Synthetic access to imidazo[2,1-b]thiazoles

Regioselective reaction of imidazole-2-thiols with N-sulfonylphenyldichloroacetaldimines: en route to novel sulfonylamino-substituted imidazo[2,1-b]thiazoles and thiazolo[3,2-a]benzimidazoles

“…The advantages of the method for the preparation of the imidazothiazole and thiazolobenzimidazole derivatives are available starting reagents, catalyst-free one-step procedure, and high selectivity. The known methods 19,[21][22][23][24] have never been used for the preparation of sulfonylaminosubstituted derivatives containing synthetically useful and pharmacophoric sulfonamide groups. It can be argued that the method proposed herein complements the known literature protocols and expands the scope of functionalized imidazothiazoles derivatives which are now available for further investigation of biological activity and other properties.…”

“…19 3-Alkyl-thiazolo [3,2-a]benzimidazole derivatives were also obtained from 1,2-diaminobenzene, CS2, and haloketones via the intermediated 4-alkyl-N-3-(2-aminophenyl)-thiazoline-2-thiones. 20 Very promising are multi-component syntheses of aminosubstituted imidazo [2,1-b]thiazoles from 2-aminothiazoles, isocyanides and aldehydes or bromoacetophenones, aromatic aldehydes, thiourea and isocyanides.…”

“…20 Very promising are multi-component syntheses of aminosubstituted imidazo [2,1-b]thiazoles from 2-aminothiazoles, isocyanides and aldehydes or bromoacetophenones, aromatic aldehydes, thiourea and isocyanides. 19,21 Thiazolobenzimidazoles bearing the imidazo [2,1-b]thiazole fragment were obtained by the reaction of benzimidazole-2-thiol with bromomalononitrile. 11,[22][23][24] We are engaged in elaboration of approaches to the preparation of annulated imidazole derivatives containing synthetically important pharmacophoric sulfonylamino group.…”

Ultrasound for Drug Synthesis: A Green Approach

“…Tetrazolo[1,5-a]quinolines and imidazo[2,1-b]thiazoles are important molecules that exhibit a wide variety of biological activities and have potential uses as antidiabetics [100], antifungals [101], and antibiotics [102], and against age-related diseases [103]. Tetrazolo[1,5-a]quinolones [104] and imidazo[2,1-b]thiazoles [101,105] are traditionally synthesized under harsh conditions requiring toxic chemicals, high temperatures, or expensive catalysts, and have a limited substrate scope. In 2018, Claudio-Catalań et al [106] developed a sono-assisted, solvent-and catalyst-free, one-pot green synthesis of bis-heterocycles containing imidazo[2,1-b]thiazole or benzo[d]imidazo[2,1-b]thiazole.…”

One-pot regioselective synthesis of new 5-(arylsulfonylamino)imidazo[2,1-b]thiazoles

“…The most efficient method to obtain imidazo [2,1-b]thiazoles is the conversion of 2-aminothiazole with α-halocarbonyl compounds or propargylbromide (Scheme 2). 28 Imidazo[2,1-b]thiazoles can also be prepared via the reaction of α-halocarbonyl compounds with 2-mercaptoimidazoles. 28 The most promising approach to amino-substituted imidazo [2,1-b]thiazoles is based on multicomponent reactions of 2-aminothiazole, isocyanides, and aldehydes or 2-bromoacetophenone derivatives, aromatic aldehydes, thiourea, and isocyanides (Scheme 2).…”