A Zwitterionic Alkaloid, Containing a Rare Cyclopentadienyl Anion Unit, from the Stem Barks ofDaphniphyllum macropodumMiq.

Abstract

A new Daphniphyllum alkaloid daphnicyclidin L (1), containing a rare cyclopentadienyl anion, which is stabilized as a zwitterion by an internal iminium counterion, was isolated from the stem barks of Daphniphyllum macropodum Miq., together with four known alkaloids: daphnicyclidin D (2), daphnicyclidin H (3), deoxyyuzurimine (4), and yuzurimine (5). The structures were elucidated on the basis of spectroscopic data. The configuration of 1 was elucidated by single-crystal X-ray diffraction crystallography.