反応 #631978

反応方程式

NaNO2

3-Amino-2-methylbenzoic acid

HBr

HBr

→

3-bromo-2-methylbenzoic acid

溶媒

H2O

反応条件

後処理

1. 1
   workup.ADDITIONAfter the addition
2. 2
   ろ過filtered
3. 3
   ろ過The recovered filter cake
4. 4
   洗浄was washed first with water
5. 5
   乾燥with 10% HCl, and dried in air

実験手順

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).

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