Sulfonation of catechin

Sears, Karl D.

doi:10.1021/jo00795a037

Cited by 19 publications

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“…The reaction product was purified by Sephadex column chromatography and isolated äs an amorphous, white solid. Sears (1972) has already studied sulphonation of catechin and identified the reaction product of catechin with sodium sulphite and sodium bisulphite äs imethyl sulphonate-(3 5 4-diacetoxyphenyl)-2-acetoxy-3-(i,3,5-triacetoxyphenyl) propane after methylation and acetylation. On the basis of his experiments, he concluded that catechin undergoes ready attack by the sulphonate group at C-2 in the pyran ring.…”

Section: Resultsmentioning

confidence: 99%

Molecular Size Distribution of Radiata Pine Bark Extracts and its Effect on Properties

Yazaki¹,

Hillis²

1980

Holzforschung

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Various aqueous extracts from Pinus radiata and Acacia mearnsii barks were fractionated by ultrafiltration on the basis of molecular size* All the monomeric, dimeric and oligomeric compounds were concentrated in the fraction containing compounds with molecular sizes sinailer than a io 3 molecular weight Dextran. High yields of hot-water-soluble material have been obtained from the radiata pine bark and shown to have promise äs a base for adhesives. However, the excessive viscosity of the untreated extracts limits their commercial use. The particularly high viscosity of the ioo°C aqueous extracts of P. radiata bark was reduced markedly by removing either the methanol insolubles or the high polymeric material with a molecular size larger than io e molecular weight Dextran by ultrafiltration. Both the methanol insolubles and the high polymeric material are viscosity control factors. In addition, examination of various extracts and fractions revealed that the molecular size distribution of the extracts is a viscosity control factor. Chromatographie examination of sulphited ioo°C aqueous pine bark extracts revealed a compound with behaviour exactly the same äs the major product from a reaction of catechin with sodium bisulphite. The compound was isolated and identified äs i-sodium sulphonate-(3,4-dihydroxyphenyl)-2-hydroxy-3-(i ,3,5-trihydroxyphenyl) propane. The amounts of Stiasny precipitate produced by various extracts, fractions or the sulphited extracts were determined and found to be lowest in the fraction with molecular sizes smaller than io 3 molecular weight Dextran. Purification of the extracts by ultrafiltration produced extracts having low viscosities and yielding suitable amounts of Stiasny precipitate which indicate high and uniform qualities of extract. Molekulargewichtsverteilung in Rindenextrakten von Radiata Kiefer und ihr Einfluß auf die Eigenschaften ZusammenfassungVerschiedene Rindenextrakte von Pinus radiata und Acacia mearnsii wurden durch Ultrafiltration nach der Molekulargröße fraktioniert. Alle monomeren, dimeren und oligomeren Verbindungen jeder Fraktion wurden konzentriert, wobei die Molekulargewichte kleiner als io 3 , bezogen auf Dextran, waren. Hohe Ausbeuten an heißwasserlöslichen Stoffen ergaben sich bei Radiata Kiefernrinden, die möglicherweise als Grundlage für Bindemittel dienen können; ihre hohe Viskosität begrenzt jedoch ihre wirtschaftliche Anwendung. Die besonders hohe Viskosität der ioo°C Extrakte aus Radiata Kiefernrinde kann beträchtlich vermindert werden entweder durch Entfernen der methanolunlöslichen Stoffe oder durch Entfernen der hochpolymeren Anteile von einem Molekulargewicht über io 6 mittels Ultrafiltration. Die beiden genannten Bestandteile bestimmen die Viskosität. Ferner zeigt die Prüfung der verschiedenen Extrakte und Fraktionen, daß die Molekulargewichtsverteilung in den Extrakten für die Viskosität bestimmend ist. Aus chromatographischen Untersuchungen an sulfitierten ioo°C Rindenextrakten geht hervor, daß hier eine Verbindung mit genau demselben Verhalten vorl...

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Section: Resultsmentioning

confidence: 99%

Molecular Size Distribution of Radiata Pine Bark Extracts and its Effect on Properties

Yazaki¹,

Hillis²

1980

Holzforschung

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“…The chemistry of tannin Sulfonation was little understood, at least with regard to procyanidins, until Foo et al (1983) investigated the reaction of aqueous sodium hydrogen sulfite with the procyanidin-based tannins from Pinus taeda bark. The formation of 3 from catechin had been demonstrated earlier by Sears (1972) with a sodium sulfite-bisulfite medium. A minor reaction product was sodium l-(3,4-dihydroxy phenyl)-2-hydroxy-3-(2, 4,6-trihydroxy phenyl) propane-1-sulfonate (3), formed by acid-catalyzed opening of the pyran ring of catechin (4) and Sulfonation at the benzylic C-2 carbon.…”

Section: Introductionmentioning

confidence: 61%

Sulfonation of Procyanidin Polymers: Evidence of Intramolecular Rearrangement and Aromatic Ring Substitution

Bae¹,

Malan²,

Karchesy³

1994

HFSG

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The reaction of Douglas-fir polymeric procyanidins with aqueous sodium hydrogen sulfite was investigated by gel permeation chromatography (GPC) and the Isolation and Identification of sulfonated derivatives. GPC profiles of molecular weight over time indicated that epicatechin-(4ß)-sulfonate was rapidly formed initially but did not significantly increase over longer reaction time. Undefined oligomeric materials remained in the reaction mixture, which suggests that other reactions compete with simple acid-catalyzed cleavage of the interflavanoid bond and subsequent formation of 4-substituted flavanoid sulfonates. The Isolation of disodium epicatechin-(4,5')-disulfonate and a functionalized chromene derivative gave evidence that aromatic ring Sulfonation and flavanoid C-ring isomerization are t wo such reactions.'Paper 2898 of the Forest Research Laboratory, Oregon State University, Corvallis, OR 97331, U. S. A. Polymeric procyanidinsDouglas-fir (Pseudotsuga menzesii) inner bark was stripped from a freshly fallen tree, cut into Strips, and iinmersed in methanol.Holzforschung / Vol. 48 / 1994 / No. 2

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“…The reaction of Na 2 SO 3 with tannin gives rise to two types of polymers. The first one is formed by reaction of the catechin group in its monomeric form by opening the pyranic ring38 (Fig. 4), while the second is obtained through a reaction of the dimeric form of catechin giving a breaking of the interflavonoid ring in the C‐4, C‐6 (or C‐8) position39 (Fig.…”

Section: Resultsmentioning

confidence: 99%

Hide tanning with modified natural tannins

Tambi¹,

Frediani²,

Frediani³

et al. 2008

J of Applied Polymer Sci

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Tannin from ''Acacia Mearnsii'' usually called Mimosa, is largely employed in vegetal tanning of hide even if the quality of the leather is poorer than that obtained using chromium as tanning agents. However, taking into account the natural resources of this product and its reduced environmental impact, mimosa tannin has been modified to obtain leather having improved properties. Tannin was modified using formaldehyde, urea, a sulfonic acid and a sulfiting agent: The new products show a higher molecular weight than mimosa tannin but maintain a good solubility in water. Modified tannins were characterized through physicochemical and technological tests and evaluated as tanning agents. The properties of tanned leathers obtained using the new tannin products and mimosa were compared. Some of the polymers containing phenolsulfonic acid are good tannin agents, especially those with a suitable molecular weight. The technological and sensorial properties of the leather obtained using modified tannins (distension and strength of grain, tensile strength, elongation, and tear load) are better than those obtained using mimosa when an appropriate ratio of the reagents were employed. At the same time the feeling of the tanned leather was improved and the final products show fullness, elasticity, fluency, reactivity, and a thin and fine grain. Some of the tannins modified with naphtalensulfonic acid show poor tanning properties but good penetration in the leather suggesting their use as auxiliary sintans in the pretanning process. A simple procedure to prepare these modified tanning agents in the course of the tannin extraction is suggested.

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Sulfonation of catechin

Cited by 19 publications

References 0 publications

Molecular Size Distribution of Radiata Pine Bark Extracts and its Effect on Properties

Molecular Size Distribution of Radiata Pine Bark Extracts and its Effect on Properties

Sulfonation of Procyanidin Polymers: Evidence of Intramolecular Rearrangement and Aromatic Ring Substitution

Hide tanning with modified natural tannins

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