Boron Trichloride → 5-Amino-2-bromophenol

Temperature

-78 °C

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]+).

1. customThe cooling bath was removed
2. additionthe reaction mixture was poured onto ice water (4.5 kg)
3. extractionThe organic layer was extracted with water
4. washThe combined aqueous layers were washed with dichloromethane
5. additionSodium chloride was added until saturation
6. extractionThe aqueous layer was extracted with ethyl acetate
7. dry with materialThe combined organic layers were dried over sodium sulfate
8. filtrationfiltered
9. customthe solvents were evaporated
10. washThe solid was washed with dichloromethane
11. customdried under vacuum

ORD record

ord-1dd26acb462b4d6198229feccd8cef38

Source dataset

uspto-grants-2004_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06787558B2