- 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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- An efficient synthesis of procyanidins using equimolar condensation of catechin and/or epicatechin catalyzed by ytterbium triflate
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Stereoselective synthesis of catechin and epicatechin dimers under intermolecular condensation of equimolar amount of catechin derivatives catalyzed by Yb(OTf)3. The coupled products were successfully converted to procyanidins B1, B2, B3, and B4, respectively. Procyanidins B1, B2, B3, and B4 could be used as standard compounds for identifying the polyphenols in natural source.
- Mohri, Yoshihiro,Sagehashi, Masayoshi,Yamada, Taiji,Hattori, Yasunao,Morimura, Keiji,Hamauzu, Yasunori,Kamo, Tsunashi,Hirota, Mitsuru,Makabe, Hidefumi
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experimental part
p. 549 - 563
(2009/12/07)
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- Scale-Up Syntheses of Two Naturally Occurring Procyanidins: (-)-Epicatechin-(4β,8)-(+)-catechin and (-)-Epicatechin-3-0-galloyl- (4β, 8)-(-)-epicatechin-3-0-gallate
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A scaleable process for the synthesis of two naturally occurring procyanidins, namely (-)-epicatechin-(4β,8)-(+)-catechin (1) and(-)-epiratechin-3-O-galloyl-(4β,8)-(-)-epicatechin-3-O-gallate (2), is described. The key steps were highlighted by improvements for the benzylation of (+)-catechin (3), stereo-selective reduction of the C-3 keto group of (2A)-5,7,3′,4′-tetrakis(benzyloxy)flavan-3-one (10), and coupling between 4-hydroxyethoxy-5,7,3′,4′-tetra-O-benzyl-(-)-epicatechin (11) and 5,7,3′,4′-tetra-O-benzyl-(+)-catechin (4) or 5,7,3′,4′-tetra-O-benzyl-(-)-epicatechin (6), respectively. The debenzylation performed in a biphasic system resulted in an improved yield and purity of the target compounds. The chemistry was scaled-up to produce multigram quantities of the title compounds (1 and 2) for various in vitro, ex vivo, and in vivo studies. Moreover, the scale-up process provided a detailed description for the preparation of multihundred to kilogram scale quantities of intermediates used in the synthesis of these two titled procyanidins.
- Sharma, Pradeep K.,Kolchinski, Alexander,Shea, Helene A.,Nair, Jayesh J.,Gou, Yanni,Romanczyk Jr., Leo J.,Schmitz, Harold H.
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p. 422 - 430
(2012/12/31)
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- Synthetic studies of proanthocyanidins. Part 5.1 Highly stereoselective synthesis and inhibitory activity of Maillard reaction of 3,4-trans catechin and epicatechin dimers, procyanidin B1, B2, B3, B4 and their acetates
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TMSOTf-catalyzed condensation of a potential electrophile with a nucleophile was achieved with a high level of 3,4-trans condensation, and we succeeded in the stereoselective synthesis of procyanidin B2 and its peracetate. Studies on the inhibitory activity of the Maillard reaction of four 3,4-trans series of catechin and epicatechin dimers, procyanidin B1, B2, B3 and B4, and their peracetates were also carried out.
- Saito, Akiko,Nakajima, Noriyuki,Matsuura, Nobuyasu,Tanaka, Akira,Ubukata, Makoto
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p. 479 - 489
(2007/10/03)
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- Synthetic studies of proanthocyanidins. Part 4. The synthesis of procyanidin B1 and B4: TMSOTf-catalyzed cyclization of catechin and epicatechin condensation
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Highly stereoselective synthesis of 3,4-trans series of (+)-catechin and (-)-epicatechin dimers under intramolecular condensation is described. Intramolecular condensation achieved an equimolar amount of coupling with 3,4-trans stereoselectivity and we succeeded in the synthesis of two 3,4-trans natural procyanidins, procyanidin-B1 and B4.
- Saito, Akiko,Nakajima, Noriyuki,Tanaka, Akira,Ubukata, Makoto
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p. 287 - 298
(2007/10/03)
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