Thioglycolic Acid → 2-(2,5-Dichlorophenyl)-2-mercaptoacetic acid

Beteiligte Stoffe

Reaktionsschritte

To a 500 ml flask equipped with a thermometer, a condenser and a stirrer were added 45.2 g (0.2 mol) of 1-bromo-2,5-dichlorobenzene, 23.7 g (0.4 mol) of 95% potassium hydroxide, 18.4 g (0.2 mol) of thioglycolic acid and 320 g of N-methyl-2-pyrrolidone, followed by stirring at 140° to 150° C. for 2 hours. Assay of the reaction solution by high performance liquid chromatography identified the solution as a mixture of dichlorophenylthioglycolate and dichlorothiophenol salt. Then, after distilling off the solvent, 300 g of water and 50 g of toluene were added for layer separation. To the water layer was added 45 g of concentrated hydrochloric acid, and the mixture was cooled to room temperature. The resulting crystal was filtered and dried to yield 28.7 g of 2,5-dichlorophenylthioglycolic acid. Its melting point was 129° to 131° C., and the yield was 60.5%. The results are given in Table 2.

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