4-Bromo-2,5-dichlorophenol

The 2,3-dichloro-4-hydroxyphenyl derivative of aripiprazole was prepared to confirm the structure of a primary metabolite of aripiprazole (Scheme 21). The synthesis began with the protection of 4-bromo-2,3-dichlorophenol as its benzyl ether 71. Palladium-catalyzed amination of 71 with piperazine proceeded regioselectively in excellent yield. Alkylation of the piperazine 72 with 69 in the presence of K2CO3 and... 

Aripiprazole is used for the treatment of schizophrenia. The key intermediate, phenylpiperazine 56, was prepared by conventional methodology via a ring closure reaction from 2,3-dichlorophenol in six steps with an overall yield of 9%. Alternatively, phenyl-piperazine 56 was prepared via a Pd-catalyzed amination of benzyl protected 4-bromo-2,3-dichlorophenol 54 with piperazine. The coupling reactions proceeded regio-selectively to provide excellent yield of phenyl piperazine [136-140]. 

ACETIC ACID, SODIUM CHLORIDE, POTASSIUM CHLORIDE, XYLENE, DICHLOROPHENOL, BROMO-DICHLOROPHENOL, ACETIC ANHYDRIDE, SODIUM HYDROXIDE, methanol, TRICHLOROBENZENE Unknown 150 X ... 

DCDD can be synthesized by two methods. In the first method, 2-bromo-4-chlorophenol and potassium hydroxide are dissolved in methanol and evaporated to dryness. The residue is then mixed with bis(2-ethoxyethyl) ether, ethylene diacetate, and a copper catalyst and then heated, cooled, and eluted from a chromatographic column with chloroform. This residue is evaporated and then sublimed. DCDD can also be synthesized by heating the potassium salt of 2,4-dichlorophenol in the presence of copper powder in a vacuum sublimation apparatus (IARC 1977). 

Polyhalo aromatic compounds with different halogens may be selectively hydrogenolyzed, usually in the order of increasing ease of hydrogenolysis fluorine < chlorine < bromine < iodine. Thus, 4-bromo-2,6-dichlorophenol was selectively debrominated to give 2,6-dichlorophenol over palladium catalyst in benzene-cyclo-... 

SYNS 4-BROMO-2.5-DICHLOROPHENOL-0-ESTER mth 0,0-DIETHYL PHOSPHOROTHIOATE 0-(4-BROMO-... 

In 1953, recycling efforts for these waste isomers began, and thermal decomposition of these residues led to integration of several process steps (see figure). Thermal decomposition of the HCH isomers led to a 75% yield of 1,2,4-trichlorobenzene, which opened the process for production of 2,5-dichlorophenol and the corresponding bro-mination product. In addition to 2,5-dichloro-4-bromo-phenol production, the recycled trichlorobenzene was converted to 1,2,4,5-tetrachlorobenzene which could then be converted to 2,4,5-trichlorophenoxyacetic acid. 

The bromophos content of treated products rapidly decreases, after 10 days being less than 1 ppm, and after 20 days it can no longer be detected. Its most important metabolites injilant tissues are 4-bromo-2,5-dichlorophenol, bromoxon (41), formed by the exchange of thion-sulfur for oxygen, and mono-demethyl-bromophos (42), formed by partial demethylation (Stiasni et al., 1969). 

C6Ds02f Resorcinol (a form), 46B, 97 C6Dg02, Resorcinol ip form), 46B, 97 CeHClsO, Pentachlorophenol, 27, 903 CsH2Cla02, Tetrachlorohydroquinone, 27, 901 32B, CeH3BrN205, 2-Bromo-4,6-dinitrophenol, 41B, 129 C6H3CIN2O5, 2-Chloro-4,6-dinitrophenol, 41B, 130 C6H, C1N03, 2-Nitro-4-chlorophenol, 42B, 85 C6H Cl20, 2,3-Dichlorophenol, 42B, 85... 

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