Sulfuric Acid → 3-(3,5-Difluorophenoxy)propanoic acid

Participants

Reaction Steps

At about −20° C., 17.22 g (172.18 mmol) of chromium(VI) oxide were taken up in 1.2 l of acetone and 38 ml of water, and 19 ml of conc. sulfuric acid were slowly added to the mixture. The mixture was stirred for 10 min and then 8.10 g (43.05 mmol) of the compound from Example 168A in 400 ml of acetone were added dropwise over the course of 1 h. The mixture was stirred at 0° C. for 1.5 h. After addition of 90 ml of propan-2-ol, the reaction mixture was filtered through kieselguhr, the solvents were removed from the filtrate in vacuo, and the residue was taken up in 500 ml of diethyl ether. The solution was washed twice with saturated aqueous sodium chloride solution and dried over sodium sulfate, and the solvents were removed in vacuo. 11.36 g of the title compound were obtained and were reacted further in the next stage without further purification.

Provenance & Evidence