Synthesis of 5-(7′-indolyl)oxazoles and 2,5-di-(7′-indolyl)oxazoles

The synthesis of 7-aminoacetylindoles was achieved via the hydrogenation of 7-acylcyanides, which were produced through the oxidation of indole-7-cyanohydrin silylether intermediates. 7-Oxotryptamines were subsequently converted into 5-(7′-indolyl)oxazoles by reaction with acetic anhydride followed by phosphoryl chloride, and to 2,5-di-(7′-indolyl)oxazoles by reaction with 7-trichloroacetylindoles followed by phosphoryl chloride.