Abstract

Given the broad spectrum of uses of acrylonitrile derivatives as fluorescent probes, AChE inhibitors, and others, it is necessary to find easy, efficient and simple methods to synthesize and diversify these compounds. We report the results of a comparative study of the effects of three techniques on the reactions between heterocyclic aldehydes and 2-(benzo[d]thiazol-2-ypacetonitrile: stirring; ultrasound coupled to PTC conditions (US-PTC); and MW irradiation (MWI) under solvent and catalyst-free conditions. The effects of conditions on reaction parameters were evaluated and compared in terms of reaction time, yield, purity and outcomes. The US-FTC method is more efficient than the MWI and conventional methods. The reaction times were considerably shorter, with high yields (>90%) and good levels of purity. In addition, X-ray diffraction analysis and quantum mechanical calculations, at the level of density functional theory (DFT), ratify obtaining acrylonitrile isomers with E configurations. The crystal structure of 3c is stabilized by weak C-H-o center dot center dot center dot N intermolecular interactions (H-o center dot center dot center dot NC = 2.45 angstrom, C-o center dot center dot center dot NC = 3.348(3) angstrom, H-o center dot center dot center dot NC = 162 degrees), forming centrosymmetric ring R-2(2) (20) along the crystallographic a axis. (C) 2014 Elsevier B.V. All rights reserved.