[A new alkaloid from Menispermum dauricum DC--N-desmethyldauricine].

A new phenolic dauricine-type alkaloid together with the know dauricine were isolated from the rhizoma of Menispermum dauricum DC cultivated in Xianning district, Hubei province. Dauricine was obtained as the major alkaloid and was confirmed by comparison with authentic sample. The new alkaloid is an unstable white powder: Based on spectrometric analysis (UV, IR, FAB-MS and 1HNMR) and N-methylation which offered dauricine dimethiodide (V), the structure was elucidated as RR, N-desmethyldauricine (II), which was isolated for the first time from nature.