Isolation and characterization of brachystemidines A-E, novel alkaloids from Brachystemma calycinum

摘要

Five novel alkaloids, brachystemidines A-E (1-5), were isolated from the roots of Brachystemma calycinum. Their structures were established by spectral data, especially by ID and 2D NMR techniques. The crystal structure of brachystemidine D was determined via X-ray diffraction analysis.