4-hydroxybenzoate

Oxepin has also been converted photochemically to phenol in 74% yield. This reaction occurs under irradiation conditions by which benzene oxide is excited to a triplet state, e.g. by irradiation in acetone as solvent.207 A rare example for a nucleophilic catalysis of the aromatization of an oxepin/benzene oxide to a phenol has been reported for /err-butyl oxepin-4-carboxylate which undergoes a rearrangement reaction in the presence of trimethylamine to give a mixture of /m-butyl 3-hydroxybenzoate (94%) and 4-hydroxybenzoate (6%).243... 

Industrial electrochemical reduction processes exist for the conversion of 3-hydroxybenzoic acid to 3-hydroxybenzyl alcohol and 4-nitroben-zoic acid to 4-aminobenzoic acid. How may these processes be carried out Compare these processes in terms of the Principles of Green Chemistry with alternative non-electrochemical methods. 

Gao X, CL Tan, CC Yeo, CL P (2005) Molecular and biochemical characterization of the x/ D-encoded 3-hydroxybenzoate 6 hydroxylase involved in the degradation of 2,5-xylenol via the gentisate pathway in Pseudomonas alcaligenes NCIMB 9S61. J Bacterial 187 7696-7702. 

The gentisate pathway may plausibly be involved in the degradation of benzoate by a denitrifying strain of Pseudomonas sp. in which the initial reaction is the formation of 3-hydroxybenzoate (Altenschmidt et al. 1993). 

In the degradation of 3-hydroxybenzoate, divergent pathways are used by different groups of pseudomonads ... 

Unusual reactions have been encountered in the aerobic degradations carried out by Azoarcus evan-sii and Geobacillus stearothermophilus (Zaar et al. 2001). The anaerobic degradation of benzoate by Azoarcus evansii (Ebenau-Jehle et al. 2003) and Thauera aromatica (Domer and Boll 2002), and of 3-hydroxybenzoate by Th. aromatica (Laempe et al. 2001) is discussed later. 

The fermentation of 3-hydroxybenzoate by Sporotomaculum hydroxybenzoicum produces acetate, butyrate, and CO2, with benzoate as a transient intermediate (Brauman et al. 1998). However, although the degradation of 3-hydroxybenzoate by Thauera aromatica begins with the formation of the CoA-ester, this is followed by the reduction of the ring with retention of the original hydroxyl group (Laempe et al. 2001). 

Brauman A, JA Muller, J-L Garcia, A Brine, B Schink (1998) Eermentative degradation nof 3-hydroxybenzoate in pure culture by a novel strictly anaerobic bacterium, Sporotomaculum hydroxybenzoicum gen. nov., sp. nov. Int J Syst Bacterial 48 215-221. 

Crawford RL (1975a) Degradation of 3-hydroxybenzoate by bacteria of the genus Bacillus. Appl Microbiol 30 439-444. 

Jones DCN, RA Cooper (1990) Catabolism of 3-hydroxybenzoate by the gentisate pathway in Klebsiella pneumoniae M5al. Arch Microbiol 154 489-495. 

Laempe D, M Jahn, K Breese, H Schagger, G Euchs (2001) Anaerobic metabolism of 3-hydroxybenzoate by the denitrifying bacterium Thauera aromatica. J Bacteriol 183 968-979. 

Muller JA, B Schink (2000) Initial steps in the fermentation of 3-hydroxybenzoate by Sporotomaculum hydroxybenzoicum. Arch Microbiol 173 288-295. 

Bonting CFC, S Schneider, G Schmidtberg, G Fuchs (1995) Anaerobic degradation of m-cresol via methyl oxidation to 3-hydroxybenzoate by a denitrifying bacterium. Arch Microbiol 164 63-69. 

Incubation Conditions pmoles 3-hydroxybenzo(a)pyrene formed/min/nmol cytochrome P-448 % Maximum Activity... 

Biological. Benzoic acid may degrade to catechol if it is the central metabolite whereas, if protocatechuic acid (3,4-dihydroxybenzoic acid) is the central metabolite, the precursor is 3-hydroxybenzoic acid (Chapman, 1972). Other compounds identified following degradation of benzoic acid to catechol include cis,c/5-muconic acid, (+)-muconolactone, 3-oxoadipate enol lactone, and 3-oxoadipate (quoted, Verschueren, 1983). Pure microbial cultures hydroxylated benzoic acid to 3,4-dihydroxybenzoic acid, 2- and 4-hydroxybenzoic acid (Smith and Rosazza, 1974). In activated sludge, 65.5% mineralized to carbon dioxide after 5 d (Freitag et al., 1985). 

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