Synthesis of Zanthoxyline and Its Related Compounds: Revision of the Reported Structure

Abstract

Benzo[c]phenanthridine alkaloid, zanthoxyline, was synthesized through an intramolecular biaryl coupling reaction of N-naphthylbenzamide derivative using a palladium reagent. Comparison of the NMR data for the synthetic product with that reported previously revealed that the proposed structure was incorrect. Synthesis of the related compounds suggested that the correct structure of zanthoxyline is the previously known decarine.