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1.
A Minor New Flavone from Scutellaria baicalensis Georgi 总被引:1,自引:0,他引:1
A new flavone,6,2′-dihydroxy-5,7,8,6′-tetramethoxyflavone,was isolated from the roots of Scutellaria baicalensis. Its structure was established on the basis of spectral evidences. 相似文献
2.
Takahiro Hosoya 《Tetrahedron》2005,61(29):7037-7044
From the fresh leaves of Wasabia japonica Matsum., five novel flavonoids 1-5, isovitexin derivatives having a trans-sinapoyl group at C-7, were isolated together with five known flavonoids, and their structures were elucidated on the basis of their spectroscopic data (NMR, MS, UV, and IR) and chemical evidence. 相似文献
3.
Kin-ichi Oyama 《Tetrahedron》2004,60(9):2025-2034
We have succeeded in the first total synthesis of apigenin 7,4′-di-O-β-d-glucopyranoside (1a), a component of blue pigment, protodelphin, from naringenin (2). Glycosylation of 2 according to Koenigs-Knorr reaction provided a monoglucoside 4a in 80% yield, and this was followed by DDQ oxidation to give apigenin 7-O-glucoside (12a). Further glycosylation of 4′-OH of 12a with 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl fluoride (5a) was achieved using a Lewis acid-and-base promotion system (BF3·Et2O, 2,6-di-tert-butyl-4-methylpyridine, and 1,1,3,3-tetramethylguanidine) in 70% yield, and subsequent deprotection produced 1a. Synthesis of three other chiral isomers of 1a, with replacement of d-glucose at 7 and/or 4′-OH by l-glucose (1b-d), and four chiral isomers of apigenin 7-O-β-glucosides (6a,b) and 4′-O-β-glucosides (7a,b) also proved possible. 相似文献
4.
Takumi Furuta 《Tetrahedron》2004,60(42):9375-9379
The total synthesis of anti-inflammatory active flavone C-glycoside isolated from oolong tea extract is achieved. Introducing a C-glucosyl moiety to an aryl system and constructing a fused tetracyclic ring characteristic to this natural product were conducted based on the O-to-C rearrangement of sugar moiety and the successive intramolecular Mitsunobu reaction, respectively. This concise and efficient synthetic pathway is applicable to the large-scale synthesis of target flavone and for constructing a large library of related compounds. 相似文献
5.
TSIM Karl Wah-keung 《高等学校化学研究》2010,(2)
Flavonoids exhibit a wide range of biological activities including anti-inflammatory activity,while some 1,3-benzoxazine derivatives show anti-inflammatory activity.In order to explore the novel anti-inflammatory agents,based on the principles of bioisosterism and hybridization,ten novel chromeno[8,7-e][1,3]oxazin-4-ones were synthesized and characterized with IR,1H NMR,MS and elemental analyses.The anti-inflammatory activities of the target compounds were evaluated via the croton oil-induced ear oedema tes... 相似文献
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7-取代三唑硫乙氧基黄酮衍生物的合成及生物活性 总被引:1,自引:0,他引:1
7-羟基黄酮与过量1,2-二溴乙烷反应得到7-溴乙氧基黄酮,将其分别与3-取代-4-氨基-1,2,4-三唑-5-硫酮肉桂醛席夫碱、3-取代-4-苯基-5-巯基-1,2,4-三唑、3-(α-萘亚甲基)-5-巯基-1,2,4-三唑及3-巯基-5-氨基-1,2,4-三唑肉桂醛席夫碱反应,得到4类共16个7-三唑硫乙氧基黄酮类衍生物.采用红外光谱(IR)、核磁共振氢谱(1H NMR)、质谱(MS)及元素分析(EA)等方法对化合物的结构进行了确证.测定了目标化合物清除超氧自由基(O-·2)、羟自由基(·OH)和2,2-二苯基-1-苦味酰基自由基(DPPH·)的活性及总还原能力,并测定了其抗菌活性.结果表明,多数化合物在0.5 mg/m L浓度时具有抗DPPH·活性,其中7-(5-苯亚甲基-4-苯基烯丙亚胺基-1,2,4-三唑-3-硫乙氧基)黄酮(1i)活性较强;多数化合物表现了较好的抑菌活性,其中7-(5-苯亚甲基-4-苯基-1,2,4-三唑-3-硫乙氧基)黄酮(2c)对大肠杆菌、金黄色葡萄球菌和黑曲霉均具有较强的抑制作用. 相似文献
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Flavone ( 1 ) was easily reduced by using the electrochemical method to give two hydrodimers of 2,2′‐biflavanone(racemate) ( 5a ) and 2,2′‐biflavanone(meso) ( 5b ) and one reductive product of flavanone ( 6 ). Their yields were dependent on the nature of electrodes, the kinds of supporting electrolytes and the reaction temperature. They were found to afford higher yields of 2,2′‐biflavanone(racemate) ( 5a ) and 2,2′‐biflavanone (meso) ( 5b ) (32.4% and 24.8%, 35.8% and 13.4%, respectively,) in the reaction conditions of Pb(‐)/C(+)‐H2SO4‐7F/mol and C(‐)/C(+)‐H2SO4‐5F/mol. 相似文献
10.
Nand K. Narain 《光谱学快报》2013,46(12):865-875
A rare flavone, Genkwanin, was isolated by column and preparative thin layer chromatography of a chloroform extract of the leaves of Vernonia fasciculata Michx. Spectral studies (NMR, IR, UV and MS) and a comparison with data for closely related compounds has been made. 相似文献