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

Short communication:<br /> <br /> <br /> <br /> Tovopyrifolin C and Amentoflavone from the leaves<br /> of the vietnamese plant Calophyllum inophyllum L.<br /> Received 9th-Dec.-2004<br /> Nguyen Thi Minh Hang, Nguyen Quyet Chien, Nguyen Van Hung<br /> Institute of Chemistry, Vietnamese Academy of Science and Technology<br /> <br /> In continuation of our research on the suggested a dimeric structure. The 13C-NMR of<br /> chemical constituents of Calophyllum 2 pointed to the presence of 28 aromatic<br /> inophyllum L. (Clusiaceae) [1] we report in this carbons, which resonated at C from 103.75 to<br /> paper the isolation and structure elucidation of 165.12 ppm, and 2 carbonyl groups ( C 183.08,<br /> tovopyrifolin C (1) and amentoflavone (2). 183.47). The 1H NMR pointed to the presence<br /> Compounds 1 and 2 were isolated by repeated of 12 aromatic protons, which resonated down<br /> column chromatography of the resinous part, field at H from 6.24 to 8.12 ppm, and two<br /> precipitating from the MeOH extract on hydrogen-bonded hydroxyl groups ( H 12.98<br /> addition of n-hexane. and 13.14). Comparison of the spectra data with<br /> The 13C NMR spectrum of 1 showed signals literature [3] allowed to identify 2 as<br /> corresponding to 14 carbons, which were amentoflavone. The bond C-3’/C-8” between the<br /> assigned by DEPT experiments to be 1 methyl, two flavone units was confirmed by the<br /> 4 methine groups and 9 quaternary carbons. The presence of cross peaks in the HMBC spectrum.<br /> EIMS showed molecular peak at m/z 274, which<br /> allowed, in combination with the obtained 13C OH O<br /> NMR, the establishment of its molecular 10 1<br /> 8 9<br /> formula as C14H10O6. The spectra data indicated MeO 7 8a 9a<br /> 2<br /> a xanthone skeleton with four substituents. Ring<br /> 6<br /> B A<br /> A beared one hydroxyl group at C-4 ( C 146.93) 3<br /> 4b 4a<br /> and three neighboring aromatic protons with H HO 5 O 4<br /> 7.28 (1H, t, J = 8 Hz, H-2), 7.34 (1H, dd, J = 8,<br /> 1.5 Hz, H-3), 7.67 (1H, dd, J = 8, 1.5 Hz, H-1). OH<br /> Ring B contained one isolated aromatic proton 1: Tovopyrifolin C<br /> 6' 5'<br /> [ H 6.53, s, H-5], one methoxyl group ( H 3.88, 8<br /> HO 7 8a O 2 1' 4'<br /> s) at C-7 ( C 131.59), one hydroxyl group at C-6 OH 5'''<br /> OH<br /> 6''' 4'''<br /> ( C153.86) and one hydrogen-bonded hydroxyl 6 3 2'<br /> 3'<br /> 4a<br /> group ( H 13.12) at C-8 ( C 155.39). Extensive 5 4 HO 8''<br /> 8a'' O 2'' 1''' 3'''<br /> analysis of 1D and 2D NMR spectra indicated OH O 7'' 2'''<br /> <br /> that compound 1 was the known xanthone 6'' 3''<br /> 4a''<br /> 5'' 4''<br /> tovopyrifolin C. It was previously isolated from<br /> Calophyllum bracteacum, Centaurium OH O<br /> linafolium and Pentadowna butyraceae [2]. 2: Amentoflavone<br /> 1 13<br /> Both H NMR and C NMR of 2 showed<br /> two sets of peaks with nearly equal intensity and Tovopyrifolin C (1): yellow needles, mp 264-<br /> virtually identical chemical shifts, which 265oC. IR (KBr cm-1) max: 3466, 3263 (OH),<br /> iii<br /> 1654 >C=O). 1H-NMR (500 MHz, acetone-d6): 8.9 Hz, H-3’” and H-5’”). 13C NMR (125 MHz,<br /> 3.88 (3H, s, H-10), 6.53 (1H, s, H-5), 7.28 (1H, acetone-d6): 165.12 (C-1), 104.28 (C-2), 183.08<br /> t, J = 8 Hz, H-2), 7.34 (1H, dd, J = 8, 1.5 Hz, H- (C-4), 105.51 (C-4a), 163.34 (C-5), 99.77 (C-6),<br /> 3), 7.67 (1H, dd, J = 8, 1.5 Hz, H-1). 13C NMR 158.85 (C-7), 94.83 (C-8), 164.96 (C-8a),<br /> (125 MHz, acetone-d6): 116.19 (C-1), 124.83 123.26 (C-1’), 132.61 (C-2’), 120.92 (C-3’),<br /> (C-2), 121.34 (C-3), 146.93 (C-4), 146.14 (C- 160.34 (C-4’), 117.54 (C-5’), 128.82 (C-6’),<br /> 4a). 159.27 (C-4b), 94.77 (C-5), 153.86 (C-6), 165.12 (C-2”), 103.75 (C-3”), 183.47 (C-4”),<br /> 131.59 (C-7), 155.39 (C-8), 104.03 (C-8a), 105.34 (C-4a”), 162.72 (C-5”), 99.82 (C-6”),<br /> 182.16 (C-9), 121.78 (C-9a), 60.77 (C-10). MS 162.77 (C-7”), 104.46 (C-8”), 156.13 (C-8a”),<br /> m/z (%): 274 (M+., 76), 259 ([M-CH3]+, 60, 231 123.34 (C-1’”), 129.14 (C-2’” and C-6’”),<br /> (100), 137 (11), 93 (10), 69 (15), 53 (13). 116.74 (C-3’”and C-5’”), 161.87 (C-4’”).<br /> Amentoflavone (2): small yellow crystals, mp<br /> References<br /> 300 - 301oC. IR (KBr cm-1) max: 3414, 3178<br /> (OH), 1653 (>C=O), 1607, 1573, 1494 ( C=C 1. N. T. M. Hang, N. Q. Chien, N. V. Hung,<br /> aromatic ring), 1168 (C-O-C). 1NMR (500 Vietnam Journal of Chemistry (in press).<br /> MHz, acetone-d6): 6.72 (1H, s, H-3), 6.24 (1H,<br /> d, J = 2.1 Hz, H-6), 6.51 (1H, d, J = 2.1, H-8), 2. Dictionary of Natural Products on CD-ROM,<br /> 8.12 (1H, d, J = 2.4, H-2’), 7.24 (1H, d, J = 8.6 version 12:1, Chapman & Hall, 1982-2004.<br /> Hz, H-5’), 8.08 (1H, dd, J = 8.6, 2.4 Hz, H-6’), 3. M. V. Tri , P. T. Son, D. A. Tuan , D. N. Tu,<br /> 6.64 (1H, s, H-3”), 6.44 (1H, s, H-6”), 7.64 (1H, Vietnam Journal of Chemistry, Vol. 40, No. 3,<br /> d, J = 8.9 Hz, H-2’” and H-5’”), 6.82 (2H, d, J = 24 - 27 (2002).<br /> <br /> <br /> <br /> <br /> iv<br />