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.
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Tovopyrifolin C and Amentoflavone from the leaves of the vietnamese plant Calophyllum inophyllum L. Short communication: Tovopyrifolin C and Amentoflavone from the leaves of the vietnamese plant Calophyllum inophyllum L. Received 9th-Dec.-2004 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 suggested a dimeric structure. The 13C-NMR of chemical constituents of Calophyllum 2 pointed to the presence of 28 aromatic inophyllum L. (Clusiaceae) [1] we report in this carbons, which resonated at C from 103.75 to paper the isolation and structure elucidation of 165.12 ppm, and 2 carbonyl groups ( C 183.08, tovopyrifolin C (1) and amentoflavone (2). 183.47). The 1H NMR pointed to the presence Compounds 1 and 2 were isolated by repeated of 12 aromatic protons, which resonated down column chromatography of the resinous part, field at H from 6.24 to 8.12 ppm, and two precipitating from the MeOH extract on hydrogen-bonded hydroxyl groups ( H 12.98 addition of n-hexane. and 13.14). Comparison of the spectra data with The 13C NMR spectrum of 1 showed signals literature [3] allowed to identify 2 as corresponding to 14 carbons, which were amentoflavone. The bond C-3’/C-8” between the assigned by DEPT experiments to be 1 methyl, two flavone units was confirmed by the 4 methine groups and 9 quaternary carbons. The presence of cross peaks in the HMBC spectrum. EIMS showed molecular peak at m/z 274, which allowed, in combination with the obtained 13C OH O NMR, the establishment of its molecular 10 1 8 9 formula as C14H10O6. The spectra data indicated MeO 7 8a 9a 2 a xanthone skeleton with four substituents. Ring 6 B A A beared one hydroxyl group at C-4 ( C 146.93) 3 4b 4a and three neighboring aromatic protons with H HO 5 O 4 7.28 (1H, t, J = 8 Hz, H-2), 7.34 (1H, dd, J = 8, 1.5 Hz, H-3), 7.67 (1H, dd, J = 8, 1.5 Hz, H-1). OH Ring B contained one isolated aromatic proton 1: Tovopyrifolin C 6 5 [ H 6.53, s, H-5], one methoxyl group ( H 3.88, 8 HO 7 8a O 2 1 4 s) at C-7 ( C 131.59), one hydroxyl group at C-6 OH 5 OH 6 4 ( C153.86) and one hydrogen-bonded hydroxyl 6 3 2 3 4a group ( H 13.12) at C-8 ( C 155.39). Extensive 5 4 HO 8 8a O 2 1 3 analysis of 1D and 2D NMR spectra indicated OH O 7 2 that compound 1 was the known xanthone ...