Synthesis of indole, benzofuran and benzothiophene by reaction of 2-anilinoethanol, 2-phenoxyethanol and 2-(phenylthio)ethanol on AlPO 4 and Pd/AlPO 4 catalysts

Abstract

The synthesis of indole, benzofuran and benzothiophene is possible from compounds of the general formula: X-CH 2CH 2OH (X = NH, O, S). The reaction of 2-anilinoethanol, 2-phenoxyethanol and 2-(phenylthio)ethanol on aluminium orthophosphate and palladium supported by aluminium orthophosphate catalysts was studied. The synthesis of benzothiophene over AlPO 4 was optimized by the response surface methodology. A possible mechanistic pathway involving an acid media cyclization is discussed.