One-Pot Synthesis of 3-Acyl-2-(alkylsulfanyl)indoles and 2-(Alkylsulfanyl)-indole-3-carboxylates from (2-Isocyanophenyl)methyl Ketones or (2-Isocyanophenyl)acetates

摘要

An efficient method has been developed for the preparation of 3-acyl-2-(alkylsulfanyl)indoles and ethyl 2-(alkylsulfa-nyl)indole-3-carboxylates under mild conditions. (2-Iso-cyanophenyl)methyl ketones and ethyl 2-(2-isocyanophenyl)ace-tates were converted into the corresponding isothiocyanates by treatment with sulfur in the presence of a catalytic amount of selenium. The isothiocyanates were then treated with two equivalents of sodium hydride to form reactive disodium indol-l-ide-2-thiolate intermediates that were treated with alkyl halides to give the desired indole derivatives in a one-pot process. The method has been applied to the construction of three new indole-fused tricyclic structures by using alpha,omega-dibromoalkanes.