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Pyrogallol is an organic compound with the formula C 6 H 3 (OH) 3. It is a water-soluble, white solid although samples are typically brownish because of its sensitivity toward oxygen. [ 3 ] It is one of three isomers of benzenetriols .
It is a metabolite in the degradation of 3,4,5-trihydroxybenzoate (gallic acid) by Eubacterium oxidoreducens. [ 1 ] The enzyme pyrogallol hydroxytransferase uses 1,2,3,5-tetrahydroxybenzene and 1,2,3-trihydroxybenzene ( pyrogallol ), whereas its two products are 1,3,5-trihydroxybenzene ( phloroglucinol ) and 1,2,3,5-tetrahydroxybenzene.
Its bulk properties partly result from the interaction of its component atoms, oxygen and hydrogen, with atoms of nearby water molecules. Hydrogen atoms are covalently bonded to oxygen in a water molecule but also have an additional attraction (about 23.3 kJ·mol −1 per hydrogen atom) to an adjacent oxygen atom in a separate molecule. [2]
This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O 2 as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases). The oxygen incorporated need not be derived from O 2. The systematic name of this enzyme class is 1,2,3-trihydroxybenzene:oxygen 1,2-oxidoreductase ...
Syringol is the organic compound with the formula HO(CH 3 O) 2 C 6 H 3. The molecule is a phenol, with methoxy groups in the flanking (2 and 6) positions. It is the symmetrically dimethylated derivative of pyrogallol. It is a colorless solid, although typical samples are brown owing to air-oxidized impurities.
This test relies on reaction of the furfural with phloroglucinol to produce a colored compound with high molar absorptivity. [26] A solution of hydrochloric acid and phloroglucinol is also used for the detection of lignin (Wiesner test). A brilliant red color develops, owing to the presence of coniferaldehyde groups in the lignin. [27]
A hydrolysable tannin or pyrogallol-type tannin is a type of tannin that, on heating with hydrochloric or sulfuric acids, yields gallic or ellagic acids. [ 1 ] At the center of a hydrolysable tannin molecule , there is a carbohydrate (usually D-glucose but also cyclitols like quinic or shikimic acids ).
The Dakin oxidation can occur in mild acidic conditions as well, with a mechanism analogous to the base-catalyzed mechanism. In methanol, hydrogen peroxide, and catalytic sulfuric acid, the carbonyl oxygen is protonated (14), after which hydrogen peroxide adds as a nucleophile to the carbonyl carbon, forming a tetrahedral intermediate (15).