3-(4-Methoxyphenoxy)benzoic acid → 3-(4-Hydroxyphenoxy)benzoic acid

Participants

Reaction Steps

An amount of 3-(4'-methoxyphenoxy)benzoic acid (40.7 g, 0.167 moles) was dissolved in 200 ml of acetic acid to which 150 ml of a 48 percent solution of hydrogen bromide (HBr) was added (Aldrich Chemical Company). The reaction mixture was heated to reflux under nitrogen for 14.5 hours. The cooled reaction mixture was then diluted with 400 ml of ethyl acetate (EtOAc), washed with saturated NaCl (3×150 ml), dried with MgSO4, filtered, and solvent evaporated to afford a dark brown solid. The crude product was dissolved in methanol, treated with activated carbon, filtered through a celite pad, and evaporated. Recrystallization of the product (1:1 acetic acid/water) gave 3-(4'-hydroxyphenoxy)benzoic acid as tan crystals with a m.p. of 163° C. to 166° C.

Provenance & Evidence