Constituents of Tropical Medicinal Plants, LXIII: Synthesis of 2‐Methoxyonychine Alkaloids ‐ Structure Revision of Oxylopidine

Abstract

Abstract Condensation of β‐aminocinnamic acid esters with 3‐chloro‐2‐methoxy‐crotonaldehyde opened an easy access to 2‐phenyl‐5‐methoxy‐4‐methylnicotinic acid esters which were cyclized by polyphosphoric acid to yield the corresponding 2‐methoxyonychines. By this method a number of 2‐methoxy‐substituted onychines were prepared for the first time, i.a. oxylopidine, the structure of which has to be revised.