Melodinus insulae-pinorum

Melodinus reticulatus Kopsia hainanensis Kopsia hainanensis Catharanthus longiolius Catharanthus ovalis Melodinus fusiformis Melodinus guillauminii Melodinus insulae-pinorum Melodinus morsei Melodinus insulae-pinorum Kopsia teoi Kopsia teoi... 

Insulopinine (624) was isolated from Melodinus insulae-pinorum from New Caledonia (386). It is constituted from the linkage of kopsinine via C(10) to C(16 ) of a (—)-14,15-dehydrovincane unit. The occurrence of the monomer, (—)-14,15-dehydrovincanol ((—)-14,15-dehydroisoeburnamine) (625), provided support for the structure assignment. The observed coupling constants of 10 and 5 Hz for H(16 ) were invoked to support x-substitution at C(16 ) of 624, for which the optical rotation was not reported. 

Five new alkaloids from the leaves and stems of Kopsia profunda Mgf., another Malaysian species, have been shown to be 16,17-didehydro-Aa-methoxycarbonyl-ll,12-methylenedioxykopsinine (175) [the dehydration product of kopsamine (158)], 16,17-didehydro-12-methoxy-Aa-methoxycarbonylkopsinine (176), 16,17-didehydro-12-hydroxy-Na-methoxycarbonylkopsinine (177), and the A7-oxides of 175 and 176 (169,170). 19)3-Hydroxyvenalstonine (178), not previously known as a natural product, has been reported to occur in Melodinus guillaummii (125), M, reticulatus Boiteau (108), and M. insulae-pinorum Boiteau (158). Its structure was deduced from its mass spectrum and comparison with that of venalstonine, and confirmed by its hydrogenation to 19/ hydroxykopsinine (108). Both 3-oxovenalstonidine (179) and 19/3-hydroxyvenalstonidine... 

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