6563-36-6

Upstream product

• 186581-53-3 diazomethane 
• 480-18-2 taxifolin 
• 51079-25-5 (2R,3S)-(+)-catechin 3',4',5,7-tetramethyl ether 
• 77-78-1 dimethyl sulfate 
• 154-23-4 catechin 
• 27297-45-6 (2R,3R)-(+)-dihydroquercetin-3-β-D-glucopyranoside 
• 29838-67-3 astilbin 

Downstream Products

• 13650-85-6 (2R,3R)-3-O-acetyl-5,7,3',4'-tetra-O-methyltaxifolin 
• 855-97-0 2-(3,4-dimethoxyphenyl)-5,7-dimethoxy-4H-chromen-4-one 
• 74628-43-6 (2S)-5,7,3',4'-tetramethoxyflavanone 
• 35499-74-2 3’,4’,5,7-tetra-O-methyl-4β-hydroxycatechin 
• 87303-89-7 (+)-(2R,3S,4R)-3,4-dihydroxy-5,7,3',4'-tetramethoxyflavan 
• 737758-21-3 3',4',5,7-tetramethyldihydroquercetin-3-yl neopentylene phosphite 
• 13650-85-6 (+/-)-taxifolin 3-acetyl-5,7,3',4'-tetramethyl ether 
• 94757-83-2 2-(3,4-dimethoxy-benzyl)-2,4,6-trimethoxy-benzofuran-3-one 
• 18207-63-1 2-hydroxy-4,6-dimethoxy-2-veratryl-benzofuran-3-one 
• 1244-78-6 2-(3,4-dimethoxyphenyl)-3-hydroxy-5,7-dimethoxy-4H-4-chromenone 
• 25121-65-7 (+/-)-3t-Acetoxy-2r-(3,4-dimethoxy-phenyl)-5,7-dimethoxy-chroman 
• 14613-67-3 (2R^*,3S^*,4S^*)-5,7,3',4'-tetramethoxyflavan-3,4-diol 
• 14613-67-3 (2R^*,3S^*,4R^*)-5,7,3',4'-tetramethoxyflavan-3,4-diol 
• 14613-67-3 2r-(3,4-Dimethoxy-phenyl)-5,7-dimethoxy-chroman-3t,4ξ-diol 

Relevant academic research and scientific papers

3-O-carbamoyl-5,7,20-O-trimethylsilybins: Synthesis and preliminary antiproliferative evaluation

To search for novel androgen receptor (AR) modulators for the potential treatment of castration-resistant prostate cancer (CRPC), naturally occurring silibinin was sought after as a lead compound because it possesses a moderate potency towards AR-positive prostate cancer cells and its chemical scaffold is dissimilar to all currently marketed AR antagonists. On the basis of the structure–activity relationships that we have explored, this study aims to incorporate carbamoyl groups to the alcoholic hydroxyl groups of silibinin to improve its capability in selectively suppressing AR-positive prostate cancer cell proliferation together with water solubility. To this end, a feasible approach was developed to regioselectively introduce a carbamoyl group to the secondary alcoholic hydroxyl group at C-3 without causing the undesired oxidation at C2–C3, providing an avenue for achieving 3-O-carbamoyl-5,7,20-O-trimethylsilybins. The application of the synthetic method can be extended to the synthesis of 3-O-carbamoyl-3′,4′,5,7-O-tetramethyltaxifolins. The antiproliferative potency of 5,7,20-O-trimethylsilybin and its nine 3-carbamoyl derivatives were assessed in an AR-positive LNCaP prostate cancer cell line and two AR-null prostate cancer cell lines (PC-3 and DU145). Our preliminary bioassay data imply that 5,7,20-O-trimethylsilybin and four 3-O-carbamoyl-5,7,20-O-trimethylsilybins emerge as very promising lead compounds due to the fact that they can selectively suppress AR-positive LNCaP cell proliferation. The IC50 values of these five 5,7,20-O-trimethylsilybins against the LNCaP cells fall into the range of 0.11–0.83 μM, which exhibit up to 660 times greater in vitro antiproliferative potency than silibinin. Our findings suggest that carbamoylated 5,7,20-O-trimethylsilybins could serve as a natural product-based scaffold for new antiandrogens for lethal castration-resistant prostate cancer.

Exciton chirality method in vibrational circular dichroism

The interaction of two IR chromophores yields a strong vibrational circular dichroism couplet whose sign reflects the absolute configuration of the molecule. We present a method to determine absolute configuration of a chiral molecule based on this couplet without need of theoretical calculation. Not only can this method analyze various molecules whose absolute configuration is difficult to determine by other spectroscopic methods, but also it can significantly enhance VCD signals.

Chemoselective C-4 aerobic oxidation of catechin derivatives catalyzed by the trametes villosa laccase/1-hydroxybenzotriazole system: Synthetic and mechanistic aspects

Catechin derivatives were oxidized in air in the presence of the Trametes villosa laccase/1-hydroxybenzotriazole (HBT) system in buffered water/1,4-dioxane as reactionmedium. The oxidation products, flavan- 3,4-diols and the corresponding C-4 ketones, are

Inhibitory compound of tyrosinase activity from the sprout of Polygonum hydropiper L. (Benitade)

A tyrosinase inhibitor was isolated from the sprout of Polygonum hydropiper L. (Benitade) by activity-guided fractionation and identified as (2R,3R)-(+)-taxifolin (1) by spectroscopic means. Compound 1 inhibited 70% of tyrosinase activity at a concentration of 0.50mM. ID50 (50% inhibition dose) value of compound 1 was 0.24mM. As compared with tyrosinase inhibitor known cosmetic agent such as arbutin and kojic acid, compound 1 was more inhibited than the former and showed inhibitory effect equal to that of the latter. To study the inhibitory effect of (2R,3R)-(+)-taxifolin derivatives against tyrosinase activity, 3,7,3′,4′-taxifolin tetraacetate (2) and 5,7,3′,4′-taxifolin teramethyl ether (3) were also assayed together with compound 1.

Stereoselective oxidation at C-4 of flavans by the endophytic fungus Diaporthe sp. isolated from a tea plant

The microbial transformation of five flavans (1-5) by endophytic fungi isolated from the tea plant Camellia sinensis was investigated. It was found that the endophytic filamentous fungus Diaporthe sp. oxidized stereoselectively at C-4 position of (+)-catechin (1) and (-)-epicatechin (2) to give the correspondent 3,4-cis-dihydroxyflavan derivatives (6, 10), respectively. (-)-Epicatechin 3-O-gallate (3) and (-)-epigallocatechin 3-O-gallate (4) were also oxidized by the fungus into 3,4-dihydroxyflavan derivatives (10, 12) via (-)-epicatechin (2) and (-)-epigallocatechin (11), respectively. Meanwhile, (-)-gallocatechin 3-O-gallate (5), (-)-catechin (ent-1) and (+)-epicatechin (ent-2), which possess a 2S-phenyl substitution, resisted the biotransformation.

Antinociceptive and anti-oedematogenic properties of astilbin, taxifolin and some related compounds

Astilbin (3-0-α-1-rhamnosyl-(2R,3R)-dihydroquercetin), the major constituent isolated from Hymeneae martiana and some derivatives obtained by structural modification, such as taxifolin and two related compounds, were evaluated as analgesics by using both writhing test and formalin test in mice. Their anti-oedematogenic actions were also analysed against paw oedema caused by carrageenan, dextran and bradykinin in rat. The results indicated that some compounds, such as taxifolin (2) and its tetramethylated derivative (4) exhibited potent and dose-dependent antinociceptive action against acetic acid-induced abdominal constriction when administered intraperitoneally or orally. They were more potent than acetylsalicylic acid and paracetamol (acetaminophen), two standard drugs used for comparison. Compounds 2 and 4 were also more potent than these drugs in attenuating to the second phase of the formalin-induced licking. Moreover, both compounds showed significant anti-oedematogenic effect, inhibiting the paw oedema formation induced by dextran. In contrast pentaacetylated taxifolin (3) was capable of inhibiting the paw oedema induced by bradykinin.

REGIO- AND STEREOSELECTIVE OXYGENATION OF FLAVAN-3-OL-, 4-ARYLFLAVAN-3-OL-, AND BIFLAVANOID-DERIVATIVES WITH POTASSIUM PERSULPHATE

The phenolic methyl ethers of flavan-3-ols, 4-arylflavan-3-ols, and (-)-fisetinidol-(4,8)-(+)-catechin biflavanoids are susceptible to regio- and stereoselective hydroxylation at C-4 in moderate to high yields with potassium persulphate/cupric sulphate in aqueous acetonitrile.The resultant 4-functionalized analogues are of both synthetic and degradative significance in condensed tannin chemistry.

TAXIFOLIN 3-ARABINOSIDE FROM TRACHELOSPERMUM JASMINOIDES VAR. PUBESCENS

Key Word Index-Trachelospermum jasminoines var. pubescens; Apocynaceae; dihydroflavonol; taxifolin 3-arabinoside; taxifolin 3-glucoside; EIMS; structural elucidation; biologically active substance.A new dihydroflavonol glycoside, taxifolin 3-arabinoside, together with knonw substances: taxifolin 3-glucoside, quercetin 3-arabinoside, taxifolin and chlorogenic acid were identified from the leaves of Trachelospermum jasminoides var. pubescens.Structural elucidation was carried out by comparison of mass spectra with those of their methylated and acetylated derivatives.Taxifolin 3-glycosides were found to be Aphanomyces cochlioides zoospore attractants.

LEUCOCYANIDIN: SYNTHESIS AND PROPERTIES OF (2R,3S,4R)-(+)-3,4,5,7,3',4'-HEXAHYDROXYFLAVAN

An isomer of leucocyanidin, (2R,3S,4R)-(+)-3,4,5,7,3',4'-hexahydroxyflavan has been synthesized from (+)-taxifolin, isolated in its phenolic form, and characterized by 1H and 13C NMR, and formation of the 5,7,3',4'-tetramethyl ether.Leucocyanidin readily polymerizes in acid solution to form a procyanidin polymer of high MW. - Key Word Index: Leucocyanidin; flavan-3,4-diols; synthesis; polymerization; phytochemical significance.

Photochemical Deoxygenation of an α-Ketol: The Dihydroflavonol-Flavanone Conversion

Irradiation of optically pure 2,3-trans-3-hydroxyflavanones in anhydrous ethyl acetate leads directly to free phenolic flavanone analogues with complete retention of configuration at C(2).Similarly their methyl ethers give the corresponding flavanones and flavones.The reaction represents the photochemical equivalent of a reduction under Clemmensen conditions.