Ancistrocladus abbreviatus

Isoquinoline alkaloids Ancistrocladus abbreviatus CHCl3-MeOH-0.5% HBr (5 5 3) HSCCC... 

Hoye and co-workers (ref. 92) later reported the total synthesis of ancistrobrevine B (228), isolated from Ancistrocladus abbreviatus (ref. 93) and korupensamine C (229), isolated from Ancistrocladus korupensis. The approach to these natural products also utilised a benzyne cycloaddition to construct the naphthalene moiety. Thus, treatment of the amide 222 and bromide 230 with lithium cyclohexylisopropylamide furnished naphthalene 231 in low yield (Scheme 30). 

The identification of plumbagine (42), however, in Triphyophyllum peltatum 31), as well as in Ancistrocladus abbreviatus Airy Shaw 46), co-occurring with the alkaloids, can be interpreted as a strong indirect indication of a polyacetate pathway in the plants. By 1972, Zenk and co-workers had already found that the naphthoquinone 42 is formed from acetate units, albeit in Drosera and Plumbago species 47). A joint biosynthesis of plumbagine (42) and both molecular moieties, for example, of the alkaloid 23 from the same monocyclic precursor 32 seems evident (Scheme 6). 

Ancistrocladus abbreviatus is widely used in folk medicine (Bringmann et al., 1990). Leaves of the Ancistrocladus tectorius are used in Thailand to treat dysentery and malaria (Tantisewie and Ruchirawat, 1992). 

MkheNamines. Atropisomeric dimeric naphthyl-(tetrahydro)isoquinoline alkaloids from the tropical lianas Ancistrocladus korupensis and A. abbreviatus. C46H48N2O8, Mr 756.89. 

Michellamine B (19), from Ancistrocladus korupensis (formerly considered to be /4. abbreviatus) has been shown to possess potent activity against HIV-1 and HIV-2 (Manfredi et al., 1991 Thomas and Gereau, 1993). 

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