Phenol → 2-Fluorobenzoyl chloride

Participants

Reaction Steps

To a stirred suspension of 95.4 g of 2-fluorobenzoic acid, 2-(4-(trifluoromethyl)phenylhydrazide, in 400 ml of anhydrous diethyl ether was added, portionwise, 80.0 g of phosphorous pentachloride. Upon completion of the addition, the reaction mixture was refluxed for 1 hour and then stirred at room temperature for 16 hours. In the following order, a solution of 81.3 g of phenol in 80 ml of diethyl ether, 385 ml of methanol and sufficient water to reach the solution cloud point, were added, dropwise, to the reaction mixture. Upon standing, the reaction mixture separated into two layers. The top layer (aqueous) was extracted with diethyl ether and the extract added to the bottom layer (organic). The combined organic phase was washed with water, dried over anhydrous magnesium sulfate and concentrated to an oil. The oil was purified on a Water's Model 500 High Pressure Liquid Chromatograph using two silica gel columns and 5% ethyl acetate-hexane as the eluent. Concentration of the appropriate fractions gave 79.6 g (78.5%) of α-chloro-2-fluorobenzaldehyde, [4-(trifluoromethyl)phenyl]-hydrazone. Subsequent recrystallization from hexane gave an analytical sample, mp 48°-50°.

Provenance & Evidence