Thioglycolic Acid → 2,5-Dichlorobenzenethiol

Participants

Reaction Conditions

Reaction Steps

To a 300 ml four-necked flask equipped with a stirrer, a thermometer and a condenser were charged 24.9 g (0.110 mol) of 1-bromo-2,5-dichlorobenzene, 13.19 g (0.143 mol) of thioglycolic acid, 12.06 g (0.286 mol) of 95% sodium hydroxide and 100 g of dimethylsulfoxide, followed by stirring at 120° C. for 4 hours. After cooling until 100° C., 2,5-dichlorothiophenol salt produced as the side product was treated with 5.13 g (0.044 mol) of sodium monochloroacetate at the same temperature for 1 hour. Then, after distilling off the dimethylsulfoxide under reduced pressure, 100 g of water was added to 54.5 g of the residue. After dissolving the residue therein at 100° C., the solution was cooled for crystallization and filtered to yield sodium 2,5-dichlorophenylthioglycolate, which was then dissolved in 100 g of water with heating and acidized with concentrated hydrochloric acid, filtered and dried to yield 23.5 g of a light yellowish white powder of 2,5-dichlorophenylthioglycolic acid. The yield based on 1-bromo-2,5-dichlorobenzene was 90.0%.

Provenance & Evidence