- 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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experimental part
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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- Synthesis of procyanidins by stepwise- and self-condensation using 3,4-cis-4-acetoxy-3-O-acetyl-4-dehydro-5,7,3′,4′-tetra-O-ben zyl-(+)-catechin and (-)-epicatechin as a key building monomer
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3,4-cis-4-Acetoxy-3-O-acetyl-4-dehydro-5,7,3′,4′-tetra-O-ben zyl-(+)-catechin (1a) or (-)-epicatechin (1b) reacted high regio- and stereo-selectively with 1.5 equiv of the 5,7,3′,4′-tetra-O-benzyloxyflavan-3-ol (4a or 4b) in the presence of 1 equiv of TMSOTf to give the corresponding procyanidins. On the other hand, the self-condensation of 1a in the presence of a catalytic amount of B(C6F5)3 afforded wide-range procyanidins from dimer to 15-mer like a biomass.
- Oyama, Kin-ichi,Kuwano, Miyuki,Ito, Mie,Yoshida, Kumi,Kondo, Tadao
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p. 3176 - 3180
(2008/09/20)
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- An efficient synthesis of procyanidins. Rare earth metal Lewis acid catalyzed equimolar condensation of catechin and epicatechin
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Stereoselective synthesis of catechin and epicatechin dimers under intermolecular condensation is achieved by an equimolar amount of coupling catalyzed by Yb(OTf)3. The coupled products were successfully converted to procyanidin B1, B2, B3, and B4.
- Mohri, Yoshihiro,Sagehashi, Masayoshi,Yamada, Taiji,Hattori, Yasunao,Morimura, Keiji,Kamo, Tsunashi,Hirota, Mitsuru,Makabe, Hidefumi
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p. 5891 - 5894
(2008/02/09)
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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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