Acetic Acid → 3-Fluoro-4-hydroxybenzoic acid

Participants

Reaction Steps

98.8 g of 3-fluoro-4-methoxy benzoic acid was mixed with 215 ml of concentrated hydrogen bromide solution and 215 ml of acetic acid and heated under reflux for 34 hours with stirring. Thereafter, the reaction mixture was cooled with water, and the precipitated crystal was filtered to obtain a blackish brown crystal. This crystal was recrystallized with water to obtain 77.73 g (yield: 86%) of a black crystal. Moreover, the use of this crystal itself caused no problem at the subsequent step though it may be changed into white by further purification.

Provenance & Evidence