Fused thia-heterocycles via isothiocyanates. Part I. Facile synthesis of some new 1-benzothiopyran-4-one derivatives

摘要

A selected set of new 4H-benzothiopyran-4-one derivatives 6a-h has been prepared by a one-pot reaction involving deprotonated methyl 3-oxo-3(2 ', 4 ', 5 '-trichlorophenyl)propanoate 5 and the appropriate aryl or alkyl isothiocyanate. 2,4,5-Trichloroacetophenone 4, required for the synthesis of 5, is successfully prepared by Friedel-Craft's acetylation of 1,2,4-trichlorobenzene in 82% yield. The structures of the new compounds 5 and 6a-h are based on microanalytical and spectral (NMR, MS(EI), and HRMS) data.