TAILIEUCHUNG - Tovopyrifolin C and Amentoflavone from the leaves of the vietnamese plant Calophyllum inophyllum L.

In continuation of our research on the chemical constituents of Calophyllum inophyllum L. (Clusiaceae) [1] we report in this paper the isolation and structure elucidation of tovopyrifolin C (1) and amentoflavone (2). Compounds 1 and 2 were isolated by repeated column chromatography of the resinous part, precipitating from the MeOH extract on addition of n-hexane. | SHORT COMMUNICATION TOVOPyRIFOLIN C AND AMENTOFLAVONE FROM THE LEAVES OF THE VIETNAMESE PLANT CALQPHYLLUM INQPHYLLUM L. Received NGUyEN THI MINH HANG NGUyEN QUyET CHIEN NGUyEN VAN HUNG Institute of Chemistry Vietnamese Academy of Science and Technology In continuation of our research on the chemical constituents of Calophyllum inophyllum L. Clusiaceae 1 we report in this paper the isolation and structure elucidation of tovopyrifolin C 1 and amentoflavone 2 . Compounds 1 and 2 were isolated by repeated column chromatography of the resinous part precipitating from the MeOH extract on addition of n-hexane. The 13C NMR spectrum of 1 showed signals corresponding to 14 carbons which were assigned by DEPT experiments to be 1 methyl 4 methine groups and 9 quaternary carbons. The EIMS showed molecular peak at m z 274 which allowed in combination with the obtained 13C NMR the establishment of its molecular formula as C14H10O6. The spectra data indicated a xanthone skeleton with four substituents. Ring A beared one hydroxyl group at C-4 ỖC and three neighboring aromatic protons with ỖH 1H t J 8 Hz H-2 1H dd J 8 Hz H-3 1H dd J 8 Hz H-1 . Ring B contained one isolated aromatic proton ỖH s H-5 one methoxyl group ỖH s at C-7 ỖC one hydroxyl group at C-6 and one hydrogen-bonded hydroxyl group ỖH at C-8 ỖC . Extensive analysis of 1D and 2D NMR spectra indicated that compound 1 was the known xanthone tovopyrifolin C. It was previously isolated from Calophyllum bracteacum Centaurium linafolium and Pentadowna butyraceae 2 . Both 1H NMR and 13C NMR of 2 showed two sets of peaks with nearly equal intensity and virtually identical chemical shifts which suggested a dimeric structure. The 13C-NMR of 2 pointed to the presence of 28 aromatic carbons which resonated at ỖC from to ppm and 2 carbonyl groups ỖC . The 1H NMR pointed to the presence of 12 aromatic protons which resonated

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