An environmentally Benign Synthesis of 2-Cyanomethyl-4-Phenylthiazoles under FocusedMicrowave Irradiation

Abstract

An improved environmentally benign procedure for synthesis of substituted 2-cyanomethyl-4-phenylthia- zoles under focused microwave irradiation using glycerol as solvent has been carried out. The method allows the synthesis of products in excellent yields with short reaction times and the work-up is easy. This approach can be applied to the preparation of a variety of derivatives

Glycerol: a solvent and a building block of choice for microwave and ultrasound irradiation procedures

“…Interest in the synthesis of 2-thiazolyl-substituted pyrroles has increased recently because of the discovery of highly efficient enzyme inhibitors among 2-thiazolylpyrroles derivatives. Deligeorgiev et al () 8 have described an improved and environmentally benign procedure for the synthesis of substituted 2-cyanomethyl-4-phenylthiazoles from a number of Journal Name ARTICLE Scheme 4 substituted 2-bromoacetophenones under MW irradiation using glycerol as the solvent (Scheme 5). The fast procedure (around 4 min) gave excellent yields and high purity products after a simple work-up.…”

Synthesis and Anticancer Evaluation of Some Novel Thiophene, Thieno[3,2‐d]pyrimidine, Thieno[3,2‐b]pyridine, and Thieno[3,2‐e][1,4]oxazepine Derivatives Containing Benzothiazole Moiety

“…Biologically active thienopyrimidinone derivatives can be also established from reaction of 2‐aminoesters with different thiocyanates or activated nitriles . Consequently, compound 14 reacted with ammonium thiocyanate to give the corresponding thienopyrimidinone derivative 21 , while nucleophilic addition of amino group in compound 14 on cyano function in 2‐(4‐(4‐chlorophenyl)thiazol‐2‐yl)acetonitrile 22 followed by intramolecular cyclization with removal of ethanol molecule yielded the corresponding thienopyrimidinone analogue 23 . Moreover, multicomponent reaction of 2‐aminoesters with mixture of substituted amines and triethyl orthoformate produced the corresponding thienopyrimidinone derivatives .…”

“…A mixture of compound 14 (0.34 g, 1 mmol) and compound 22 (0.47 g, 2 mmol) in glacial acetic acid (10 mL) was heated under reflux for 8 h, where upon reddish brown powder was formed. The obtained product was filtered, dried, and crystallized from toluene.…”

Recent Advances in the Use of Glycerol as Green Solvent for Synthetic Organic Chemistry

“…Once again, after extraction of the final reaction products with ethyl acetate, glycerol could be used for further reactions without any problem. In an independent report, an effective synthesis of related 2-cyanomethyl-4-phenylthiazoles 11 from different substituted 2-bromoacetophenones and 2-cyanothioacetamide was also described (Scheme 9) [54]. Reactions, which were in this case performed under MW conditions, delivered the desired products with high purity and yields after very short irradiation periods (3-4.5 min).…”