2347-40-2

Upstream product

• 99-50-3 3,4-Dihydroxybenzoic acid 
• 999-97-3 1,1,1,3,3,3-hexamethyl-disilazane 
• 10416-59-8 N,O-bis-(trimethylsilyl)-acetamide 
• 25561-30-2 N,O-Bis(trimethylsilyl)trifluoroacetamide 
• 117-39-5 quercetol 

Relevant academic research and scientific papers

The influence of the host-guest interaction on the oxidation of natural flavonoid dyes

The influence of the molecular cavity protection on degradation processes of bioorganic compounds quercetin and luteolin used as the original dyes in old tapestries was studied. The degradation processes were studied by electrochemical methods in aqueous media. The products of the exhaustive electrolysis were separated and identified by GC-MS analysis. Cyclic voltammetry characteristics indicate that the inclusion complex is formed. The inclusion affects the redox potentials of both oxidation waves related to the different dissociation forms of the flavonoid molecule. It was shown that decomposition products formed by the oxidation of quercetin are stabilized in the cavity of β-cyclodextrin, including the main oxidation product 2(3',4'- dihydroxybenzoyl)-2,4,6-trihydroxybenzofuran-3(2H)-one. The formation of the 1:1 inclusion complex of luteolin with β-cyclodextrin is supported by the enhancement of fluorescence intensity. In the case of quercetin, a decrease of fluorescence intensity occurs when 1:1 inclusion complex with β-cyclodextrin is formed.

Partition coefficients of ketones, phenols, aliphatic and aromatic acids, and esters in n-hexane/nitromethane

Liquid-liquid partition is used in sample preparation and in countercurrent and liquid-liquid chromatographic separations. Partition coefficients are widely used in toxicology, environmental, and analytical chemistry. The K hn determination procedure for the n-hexane/ nitromethane system was optimized and partition coefficients for 99 ketones, esters and trimethylsilyl derivatives of phenols, aliphatic and aromatic acids were determined. For 130 compounds, Khn values were predicted using mathematical relationships between Khn and other physicochemical and structural parameters. Versita Sp. z o.o.

Characterization of phenolic compounds in rooibos tea

Polyphenols present in rooibos, a popular herbal tea from Aspalathus linearis, were isolated in two steps. First, phenolic ingredients were separated by multilayer countercurrent chromatography (MLCCC). Preparative high-performance liquid chromatography (HPLC) was then applied to obtain pure flavonoids. The purity and identity of isolated compounds was confirmed by different NMR experiments, HPLC-diode array detector (DAD), or gas chromatography-mass spectrometry (GC-MS) analysis. This strategy proved to be valid to isolate material in up to gram quantities and to verify known and previously not published polyphenol structures. In addition the chemistry of dihydrochalcones and related intermediates was studied. The dihydrochalcone aspalathin was oxidized to the corresponding flavanone-C-glycosides ((R)/(S)-eriodictyol-6-C-β-D-glucopyranoside and (R)/(S)-eriodictyol-8-C- β-D-glucopyranoside). Flavanone-6-C-β-D-glucopyranosides were further degraded to flavones isoorientin and orientin.

ASSIGNMENT OF 29Si NMR LINES AND DETERMINATION OF 29Si-13C COUPLING CONSTANTS IN PERTRIMETHYLSILYLATED LIGNIN-RELATED PHENOL-CARBOXYLIC ACIDS BY SELECTIVE HETERONUCLEAR INADEQUATE METHOD

Selective heteronuclear (Si-C) INADEQUATE method has been successfully used to assign all 29Si chemical shifts in six pertrimethylsilylated lignin model compounds.Empirical assignment of the lines in the region δ=23-25 to trimethylsilyl esters of carboxyl