Hydrogen Bromide → 3-Bromo-2-methylbenzoic Acid
Reaction equation
N[C:2]1[C:3]([CH3:11])=[C:4]([CH:8]=[CH:9][CH:10]=1)[C:5]([OH:7])=[O:6].N([O-])=O.[Na+].[BrH:16]>O>[Br:16][C:2]1[C:3]([CH3:11])=[C:4]([CH:8]=[CH:9][CH:10]=1)[C:5]([OH:7])=[O:6]Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 0 °C
Procedure
3-Amino-2-methylbenzoic acid (6.16 g) was heated at reflux for 30 minutes in concentrated HBr. The mixture was cooled to 0° C. and treated with a solution of NaNO2 at 0° C. (2.8 g in 5.6 mL H2O). The resultant diazonium salt solution was slowly added to a preheated (60-70° C.) solution of CuBr (3.8 g) in 3.2 mL concentrated HBr. After the addition, the mixture was stirred overnight at room temperature and filtered. The recovered filter cake was washed first with water and then with 10% HCl, and dried in air to yield 6.93 g of 3-bromo-2-methylbenzoic acid as a light purple powdery solid. This material was dissolved in ethyl acetate, washed twice with 5% HCl, dried over Na2SO4, and recrystallized from 4:1 hexanes:ethyl acetate first at room temperature and then under refrigeration. 1H NMR (DMSO, 200 MHz), δ (ppm): 7.72 (dd, 2H), 7.2 (t, 1H), 2.5 (s, 3H).
Workup
- additionAfter the addition
- filtrationfiltered
- filtrationThe recovered filter cake
- washwas washed first with water
- dry with materialwith 10% HCl, and dried in air
Sources & evidence
- ORD record
- ord-4b226af17d7340cd91242b96f25c6669
- Source dataset
- uspto-grants-2015_10
- Patent number
- US09163256B2
Reaction notes
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