4-chlorophenylacetic acid

Chlorophenylacetic acid [1878-65-5] M 170.6, m 74°, pK 4.11. Crystd from EtOH/water, or as needles from C6H6 or H2O (charcoal). The acid chloride (prepared by boiling with SOCI2) has b 127-129°/15mm. [Dippy and Williams J Chem Soc 161 1934 Misra and Shukla J Indian Chem Soc 28 480 1951.]... 

Chlorophenylacetic acid has been prepared from mandeloni-trile and hydrochloric acid in a sealed tube, from mandelic acid and hydrochloric acid in a sealed tube/ from a-nitrostyrene and hydrochloric acid in a sealed tube, from phenylglycine, hydrochloric acid, and sodium nitrite, from mandelic acid and phosphorus pentachloride (to give the acid chloride which is then hydrolyzed), and, in poor yield, from mandelic acid and thionyl chloride. In the method described, ethyl mandelate is prepared according to Fischer and Speier. The conversion to the chloroester and the acid hydrolysis step are modifications of a preparation described by McKenzie and Barrow. ... 

DKR of esters bearing an electron-withdrawing group at the ot-carbon can be performed easily under mild reaction conditions due to the low pKa of the oc-proton. Tsai et al. have reported an efficient DKR of rac-2,2,2-trifluoroethyl ot-chorophenyl acetate in water-saturated isooctane [40]. They used lipase MY from C. rugosa for the KR and trioctylamine as the base for racemization. (R)-chlorophenylacetic acid was obtained in 93% yield and 89.5% ee (Figure 4.15). 

The Hammett equation is the best-known and most widely studied of the various linear free energy relations for correlating reaction rate and equilibrium constant data. It was first proposed to correlate the rate constants and equilibrium constants for the side chain reactions of para and meta substituted benzene derivatives. Hammett (37-39) noted that for a large number of reactions of these compounds plots of log k (or log K) for one reaction versus log k (or log K) for a second reaction of the corresponding member of a series of such derivatives was reasonably linear. Figure 7.5 is a plot of this type involving the ionization constants for phenylacetic acid derivatives and for benzoic acid derivatives. The point labeled p-Cl has for its ordinate log Ka for p-chlorophenylacetic acid and for its abscissa log Ka for p-chloroben-zoic acid. The points approximate a straight line, which can be expressed as... 

Chloro-2-nitropropane, 37, 25 5-Chloro-2-pentanone, 31, 74 a-CHLOROPHENYLACETIC ACID, 36, 3... 

In an in vitro fermentation study, rumen microorganisms metabolized both isomers of [ C]DDT o,p- and p,p-) to the corresponding DDD isomers at a rate of 12%/h. With p,//-DDT, 11% of the C detected was an unidentified polar product associated with microbial and substrate residues (Fries et al., 1969). In another in vitro study, extracts of Hydrogenomonas sp. cultures degraded DDT to DDD, l-chloro-2,2-bis(/5-chlorophenyl)ethane (DDMS), DBF, and several other products under anaerobic conditions. Under aerobic conditions containing whole cells, one of the rings is cleaved and p-chlorophenylacetic acid is formed (Pfaender and Alexander, 1972). 

Soil. p,//-DDD and p./Z-DDE are the major metabolites of /5,//-DDT in the environment (Metcalf 1973). In soils under anaerobic conditions, /5,//-DDT is rapidly converted to p,//-DDD via reductive dechlorination (Johnsen, 1976) and very slowly to p,//-DDE under aerobic conditions (Guenzi and Beard, 1967 Kearney and Kaufman, 1976). The aerobic degradation of p,pD yY under flooded conditions is very slow with p,//-DDE forming as the major metabolite. Dicofol was also detected in minor amounts (Lichtenstein et al., 1971). In addition to p./Z-DDD and /5,//-DDE, 2,2-bis(/5-chlorophenyl)acetic acid (DDA), bis(jo-chlorophenyl)methane (DDM), /5,/y dichlorobenzhydrol (DBH), DBF, and p-chlorophenylacetic acid (PCPA) were also reported as metabolites of /5,//-DDT in soil under aerobic conditions (Subba-Rao and Alexander, 1980). 

Biological. Reported degradation products by the microorganism Alcaligenes BM-2 for a mixture of polychlorinated biphenyls include monohydroxychlorobiphenyl, 2-hydroxy-6-oxochlorophenylhexa-2,4-dieonic acid, chlorobenzoic acid, chlorobenzoylpropionic acid, chlorophenylacetic acid, and 3-chlorophenyl-2-chloropropenic acid (Yagi and Sudo, 1980). When PCB-1016 was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum, no significant biodegradation was observed. At a concentration of 5 mg/L, percent losses after 7, 14, 21, and 28-d incubation periods were 44, 47, 46, and 48, respectively. At a concentration of 10 mg/L, only 22, 46, 20, and 13% losses were observed after the 7, 14, 21, and 28-d incubation periods, respectively (Tabak et al., 1981). 

Biological. Reported degradation products by the microorganism Alcaligenes BM-2 for a mixture of polychlorinated biphenyls include monohydroxychlorobiphenyl, 2-hydroxy-6-oxochlorophenyl-hexa-2,4-dieonic acid, chlorobenzoic acid, chlorobenzoylpropionic acid, chlorophenylacetic acid, and 3-chlorophenyl-2-chloropropenic acid (Yagi and Sudo, 1980). 

Salicylamide with 2-chlorophenylacetic acid followed by acetyl chloride gives the 3,5-dione (369). Similarly phenacyl bromide gives (370). 

The photostimulated carbonylation of aryl and vinyl halides by Co(CO)4" ions under phase-transfer catalysis conditions [Co2(CO)8, C6H6/NaOHaq, CO, Bu4N+Br", 65 °C] has been reported211,212. Thus PhBr, o- and /7-bromo toluenes, /7-bromoanisole, p-bromofluorobenzene, 4-bromoacetophenone and 1- and 2-bromonaphthalenes gave ArC02Na in 90-98% yields. Under the conditions used, carbonylation did not occur with unsubstituted PhCl, but when it was substituted, as in / -chlorobenzoic acid, or p-chlorophenylacetic acid, carbonylation was quantitative (98% yield). 

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