Kopsia officinalis

Kopsia officinalis Tsiang et P. T. Li enjoys a reputation in popular Chinese medicine for the alleviation of gout and rheumatism, and as an analgesic... 

Five alkaloids, 244-248, have been isolated that contain a new ring system resulting from the fission of the 16,17-bond in fruticosine. The structure of methyl 11,12-methylenedioxy-chanofruticosinate (Alkaloid C, 246), a constituent of the leaves of Kopsia officinalis (190) and K. arborea Bl. (191), was established by X-ray crystallographic analysis (190). Alkaloids A and B lack the methylenedioxy group, and it was deduced, on the basis... 

Three dihydroindole alkaloids isolated from Kopsia officinalis... 

Kopsia officinalis, endemic to the Yunnan province of China, gave the bisin-dole alkaloid, ( + )-kopsoffine (613) (377). As in the case of norpleiomutine (606), the mass spectral fragmentation was similar to that of (—)-pleiomutine (607), except that the of 613 (m/z 616) is 14 mass units less than that of 607. The H NMR spectrum confirmed the absence of NMe in the kopsinine half, while the H(16) coupling constants of 11 and 5 Hz indicated that H(16 ) is axial or P, and that the C(16 ) substitution is a. Comparison of the C NMR spectral data with those of (—)-kopsinine (608) and (+ )-vincamine provided further support for the proposed structure in which the eburnane half is the optical antipode of the corresponding half in (—)-norpleiomutine (606). Confirmation of this was provided by semisynthesis, from the condensation of ( + )-eburnamine (614) (from LiAlH4 reduction of (—)-eburnamonine 615) with (—)-kopsinine (608) under acidic conditions, which led to a product identical with (+ )-kopsoffine. 

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