Hydrochloric Acid → 2-Fluoro-4-(methoxycarbonyl)benzoic acid

Participants

Reaction Steps

A solution of 80% NaClO2 (0.13 mol) in H2O (50 mL) is added dropwise to a solution of crude 3-fluoro-4-formyl benzoic acid methyl ester (4, 0.12 mol) and sulfamic acid (0.13 mol) in H2O (50 mL) and CH3CN (100 mL). After stirring for 1 h, the reaction mixture is poured into saturated Na2SO3 aqueous solution and 1 N HCl, and extracted three times with EtOAc. The combined organic layers are washed with brine, dried over MgSO4, and evaporated in vacuo. The crystals are collected by filtration and washed with ether/hexane (1:1) to give 2-fluoroterephthalic acid 4-methyl ester (5) as white solid.

Provenance & Evidence