Chloro-p-benzoquinone

The antibacterial agent sulfamethoxazole produced chlorinated and nonchlorinated DBFs when reacted with chlorine [91]. A ring-chlorinated product was formed via halogenation of the aniline moiety at sub-stoichiometiic concentrations of chlorine. 3-Amino-5-methylisoxazole, sulfate, and A-chloro-p-benzoquinone imine were formed via rupture of the sulfamethoxazole sulfonamide moiety at stoichiometric excess of chlorine. 

Diazo 2-bromo-6-chloro-p benzoquinone [ called 6-Chlor-2-brom-p-chinon-diazid-(4) or 6-Chlor-2 -brom-4-diazo-phenol in Ger], yel-red ndls (from hot eth, benz or chlf), explodes violently on heating to 15 0° v sol in hot ale si sol in hot eth or chlf insol in w was obtd by addn of bromine water to an aq soln of 4-diaZo-6-chloro -phenol-2 sulfonic acid(Refs 2 3)... 

GC-MS and HPLC analyses of electrolyzed solutions allowed the detection of aromatic intermediates such as p-benzoquinone and nitrobenzene for aniline, 4-chlorocatechol for 4-chlorophenol, 4-chlorophenol, 4-chlorocatechol, hydroquinone, and p-benzoquinone for 4-CPA, 4-chloro-o-cresol, mehylhy-droquinone, and methyl-p-benzoquinone for MCPA, 2,4-dichlorophenol, 4,6-dichlororesorcinol, chlorohydroquinone, and chloro-p-benzoquinone for 2,4-D, and 2,4,5-trichloro-phenol, 2,5-dichlorohydroquinone, 4,6-dichlororesorcinol, and 2,5-dihydroxy-p-benzoquinone for 2,4,5-T. In general, these by-products persisted in solution while the initial pollutant was degraded. 

Figure 3. pH dependence of for the electron transfer from cw-[Et2Co(bpy)2] to p-benzoqui-none derivatives in H20-EtOH (5 1 v/v) at 298 K 2,6-dichloro-p-benzoquinone (O) 2,5-dichloro-p-benzoquinone ( ) chloro-p-benzoquinone (A) p-benzoquinone (A) methyl-p-benzoquinone ( ) and 2,6-dimethyl-p-benzoquinone ( ). 

Potassium chromate, K2Cr04, is used very rarely. It converts hydra-zomethane into azomethane [613]. In the presence of hexamethylphos-phoramide and crown ether, it transforms allylic and benzylic bromides into a,p-unsaturated aldehydes [614], and in the presence of dilute sulfuric acid, it oxidizes chlorohydroquinone to chloro-p-benzoquinone [615]. 

Such oxidations are especially easy, if electron-releasing groups such as hydroxyls or amino groups are located in para or ortho positions with respect to the amino groups. 3-Chloro-4-aminophenol stirred with sodium dichromate and sulfuric acid at a temperature below 35 °C gives a 58-63% yield of chloro-p-benzoquinone after the reaction mixture is allowed to stand at room temperature for 1 h [6J7]. Aminothymol is converted into thymoquinone on warming for 30 min with dilute sulfuric acid and sodium nitrite (equation 530) [451],... 

Dichloro-5,6-dicyano-p-benzoquinone, 46B, 112 a-2-Chloro-p benzoquinone-4-oxime acetate, 26, 709 /3-2-Chloro p-benzoquinone 4-oxime acetate, 26, 709 a 5 (2 -Chloroethoxy)-o-benzoquinone-2-oxime (anti... 

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