Smart cleavage reactions: the synthesis of benzimidazoles and benzothiazoles from polymer-bound esters

Synthesis and mutagenicity of 2-aryl-substitute (o-hydroxy-, m-bromo-, o-methoxy-, o-nitro-phenyl or 4-pyridyl) benzothiazole derivatives on Salmonella typhimurium and human lymphocytes exposed in vitro

“…Except for one of the synthesized compounds, 2-(mbromo-phenyl)-benzothiazole (BT-12), all the compounds were reported on in the literature (Hides & Hankovsky 1963;Isikdag & Ucucu 1990;Jung et al 2000;Ikegami & Arai 2002;Ulrich 2002;Chakraborti et al 2004;He et al 2004;Kodomari et al 2004;Matsushita et al 2004). BT-12 was the compound synthesized originally within this study.…”

Ammonium chloride; as a mild and efficient catalyst for the synthesis of some 2-arylbenzothiazoles and bisbenzothiazole derivatives

“…In general, benzothiazoles are synthesized by condensation of 2-aminothiophenol with carboxylic acid derivatives [4], onepot reaction of 2-aminothiophenol with β-chlorocinam aldehydes using pTsOH [5], condensation of 2-aminothio phenol with acid chlorides [6], esters [7], arylation of benzothiazoles with aryl bromides at 150 o C in a sealed tube catalyzed by Pd(OAc)2, Cs2CO3, and CuBr with P(t-Bu)3 as ligand [8], multistep synthetic approaches of 2-arylbenzo thiazoles [9] or Suzuki biaryl coupling of 2-arylbenzothiazoles with aryl boronic acid [10].…”

Solid-Phase Synthesis of 2-Arylbenzothiazole Using Silica Sulfuric Acid under Microwave Irradiation

“…5,6 In general, benzothiazoles are synthesized by condensation of 2-aminothiophenol with carboxylic acid derivatives, 7 the base induced cyclization of the corresponding 2 haloanilides, 8 or the radical cyclization of thioacylbenzanilides. 9 On the other hand, the most general synthetic approaches for 2-aryl benzothiazoles involves: (i) arylation of benzothiazole with aryl bromides at 150 ο C in a sealed tube catalyzed by Pd(OAc)2, Cs2CO3 and CuBr with t-Bu 3 P as ligand, 10 or Suzuki biaryl-coupling of 2-bromobenzothiazole with aryl boronic acids, 11 (ii) oxidative cyclisation of phenolic Schiff's bases derived from the condensation of 2-aminothiophenols and aldehydes using various oxidants such as Sc(OTf)3 using molecular oxygen, 12 pyridinium chlorochromate 13 and very recently via electrooxidation, 14 a modification of such strategy that involves flash vacuum pyrolysis and photolysis of 2-methylthio-N (arenylidene)anilines has been reported, 15 (iii) condensation of 2-aminothiophenols with carboxylic acids under microwave irradiation 16 or with polymer-bound esters in the presence of a Lewis acid, 17 (iv) direct condensation of 2-aminothiophenol with aromatic aldehydes, 18,19 under microwave-irradiation. [20][21][22] However, most of these synthetic approaches suffer from drawbacks such as harsh reaction conditions, lengthy procedures, expensive catalysts which may be harmful to the environment.…”