Syntheses of Substituted L- and D-Tryptophans

Abstract

Several 5-substituted N_b-methoxycarbonyl-L- and -D-tryptophan derivatives were synthesized from proline by a new route involving electrochemical oxidation, as well as by the known procedures. Removal of the N_b-methoxycarbonyl group was accomplished by treatment with Me₃SiI in refluxing chloroform, then alkaline hydrolysis of the methyl esters afforded 5-substituted L- and D-tryptophans with high optical purities.