Synthesis of Pimprinine and Related Oxazolylindole Alkaloids from N-Acyl Derivatives of Tryptamine and Tryptophan Methyl Ester by DDQ Oxidation

N-Acyl derivatives of tryptamine and L-tryptophan methyl ester were treated with DDQ under anhydrous conditions directly to give pimprinine and related oxazolylindole alkaloids under aqueous conditions, the N-acyl derivatives were readily oxidized to the corresponding 3-keto compounds, which were also converted to the oxazolylindoles by the treatment with POC13.Pimprinine , an alkaloid having antieplepticl and monoamine oxidase inhibitory activitles,2 was first isolated from Streptomyces pimprina3 and synthesized