THE ALKALOIDS OF FUMARIACEOUS PLANTS: VIII. CORYDALIS AUREA, WILLD. AND THE CONSTITUTION OF BICUCINE

Abstract

The chemical examination of the alkaloids of Corydalis aurea has shown an unusual complexity and of the total of more than ten alkaloids thus far isolated only six are now described. The record deals chiefly with the stems and leaves of the plant in which protopine was present in exceptionally low concentration (0.025%). Equally exceptional is its high concentration m the roots (1.6%). l-Tetrahydropalmatine constituted the largest fraction of the remaining alkaloids, and its present isolation is the first on record although the d-form was previously known. Two new and well-characterized alkaloids, which have been named capaurine and capauridine, respectively, are isomeric and are best represented by the empirical formula C21H27O5N. Both contain one phenolic hydroxyl and four methoxyl groups, and yield on methylation non-phenolic bases which do not appear to be identical. The presence of two bases, bicuculline and bicucine, which were first recorded in this series of papers, has again been demonstrated.The constitutional analysis of the new bases, as well as the isolation and characterization of the minor alkaloids, is in progress.In an appended note it is shown that bicuculline and bicucine are closely related and interconvertible. The latter is the free γ-hydroxy acid of which the former is the lactone.