12798-59-3

Upstream product

• 22970-70-3 (2R,3R,4S)-2,3-cis-3,4-trans-3',4',5,7-tetramethoxyflavan-3,4-diol 
• 154-23-4 catechin 
• 86849-67-4 (2R,3S,4S)-2,3-cis-3,4-trans-3,3',4',5,7-pentahydroxy-4-phenylthioflavan 
• 88191-48-4 5,7,3',4'-tetrahydroxyflavan-3-ol hydrate 
• 61540-96-3 C₁₅H₁₃O₆⁽¹⁺⁾ 
• 480-17-1 2,3-trans-flavan-3,4-diol 
• 490-46-0 (2R,3R)-2-(3,4-dihydroxyphenyl)-3,4-dihydro-1[2H]-benzopyran-3,5,7-triol 
• 101401-64-3 epicatechin-(4β->6)-epicatechin-(4β->6)-epicatechin 
• 100-53-8 phenylmethanethiol 
• 114637-80-8 C₆₀H₄₈O₂₄ 
• 480-18-2 taxifolin 
• 480-17-1 (+)-leucocyanidin 
• 1438268-60-0 C₉₃H₁₅⁽²⁾H₆₃BrClO₁₂ 

Downstream Products

• 65052-97-3 Acetic acid (2R,3R,4R,2'R,3'S)-5,7,3',5',7'-pentaacetoxy-2,2'-bis-(3,4-diacetoxy-phenyl)-3,4,3',4'-tetrahydro-2H,2'H-[4,6']bichromenyl-3-yl ester 
• 105487-44-3 (2R,3S,4S,2'R,3'R)-2,2'-Bis-(3,4-dimethoxy-phenyl)-5,7,5',7'-tetramethoxy-3,4,3',4'-tetrahydro-2H,2'H-[4,6']bichromenyl-3,3'-diol 
• 37064-35-0 4β-benzylthioepicatechin 
• 128837-34-3 4α-Benzylthioepicatechin 
• 154-23-4 catechin 
• 13306-05-3 cyanidin 

Relevant academic research and scientific papers

Regioselective synthesis of procyanidin B6, A 4-6-condensed (+)-catechin dimer, by intramolecular condensation

Proanthocyanidins, also known as condensed tannins or oligomeric flavonoids, are found in many edible plants and exhibit interesting biological activities. Herein, we report a new, simple method for the stereoselective synthesis of procyanidin B6, a (+)-catechin-(4-6)-(+)-catechin dimer, by Lewis acid-catalyzed intramolecular condensation. The 5-O-t-butyldimethylsilyl (TBDMS) group of 5,7,34-tetra-O-TBDMS-(+)-catechin was regioselectively removed using trifluoroacetic acid, leading to the “regio-controlled” synthesis of procyanidin B6. The 5-hydroxyl group of the 7,3,4-tri-O-TBDMS-(+)-catechin nucleophile and the 3-hydroxyl group of 5,7,3,4-tetra-O-benzylated-(+)-catechin electrophile were connected with an azelaic acid. The subsequent SnCl4-catalyzed intramolecular condensation proceeded smoothly to give the 4-6-condensed catechin dimer. This is the first report on the complete regioselective synthesis of a 4-6-connected oligomer without modifying the 8-position.

Molecular Interaction between Salivary Proteins and Food Tannins

Polyphenols interaction with salivary proteins (SP) has been related with organoleptic features such as astringency. The aim of this work was to study the interaction between some human SP and tannins through two spectroscopic techniques, fluorescence quenching, and saturation transfer difference-nuclear magnetic resonance (STD-NMR). Generally, the results showed a significant interaction between SP and both condensed tannins and ellagitannins. Herein, STD-NMR proved to be a useful tool to map tannins' epitopes of binding, while fluorescence quenching allowed one to discriminate binding affinities. Ellagitannins showed the greatest binding constants values (KSV from 20.1 to 94.1 mM-1 KA from 0.7 to 8.3 mM-1) in comparison with procyanidins (KSV from 5.4 to 40.0 mM-1 KA from 1.1 to 2.7 mM-1). In fact, punicalagin was the tannin that demonstrated the highest affinity for all three SP. Regarding SP, P-B peptide was the one with higher affinity for ellagitannins. On the other hand, cystatins showed in general the lower KSV and KA values. In the case of condensed tannins, statherin was the SP with the highest affinity, contrasting with the other two SP. Altogether, these results are evidence that the distinct SP present in the oral cavity have different abilities to interact with food tannins class.

A seco-catechin cyclization approach to 4→6-linked catechin dimers

A viable route has been developed for the selective synthesis of the 4→6-linked catechin dimers, scarcely accessible from Nature and/or through synthesis. An acyclic nucleophilic catechin precursor (seco-catechin) was used for the regioselective union with an electrophilic catechin unit, and subsequent pyran cyclization gave the desired 4→6-linked dimers, i.e., procyanidin B6 and catechin-(4α→6)-gallocatechin. This journal is

First regiocontrolled synthesis of procyanidin B6, a catechin dimer with rare connectivity: A halo-capping strategy for formation of 4,6-interflavan bonds

The first regiocontrolled synthesis of procyanidin B6, a dimer with a rare 4,6-interflavan linkage, is described. Regioselective linking was achieved by the halo-capping strategy followed by removal of all the benzyl protecting groups and the halo-caps by one-pot hydrogenolysis.

Preparation of dimeric procyanidins B1, B2, B5, and B7 from a polymeric procyanidin fraction of black chokeberry (Aronia melanocarpa)

A semisynthetic approach has been used for the preparative formation of dimeric procyanidins B1, B2, B5, and B7. As starting material for the semisynthesis, polymeric procyanidins from black chokeberry were applied. These polymers were found to consist almost exclusively of (-)-epicatechin units. Under acidic conditions the interflavanoid linkages of the polymeric procyanidins are cleaved and the liberated (-)-epicatechin can react with nucleophiles, such as (+)-catechin or (-)-epicatechin. In this way, the polymeric procyanidins are degraded while dimeric procyanidins are formed. During this reaction only dimeric procyanidins are formed that contain (-)-epicatechin in the upper unit, that is, B1 [(-)-EC-4β→8-(+)-C)], B2 [(-)-EC-4β→8-(-)-EC], B5 [(-)-EC-4β→6-(-)-EC], and B7 [(-)-EC-4β→6-(+)-C]. The reaction mixtures of the semisynthesis can be successfully fractionated with high-speed countercurrent chromatography (HSCCC), and it is possible to isolate pure procyanidins B1, B2, B5, and B7 on a preparative scale.

Extensive High-Resolution Reverse 2D NMR Analysis for the Structural Elucidation of Procyanidin Oligomers

The structures of the procyanidin dimers catechin-(4α-8)-catechin and catechin-(4α-6)-catechin were proved by spectroscopic means.To distinguish between the two possible interflavonoid linkages, it is necessary to assign all the quaternary aromatic carbon signals.How these assignments can be made through two-dimensional NMR spectroscopy is described. - Keywords: 2D NMR 1H NMR 13C NMR Structural analysis Proanthocyanidins Catechin dimers Tannins

Tannins and Related Compounds. LX. Isolation and Characterization of Proanthocyanidins with a Doubly-Linked Unit from Vaccinium vitis-idaea L.

New proanthocyanidin trimers (14 and 15) and tetramers (16 and 17) have been isolated from the whole body of Vaccinium vitis-idaea L. (Ericaceae).The structures of these proanthocyanidins were established by thiolytic degradation and by analyses of the proton and carbon-13 nuclear magnetic resonance spectra.In addition, the presence of (-)-epicatechin (1), (+)-catechin (2), (-)-epigallocatechin (3), (+)-gallocatechin (4), procyanidins B-1 (5), B-3 (6), A-1 (8) and A-2 (9), and cinnamtannins B1 (10), D1 (11), B2 (12) and D2 (13) in this plant was demonstrared.Keywords - Vaccinium vitis-idaea; Ericaceae; doubly-bonded proanthocyanidin; procyanidin; condensed tannin; flavan-3-ol; thiolytic degradation

SYNTHESIS AND CHARACTERIZATION OF PROCYANIDIN DIMERS AS THEIR PERACETATES AND OCTAMETHYL ETHER DIACETATES

Key Word Index - Biomimetic synthesis; procyanidins B1-B8; 3,4-cis-biflavanoid; all--bi--(+)-catechin; 1H NMR parameters. Condensation of (2R,3S,4R or S)-leucocyanidin or the 5,7,3',4'-tetramethyl ether of (2R,3R,4S)-leucocyanidin with flavan-3-ols yielded dimeric flavanoids which were converted to their octamethyl ether diacetates, or the deca-acetates for the 2,3-trans-procyanidin series.Comparison is made of the 1H NMR spectra of the deca-acetate and octamethyl ether diacetate derivatives which lead to useful diagnostic shift parameters characteristic of their structures.Condensation afforded a novel biflavanoid with a 3,4-cis-configuration and a triflavanoid of 'mixed' stereochemistry.

Synthesis of Condensed Tannins. Part 13. The First 2,3-trans-3,4-cis-Procyanidins: Sequence of Units in a 'Trimer' of Mixed Stereochemistry

The condensation of (+)-leucocyanidin with (-)-epicatechin initiates a succession of substitutions leading mainly to the introduction of -2,3-trans-3,4-procyanidin units, but also to the incorporation of 'terminal' moieties which possess the hitherto unique 3,4-cis-procyanidin configuration.The bonding patterns in the products, and also the sequence of units in one of the 'trimers' of mixed stereochemistry, are resolved by (1)H n.m.r. spectroscopy through selective use of solvents at elevated temperatures.