Hodgkinsonia

The rather remarkable alkaloid hodgkinsine from Hodgkinsonia frutescens C. T. White is almost certainly related to the chimonanthine-folicanthine pair. This relation is the more remarkable because Hodgkinsonia F. Muell. belongs to the family Rubiaceae, which does not have obvious affinities with Calycanthaceae. 

Hodgkinsine (20).— The trimeric optically active hodgkinsine (20 CjaHagNg) is found in Hodgkinsonia frutescens F. Muell. It was originally concluded to be an isomer of calycanthine (1) but recent investigations have led unambiguously to structure (20) for this alkaloid. 

Quadrigemine A (27) and Quadrigemine B (28). —These two isomeric alkaloids (C44H50N8, M = 690) occur together with hodgkinsine in Hodgkinsonia frutescens F. Muell. 

Arariba rubra Mart, (see Sickingia rubra K. Schum.) Hodgkinsonia frutescens F. Muell. b ... 

The notable work by Parry and Smith on the structure of quadrigemines A and B, two minor alkaloids of Hodgkinsonia frutescens F. MuelL, has been published.Both alkaloids are composed of four N, -methyltryptamine units, and are the first tetrameric structures to be encountered. The structure of quadrigemine A (251) follows from its facile Hofmann degradation to a tetra-... 

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