Synthesis of Oxazolylindole Alkaloids from Tryptamine and Tryptophan by Oxidation with 2,3-Dichloro-5,6-dicyanobenzoquinone
When N-acyl derivatives of tryptamine and L-tryptophan methyl ester were treated with DDQ (2 equiv) in tetrahydrofuran or other anhydrous solvents, four consecutive reactions, dehydrogenation, nucleophilic cyclization, another dehydrogenation, and isomeri