Carboxylic Catechin

Carboxylic acids, ammonium salts Catechins p-Toluenesulfonic acid (20% in Fluorescent spots under long-wave 50... 

Brevifolin carboxylic acid (phenolic ketone) Capillarisin (flavonoid) 2-Carbethoxy-5,7-dihydroxy-4 -methoxy-isoflavone (isoflavone) (+)-Catechin (= Catechinic acid Catechuic acid (+)-Cyanidanol (27 ,3i)-5,7,3, 4 -Tetrahydroxyflavan-3-ol) (flavan-3-ol)... 

TMS production involves one specific functional group (-OH, -COOH, =NH, -NH2, or -SH), which loses an activated hydrogen and is replaced by a trimethylsilyl group (Proestos et ah, 2006). To achieve silylation, some authors have used BSTFA (N,0-hA(trimethyl-silyl)trifluoroacetamide) and TMCS (trimethylchlorosilane) successfully in several matrices (e.g. aromatic plants, cranberry fixiit) (Zuo et ah, 2002 Proestos et ah, 2006). Using silylated derivatives is advantageous for several reasons phenols and carboxylic acids are prone to silylation, these compounds can be derivatized in the same part of the process, and the minor products do not impede analysis and are well documented (Little, 1999 Stalikas, 2008). A two-step methylation procedure was used to analyze catechins and tannins in plant extracts. The first step used trimethylsilyl diazomethane (TMS-diazomethane) to pre-methylate the sample, and the second step used thermally assisted hydrolysis and methylation (THM). The pre-methylation step with TMS-diazomethane stabilized the dimer molecule m/z 540) by minimizing isomerization and reducing reactivity. (Shadkami et ah, 2009). 

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