2.3- Dihydro-2,3-dihydroxybenzoic

Enzyme systems have been isolated from Escherichia coli and Aerobacter aerogenes which convert chorismic acid to 2,3-dihydroxybenzoic acid. The enzyme from Aerobacter aerogenes requires magnesium and NAD" for activity and is strongly repressed by low concentrations of iron or cobalt . Omission of the pyridine nucleotide from the enzymic reaction mixture allowed the conversion of chorismic acid to an intermediate (44), which itself was converted to 2,3-dihydroxybenzoic acid on the subsequent addition of The intermediate compoimd was isolated and identified as 5,6-dihydrocyclohexa-l,3-diene-1-carboxylic acid (44) for which the trivial name 2,3-dihydro-2,3-dihydroxybenzoic acid was suggested The structure of the intermediate was established... 

Regioselective aminomethylation and subsequent cyclization of methyl 2,4-dihydroxybenzoate 517 was accomplished through a Mannich reaction with formaldehyde and primary amines in methanol to yield 3-substituted-3,4-dihydro-2/7-l,3-benzoxazine derivatives 518 (Equation 60). Simultaneous mixing of the reactants resulted in poor yields, but good yields were achieved by the pretreatment of paraformaldehye with a primary amine to form a Schiff base, followed by the addition of compound 517 <2001TL7273>. 

Benzoate 1,2-dioxygenase was shown to catalyze the conversion of benzoate to l,2-dihydro-l,2-dihydroxybenzoic acid (DHB) in the presence of NADH and oxygen by Reiner et al.205, 206). Yamaguchi et al.61> have demonstrated that the enzyme system consists of two components (A and B),both of which are required for benzoate 1,2-dioxygenase activity. Component A shows NADH-cytochrome c reductase activity and component B appears to be dioxygenase, thus the following reaction scheme is suggested [Eq. (25)]. 

Dihydroxybenzo b -l, 5-naphthyridin-10(5//)-one (66), easily made by fusion of 3-aminopicolinic acid with phloroglucinol, underwent oxidation to 4-oxo-1,4-dihydro-l,5-naphthyridine-2,3-dicarboxylic acid (67) [HNO3 (d. 1.5), 20°C, then 95°C, 40 min %, after separation from a byproduct].17... 

C19H40S methyl octadecyl sulfide 40289-98-3 635.00 68.067 2 31908 C20H14O2 9,10-dihydro-9,10-dihydroxybenzo(a)pyrene 24909-09-9 528.98 46.676 2... 

Aminosalicylic acid in assessment of reactive oxygen species formation by in vitro Fenton and ozonation reactions and by in vivo ozone-exposure experiments in rats revealed oxidation products as follows salicylic acid, by deamination 2,3-dihydro-xybenzoic acid and 2,5-dihydroxybenzoic acid, from radical or enzymatic hydroxylation 5-amino-2 - hydroxy-N,W-bis(3 - carboxy- 4- hydroxyphenyl)-1,4-benzoquinonediimine, a condensation product of oxidised 5-aminosalicylic acid and 5-amino-2,3,4,6-tetrahydroxybenzoic acid, attributed to hydroxyl radical attack without deamination, identified by high-pressure liquid chromatography electrochemical detector system analysis and by gas chromatography-mass spectrometry analysis of trimethyl silyl derivatives (Kumarathasan et al. 2001). 

Dihydro-l,5-dimethyl-3-oxo-2-phenyl-lH-pyrazol-4-yl)azo]-2,4-dihydroxybenzoic acid, 9CI... 

Dihydro-6,7-dimethoxy-4-methyl-3-oxo-2-quinoxalinecarbonyl azide, in D-00379 5-[(2,3-Dihydro-1,5-dimethyl-3-oxo-2-phenyl-1 //-pyrazol-4-yl)azo]-2,4-dihydroxybenzoic acid, D-00381... 

---