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11.
Angela Sandulache Artur M. S. Silva José A. S. Cavaleiro 《Monatshefte für Chemie / Chemical Monthly》2003,134(4):551-563
Summary. New benzo[b]xanthone derivatives, having substituents in the A and D rings, were prepared from cycloaddition reactions of chromone-3-carboxaldehydes
with ortho-benzoquinodimethanes, generated in situ from 1,3-dihydrobenzo[c]thiophene 2,2-dioxide, followed by oxidation of the obtained diastereomeric adducts. The structure of all compounds was fully
established by 1D and 2D NMR, MS, and elemental analysis. The stereochemistry of the obtained diastereomeric cycloadducts
was established by NOESY experiments.
Corresponding author. E-mail: arturs@dq.ua.pt
Received September 16, 2002; accepted September 20, 2002 相似文献
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Yulin Ren Esperanza J. Carcache de Blanco Leonardus B.S. Kardono Heebyung Chai Norman R. Farnsworth Steven M. Swanson Yuanqing Ding Jannie P.J. Marais A. Douglas Kinghorn 《Tetrahedron》2010,66(29):5311-5320
A new biflavonoid (1), a new xanthone enantiomer (2), five new caged xanthones (3-7), and several known compounds were isolated from the stem bark of Garcinia lateriflora, collected in Indonesia. The structures of the new compounds were determined by analysis of spectroscopic data, and the absolute configuration of the caged xanthones was shown for the first time at carbons 5, 7, 8, 8a, 10a, and 27, by analysis of COSY and NOESY NMR and ECD spectra. The biflavonoids exhibited proteasome-inhibitory activity, and the known compound, morelloflavone (8) was found to have the greatest potency (IC50=1.3 μM). The caged xanthones were cytotoxic toward HT-29 cells, with the known compound, morellic acid (10) being the most active (ED50=0.36 μM). However, when tested in an in vivo hollow fiber assay, it was inactive at the highest dose tested (20 mg/kg). 相似文献
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Tao Xie Chaoying Zheng Kuanwei Chen Haibing He Shuanhu Gao 《Angewandte Chemie (International ed. in English)》2020,59(11):4360-4364
A highly convergent approach was developed to achieve the first asymmetric and scalable total synthesis of FD‐594, a complex polycyclic xanthone natural product from Streptomyces sp. TA‐0256, in a longest linear sequence (LLS) of 20 steps. The trans‐9,10‐dihydrophenanthrene‐9,10‐diol fragment (B‐C‐D ring) was generated through a new strategy involving asymmetric dihydroxylation followed by Cu‐mediated oxidative cyclization. Late‐stage stereoselective glycosylation assembled the angular hexacyclic framework with a β‐linked 2,6‐dideoxy trisaccharide fragment. 相似文献
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T. M. Mikhailova L. M. Tankhaeva E. E. Shul'ts G. A. Tolstikov 《Chemistry of Natural Compounds》2005,41(5):513-515
1-Hydroxy-2,3,4,5-tetramethoxyxanthone, which is used as a standard for quantitative determination of the total content of
γ-pyrones, was isolated from the aerial part of Halenia corniculata L. Cornaz., an available raw material in Russia. A method for preparing standard 1-hydroxy-2,3,4,5-tetramethoxyxanthone was
developed.
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Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 420–421, September–October, 2005. 相似文献
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Pauline Menelle Kévin Cottet Yann Fromentin Thomas Gaslonde François-Hugues Porée Didier Buisson Marie-Christine Lallemand 《Tetrahedron letters》2017,58(52):4876-4879
Guttiferone A and cyclized analogs are naturally occurring polycyclic polyprenylated acyl phloroglucinols possessing antiparasitic activities. Naturally occurring xanthones possess increased activity, but are either rare or difficult to synthesize. In this paper, three optimized methodologies to access natural, hydroxylated and non-natural xanthonic skeletons from guttiferone A are described. These compounds will serve as starting materials for further SAR studies. 相似文献
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ShiMingDENG YouXingZHAO YuQingLIU JunZHOU 《中国化学快报》2005,16(5):623-624
Two new xanthones, 1,6,8-trihydroxy-2,3-methylenedioxyxanthone 1 and 1,4-dihydroxy-6, 7-methylenedioxyxanthone 2, were isolated from the roots of Polygala crotalarioides. Their structures were elucidated by spectroscopic and chemical methods. 相似文献
20.
Yinghui Duan Yi Dai Liuyuan Chen Mingli Liu Yaolan Li Xinsheng Yao 《Magnetic resonance in chemistry : MRC》2012,50(9):642-645
Four new xanthones, 1‐methoxy‐3,7,8‐trihydroxyxanthone (1), 1‐methoxy‐4,7,8‐trihydroxyxanthone (2), 1‐methoxy‐4,7‐dihydroxyxanthone (3), and 1,4‐dimethoxy‐2,7‐dihydroxyxanthone (4) were isolated from the stems of Cratoxylum cochinchinense along with four known xanthones (5–8). The structures of new compounds were determined by extensive spectroscopic analyses, mainly 1D and 2D NMR and HRESIMS data. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献