Hydrogen Bromide → 4-Bromo-3-methylbenzoic acid

Temperature

25 °C

A suspension of compound of Example 1a (73 g, 0.483 mol) in water (411 mL) and 47% HBr (486 mL) was stirred at 25° C. for 1 h and then the reaction mixture was cooled to −2° C. A solution of sodium nitrate (32 g, 0.463 mol) in water (100 mL) was added to the reaction mixture over a period of 15 min, maintaining the temperature at −1° C. to −2° C. The reaction mixture was stirred at −1° C. to −2° C. for 1.5 h. The reaction mixture was added slowly to a suspension of copper(I)bromide (73 g, 0.508 mol) in water (73 mL) and aqueous HBr (73 mL). The reaction mixture was stirred at 25° C. for 1 h and then digested at 70° C. for 1 h. The solid was filtered, washed with water till the pH of the filtrate was 7 and dried to obtain the title compound. Yield: 94 g (90%); 1H NMR (DMSO-d6, 300 MHz): δ 2.37 (s, 3H, CH3), 7.64 (m, 2H, Ar), 7.87 (s, 1H, Ar); MS: m/e (ES−) 214 (M−1).

1. temperaturethe reaction mixture was cooled to −2° C
2. temperaturemaintaining the temperature at −1° C. to −2° C
3. stirringThe reaction mixture was stirred at −1° C. to −2° C. for 1.5 h
4. stirringThe reaction mixture was stirred at 25° C. for 1 h
5. waitdigested at 70° C. for 1 h
6. filtrationThe solid was filtered
7. washwashed with water till the pH of the filtrate
8. customdried

ORD record

ord-e9a31fbb68fc4be297edb13b2a50006d

Source dataset

uspto-grants-2010_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07834052B2