Quadrigemines-A and-B, two minor alkaloids of Hodgkinsonia frutescens F. Muell
The structures of two minor alkaloids of Hodgkinsonia frutescens F. Muell., quadrigemines-A and -B, have been shown by chemical degradation to be (2)(as a mixture of diastereoisomers) and (14) respectively (no stereochemistry). A tentative stereochemical assignment, based mainly on optical rotations, can however be made for the quadrigemine-A mixture, which can be seen as an approximately 1 : 1 mixture of diastereoisomer (5) and one (or a mixture of both) of the meso-diastereoisomers. It is noteworthy that these are the first examples of alkaloid structures made up of four tryptamine units.