反应 #631978

反应方程式

NaNO2

3-Amino-2-methylbenzoic acid

HBr

HBr

→

3-bromo-2-methylbenzoic acid

溶剂

H2O

反应条件

后处理

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

实验过程

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).

来源