Alkaloids of Daphnandra species. Part VIII. The structure of repanduline. The evidence based on mass spectrometry and nuclear magnetic resonance
High resolution mass spectrometry has established the molecular formula of repanduline and its key degradation products. The highly characteristic breakdown patterns of bisbenzyltetrahydroisoquinoline alkaloids permit the chemically labile functional groups (enol-ether and carbonyl functions) to be located in a small portion of the repanduline skeleton. The relative location of the enol-ether and carbonyl functions is strongly supported by the n.m.r. spectra of repanduline and its reduction products, as are other unusual features of the repanduline skeleton.