Boron Trichloride → 5-Amino-2-bromophenol

Participants

Reaction Conditions

Reaction Steps

A suspension of 4-bromo-3-methoxy-phenylamine (37.6 g, 0.186 mol) and tetrabutylammonium iodide (96 g, 0.260 mol) in dichloromethane (1.2 L) was cooled down to −78° C. A 1M solution of boron trichloride in dichloromethane (520 mL, 0.521 mol) was added dropwise, within 20 min. The cooling bath was removed. After 3 hours, the reaction mixture was poured onto ice water (4.5 kg). The organic layer was extracted with water. The combined aqueous layers were washed with dichloromethane. The pH was adjusted to 9 using sodium hydrogencarbonate. Sodium chloride was added until saturation. The aqueous layer was extracted with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered and the solvents were evaporated. The solid was washed with dichloromethane and dried under vacuum. 35.2 g of the title compound were obtained. Brown solid, ISP-MS: m/e=189.1 ([M+H]+).

Provenance & Evidence