New One Pot and Efficient Four‐Components Reaction for Synthesis of 2,3‐Dihydrothiophene Carbamate Derivatives

A new series of 2,3‐dihydrothiophenes bearing ethyl carbamate moiety (4 a–4 l) was designed and synthesized through a facile synthetic route involving domino ring‐opening/recyclization reaction of 1,3‐thiazolidinedione. The synthesis was achieved via a novel one‐pot four‐component reaction of aromatic aldehydes, malononitrile and 1,3‐thiazolidinedione, using 4‐dimethylaminopyridine as base catalyst under ethanol reflux. The molecular structures of the synthesized compounds were elucidated by usual spectroscopic techniques such as FT‐IR, 1H NMR, 13C NMR and HRMS methods. X‐ray diffraction was used to confirm the structures of compounds 4 d and 4 j. Readily available starting materials, atom‐efficient routes employing more mild reaction conditions and environmentally benign are the attracting features of this current protocol. A new series of 2,3‐dihydrothiophene carbamate derivatives was prepared by a novel four‐component reaction between a variety of aromatic aldehydes, malononitrile, 1,3‐thiazolidinedione at reflux in ethanol which acts as solvent and nucleophile, in the presence of N,N‐dimethylaminopyridine as base.