Alkaloids from Dionchophyllaceae

Beside the Ancistrocladaceae, only one other plant family so far has been found to produce naphthyl isoquinoline alkaloids (see also Section IV,B), the Dionchophyllaceae (31-33). Triphyophyllum peltatum (Hutch, et Dalz.) Airy Shaw is a large liana (34), endemic to the rain forests of West Africa. From the twigs of this plant, Bruneton and Cave isolated a new alkaloid, named tri-phyophylline (57), which, in contrast to all kno n Ancistrocladus alkaloids (see Section II), has only one oxygen function on the isoquinoline part of the molecule. No degradation reactions have been described for any of the Triphyophyllum alkaloids. Based exclusively on spectral evidence, triphyophylline was assigned the structure 23 (see Table II). The stereochemistry of the two 

Naphthyl Isoquinoline Alkaloids from Ancistrocladus Plants  

Formula (mol wt), structure Occurrence mp (°C) [ ]d (solvent) Methods for structural elucidation 

By similar arguments, the structure of the isomeric alkaloid isotriphyophylline was interpreted as 24, with a relative cis configuration of the two secondary methyl groups, because its N-benzyl derivative showed a singlet in its 60-MHz NMR (33). The possibility that isotriphyophylline might be, for example, the atropisomer of 23 was not regarded. 

Bruneton s last communication (55) on naphthyl isoquinoline alkaloids includes work on the related plant D. tholonii Baill., also belonging to the Di-onchophyllaceae. It is not clear, however, which of the alkaloids 24, 25, 26, or 29, mentioned above, occur in this species. 

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Table II summarizes the occurrence, structures, and physical data of alkaloids isolated from Dionchophyllaceae and includes the methods applied for their structural elucidation.

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