Ethylparaben → Ethyl 3-bromo-4-hydroxybenzoate

Participants

Reaction Conditions

Reaction Steps

This procedure is modified from the work of Oberhauser (J. Org. Chem, 1997, 62,4504). To a solution of 4-hydroxybenzoic acid ethyl ester (57.8 g, 348 mmol) in 480 mL of dry acetonitrile was added HBF4 Et2O (54% in Et2O, 32.9 mL). The solution was cooled to −15° C. with an ice/methanol bath. N-bromosuccinimide (67.2 g, 378 mmol) was added portionwise at a rate where the temperature would not rise above −10° C. After addition was complete, the cooling bath was removed and the reaction mixture was allowed to stir overnight at room temperature. Worked up by pouring the reaction mixture into aqueous sodium bisulfite (38%, 200 mL) and extracting four times with ethyl acetate. The organic layers were combined, washed with water, saturated brine, dried over anhydrous sodium sulfate, decanted, and concentrated in vacuo to give a white solid. Recrystallization from ethyl acetate/hexane gave 3-bromo-4-hydroxybenzoic acid ethyl ester (70.7 g, 83%) as a white solid. 1H NMR (300 MHz, CDCl3) δ 1.39 (t, J=6.7 Hz, 3H, —CO2CH2CH3), 4.34 (t, J=6.7 Hz, 2H, —CO2CH2CH3), 7.02 (d, 1H, arom), 7.91 (dd, 1H, arom), 8.19 (d, 1H, arom).

Provenance & Evidence