Facile Synthesis and Crystal Structure of <i>N</i>-(3-Cyano-4,5,6,7-tetrahydrobenzo[<i>b</i>]thiophen-2-yl)-2,2,2-trifluoroacetamide

Abstract

N-(3-Cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-2,2,2-trifluoroacetamide was synthesized by the acylation reaction of trifluoroacetic anhydride with 2-amino-4,5,6,7-tetrahydro-benzo[b]thiophene-3-carbonitrile, which was prepared via microwave-assisted Gewald reaction with K2CO3 as a heterogeneous solid base catalyst. This protocol presented such advantages as short reaction time, high yield, easy work-up and environmentally benign procedures. The structure of the title compound was confirmed by IR, 1H NMR, MS, elemental analysis and X-ray single-crystal diffraction method. X-Ray diffraction analysis reveals that the cyclohexene ring adopts a half-chair conformation and the thiophene ring is essentially planar.