Synthesis of 2-(Aminomethylene)-2H,3H-1-benzothiophene-3-one from 3-Bromo-4H-1-benzothiopyran-4-one as a New Donor–acceptor Chromophore

Abstract 2-(Amino-substituted methylene)-2H,3H-1-benzothiophene-3-ones were prepared by ring contraction of 3-bromo-4H-1-benzothiopyran-4-one with amines, as a new donor–acceptor chromophore. The structure of 2-(N,N-dimethylaminomethylene) derivative was determined by X-ray crystallographic analysis.