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Kopsia pauciflora

It is of interest to compare the occurrence of the eburnane alkaloids in Malaysian Kopsia with that of the Chinese species (118]. From such a comparison, it would appear that the Malaysian Kopsia (and Leuconotis) species elaborate exclusively eburnane alkaloids of one enantiomeric group (20R, 21R or 20P, 2ip configuration) [18-20,58,110-112,115-119], while the Chinese species appear to elaborate eburnane alkaloids of the opposite enantiomeric group (205, 215 or 20a, 21a configuration) [118,120-122]. Notable exceptions are the dimeric alkaloids kopsoffinol and kopsoffine isolated from the Malaysian Borneo species Kopsia pauciflora [124] which were reported to be constituted from union of kopsinine and dihydroebumamenine units with the 20a, 21a configuration [vide infl-a). [Pg.355]

Two aspidofractinine-type compounds, lahadinines A (233) and B (234), obtained from Kopsia pauciflora are remarkable for having a cyano-substituent at C(21) [162]. The mass-spectra of these alkaloids are characterized by a strong molecular ion (usually also the base peak), with the odd mass indicating the presence of a third nitrogen. Fragments attributable to loss of CN and HCN were also detected in the mass-spectrum and the IR spectrum showed a weak band at ca. 2250 cm. The characteristic H(21) signal was absent in the H NMR... [Pg.368]

Kopsia pauciflora also provided several new alkaloids (268 - 271) [174] possessing a pentacyclic skeleton similar to that of kopsijasminilam (272), deoxykopsijasminilam (273) and 14,15-dehydrokopsijasminilam (274) from the Thai species Kopsia Jasminiflora. The structure of272 was established by X-ray analysis [ISO]. These rare alkaloids can be considered as being derived from an aspidofractinine-type precursor by cleavage of the C(21)-C(20) bond. In pauciflorine A (268) and B (269), the double bond is located between C(19) and C(20) while in... [Pg.374]

Pauciflorines A (268) and B (269) from Kopsia pauciflora are notable for being rare examples of plant-derived indole alkaloids which showed potent inhibitory activity (equivalent to that of the commercial compound, arbutin) towards melanin biosynthesis in cultured B16 melanoma cells at concentrations of 13 and 25 (ig/ml, respectively, without any cytotoxicity towards the cells [19,174,222]. [Pg.418]

Kopsia profunda Kopsia pauciflora Kopsia profunda... [Pg.15]

Kopsamine iV-oxide Kopsia officirudis Kopsia pauciflora... [Pg.17]

Methoxy-lO-demethoxy-kopsidasinine Kopsia pauciflora S 211b 183... [Pg.18]

See other pages where Kopsia pauciflora is mentioned: [Pg.294]    [Pg.326]    [Pg.352]    [Pg.374]    [Pg.388]    [Pg.14]    [Pg.17]    [Pg.17]    [Pg.17]    [Pg.18]    [Pg.18]    [Pg.18]    [Pg.18]    [Pg.49]    [Pg.50]    [Pg.263]    [Pg.263]    [Pg.263]    [Pg.263]    [Pg.263]    [Pg.263]    [Pg.278]    [Pg.291]   
See also in sourсe #XX -- [ Pg.291 , Pg.292 ]



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