m-Chloroperbenzoic acid → 5-Bromo-2-methoxyphenol

Participants

Reaction Steps

A solution of 5-bromo-2-ethoxy-benzaldehyde (50 g, 233 mmol), in CH2Cl2 (150 mL) at 0-5° C., was treated with a solution of 3-chloroperoxybenzoic acid (70-75% purity) (68.1 g, 276 mmol) in CH2Cl2 (500 mL) and the reaction mixture allowed to warm slowly to room temperature and stirred for 72 h. The resulting precipitate was filtered and the filtrate then stirred for 2 h with a 2 N aqueous Na2SO2O3 solution (200 mL). The organic layer was then concentrated, dissolved in diethyl ether, and washed with an aqueous 1 N Na2SO3 followed by a half saturated NaHCO3 solution. The organic phase was extracted with a 2 N aqueous NaOH solution and the combined basic extract acidified (pH ˜3-4) with concentrated HCl. The acidified mixture was extracted with diethyl ether, dried over MgSO4, filtered, and evaporated to afford intermediate 5-bromo-2-methoxy-phenol (43.5 g, 90%). 1H NMR (CDCl3) 7.06 (br s, 1H), 6.96 (dd, J=8.6, 2.3, 1H), 6.70 (d, J=8.6, 1H), 5.67 (s, 1H), 4.05 (q, J=7.1, 2H), 1.44 (t, J=7.1, 3H).

Provenance & Evidence