazin-5-one scaffolds involve reactions between substituted phenylacryloyl chloride and 2-mercaptoimidazole; [4] bromopropionic acid with substituted imidazo[2,1-b]thiazol-3ones under acetic anhydride/acetic acid heated at reflux; [5] intramolecular cyclization of the respectivet hioacids in the presence of pyridine/acetic anhydride; [6] reactionso fa cryloyl chloride with 2-mercapto-benzimidazole; [7] reaction of isothiocyanate derivatives with corresponding amines; [3c, 8] and reaction of 2 H-pyran-2-ones with imidazolidin-2-thione. [9] The above methods suffer from the use of corrosiver eagents, poor yields, multistep syntheses, and harsh reactionc onditions.…”

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.…”