Dihydroerysovine, a new erythrina alkaloid

A new Erythrina alkaloid designated as dihydroerysovine was isolated from Cocculus trilobus DC. (Menispermaceae). From chemical and spectroscopic studies, especially INDOR and NOE techniquse, the structure (III) was assigned to this alkaloid. The utility of INDOR and NOE methodes for the determination of substituent pattern on an aromatic ring of Erythrina alkaloids was ascertained.