Synthesis of substituted thieno[2,3-d]thiazoles and indolo[3,2-d]thiazoles

Alkylene-, halo-, and aryl-substituted 2-methylthieno(2,3-d)thiazoles were obtained by the action of phosphorus pentasulfide on the corresponding 2-acetylamino-3-bromo- or 2-acetylamino-3-hydroxythiophenes in an organic solvent with heating. 2-Oximes of halo- and methyl-substituted isatins were converted by reduction and acylation into 2-hydroxy-3-acetylaminoindoles, from which 2-methylindolo(3,2-d)-thiazoles were obtained by the action of phosphorus pentasulfide with heating in xylene. Results of electron impact ionization behavior, spin-spin coupling constant analysis, and mass and NMR structural determinations are given. A quantum-chemical atomic model is constructed for the thiazoles.