Preparation of benzothiopyrano2,3-bIndoles by the reaction of l,3-dihydroindole-2-thiones with certain dienophiles

摘要

Benzothiopyrano2,3-bindoles were prepared by the cyclization of l,3-dihydroindole-2-thiones with various dienophiles. The l,3-dihydroindole-2-thiones were readily synthesized by the reaction of oxindole with P_2S_5 followed by a piperidine-mediated condensation of the resulting thioindole with a suitable aromatic aldehyde.