- Convenient method of synthesizing aryloxyalkyl esters from phenolic esters using halogenated alcohols
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A facile one-pot synthetic method of building aryloxyalkyl esters was developed using various types of phenolic esters with halogenated alcohols. The ready availability of both starting materials, coupled with the required simple experimental technique, enables the current synthetic method of producing aryloxyalkyl esters in a fast and efficient way. It is noteworthy that acyl transfer was demonstrated in this reaction.
- Jiang, Xueyang,Zhou, Junting,Zhou, Yue,Sun, Haopeng,Xu, Jian,Feng, Feng,Qu, Wei
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supporting information
(2018/08/21)
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- Synthesis of oroxylin A starting from naturally abundant baicalin
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– A new approach to oroxylin A, a monomethylated trihydroxyflavone, is described. The starting material was baicalin, a representative naturally abundant flavonoid glucuronide. First, conditions for the cleavage of the glycosidic bond were established, using a mixture of water and conc. sulfuric acid (5:2) at 121 °C for 40 min. The hydrolysis was performed in a high-pressure steam sterilizer so that the temperature and reaction time were precisely controlled. Subsequent acetylation of the crude material furnished baicalein 6,7-diacetate on a preparative scale and in a reproducible manner. Next, the C-7 position was protected site-selectively with a methoxymethyl (MOM) group, taking advantage of an unexpected sequential migration of the two acetyl groups among the C-5, C-6, and C-7 positions under basic conditions. The removal of the two remaining acetyl groups followed by site-selective methylation of the C-6 position furnished 5-hydroxy-6-methoxy-7-methoxymethoxyflavone (oroxylin A C-7 MOM ether). Finally, by the deprotection of the MOM ether, oroxylin A was obtained in 6 total steps and 62% overall yield from baicalin.
- Fujita, Rie,Hanaya, Kengo,Higashibayashi, Shuhei,Sugai, Takeshi
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p. 1165 - 1174
(2019/07/31)
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- 2-substituted benzopyran-4-one compounds and application thereof
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The invention relates to the technical field of medicine and discloses 2-substituted benzopyran-4-one compounds with a structure shown in general formula I and an application of the compounds in preparation of antifungal drugs and synergistic antifungal drugs. The compounds can be jointly used with azole antifungal drugs, can improve sensibility of drug-resistance bacteria to the azole drugs, reverses drug resistance and produces a synergistic antifungal function.
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Paragraph 0241; 0242; 0243
(2016/10/08)
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- Synthesis of ring A-modified baicalein derivatives
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Baicalein, an important active constituent of the traditional Chinese herb Scutellaria baicalensis, exhibited antitumor activity and inhibitory activity against P-gp 170. The syntheses of 25 baicalein derivatives, 2-26 (Table), are described here (Scheme
- Wang, Jun-Fei,Ding, Ning,Zhang, Wei,Wang, Peng,Li, Ying-Xia
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experimental part
p. 2221 - 2230
(2012/01/14)
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- COMPOUNDS AND METHODS TO INCREASE ANTI-P-GLYCOPROTEIN ACTIVITY OF BAICALEIN BY ALKYLATION ON THE A RING
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The present invention is directed to analogs of baicalein according to formula (I): where R5 is H, (CI-C12)alkyl, (C2-C13)acyl, or an optionally substituted phenyl or benzyl group, an acyl group, a C1-C20 alkyl or ether group, a phosphate, diphosphate, triphosphate or phosphodiester group; R6 and R7 are each independently H, (C1-C12)alkyl, (C2-C13)acyl, or an optionally substituted phenyl or benzyl or together form a -OCR1R20- group wherein each of R1 and R2 is independently H, a C1-C3 alkyl group or an optionally substituted phenyl or benzyl group; and R8 is H, OH, an O-acyl group, a C1,-C4 alkyl or alkoxy group, F, Cl, Br or I, or a pharmaceutically acceptable salt thereof, which exhibit anti-P-glycoprotein activity and methods of enhancing the bioavailability of active compounds, especially orally administered compounds, by inhibition of P-glycoprotein 170 (P-gp 170) and/or CYP450 enzyme, especially CYP450 3A4 enzyme. Pharmaceutical compositions based upon these novel derivatives according to the present invention are also described herein.
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Page/Page column 29
(2010/02/13)
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- Increased anti-P-glycoprotein activity of baicalein by alkylation on the A ring
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The aqueous extract of Scutellariae baicalensis Georgi has inhibitory activity against P-gp 170, a multiple drug resistant gene product. Baicalein, one of the major flavones, was found to be responsible for this activity. The hydroxyl groups of the A ring
- Lee, Yashang,Yeo, Hosup,Liu, Shwu-Huey,Jiang, Zaoli,Savizky, Ruben M.,Austin, David J.,Cheng, Yung-Chi
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p. 5555 - 5566
(2007/10/03)
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