A C30H42N204 alkaloid, corresponding in structure to a dimer of 6,7P-oxidodeoxynupharidine, was isolated from extracts of Nuphar luteum subsp. macrophyllum. The structure was elucidated by chemical and spectral means and was confirmed by the transformation of AB-dehydrodeoxynupharidine to the C30 dimer. A stereoisomeric C30 dimer corresponding to the 6,7a-oxidodeoxynupharidine was prepared and the existence of a mixed dimer was detected. Deoxynupharidin-7@-01 and 7-epideoxynupharidin-7a-01 were obtained in the metal hydride reductions of 6,7P-oxidodeoxynupharidine dimer and 7-epideoxynupharidine-6,7a-diol, respectively.