- Synthesis of procyanidin B1, B2, and B4 and their anti-inflammatory activity: The effect of 4-alkoxy group of catechin and/or epicatechin electrophiles for condensation
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Abstract: Procyanidin B1, B2, and B3 were synthesized based on a Yb(OTf)3 catalyzed equimolar condensation using methoxy and/or 4-(2-ethoxyethoxy) drivatives as electrophiles. The anti-inflammatory effect of synthetic procyanidin B1, B2, and B4 on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation of mouse ears was examined. Procyanidin B1, B2, B 4 suppressed TPA-induced inflammation of mouse ears by 48%, 34%, and 29%, respectively, at a dose of 200 μg. Their activities are stronger than those of indomethacin and glycyrrhetinic acid, the normally used antiinflammatory agent.
- Katoh,Oizumi,Mohri,Hirota,Makabe
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scheme or table
p. 233 - 238
(2012/07/28)
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- Cationic zirconocene- or hafnocene-based Lewis acids in organic synthesis: Glycoside-flavonoid analogy
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Cationic metallocene species, generated from Cp2MCl2 and AgClO4 (M=Zr, Hf), were used for the glycosylation of catechin derivative 2, enabling a concise synthesis of a glycosyl flavonoid, astilbin (1). Further study revealed the efficiency of this Lewis acidic species for SN1-type activation of the C(4) position of catechin derivative 11, enabling selective substitution with various nucleophiles.
- Ohmori, Ken,Hatakeyama, Keisuke,Ohrui, Hiroki,Suzuki, Keisuke
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p. 1365 - 1373
(2007/10/03)
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- Synthetic studies of proanthocyanidins. Highly stereoselective synthesis of the catechin dimer, procyanidin-B3.
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A stereoselective synthesis of benzylated procyanidin-B3, a condensed catechin dimer, is described. Condensation of 5,7,3',4'-tetrabenzylcatechin with (2R,3S,4S)-5,7,3',4'-tetrabenzyloxy-3-acetoxy-4-methoxyflavan as an electrophile in the presence of TiCl4 led to octabenzylated procyanidin-B3 stereoselectively.
- Saito, Akiko,Nakajima, Noriyuki,Tanaka, Akira,Ubukata, Makoto
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p. 1764 - 1767
(2007/10/03)
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- First synthesis of astilbin, biologically active glycosyl flavonoid isolated from Chinese folk medicine
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A synthetic route to a biologically active glycosyl flavonoid, astilbin (1), was developed. The tetra-benzyl ether 4, derived from (+)-catechin, was glycosylated with the L-rhamnosyl donor 10 by using Cp2HfCl2-AgClO4, and subsequent oxidation of the C(4)position of the flavan skeleton followed by deprotection gave 1. (C) 2000 Elsevier Science Ltd.
- Ohmori, Ken,Ohrui, Hiroki,Suzuki, Keisuke
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p. 5537 - 5541
(2007/10/03)
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