反应 #540747

反应方程式

5-methylthiophene-2-carbaldehyde

bromine

sodium hydrogen carbonate

→

4-bromo-5-methylthiophene-2-carbaldehyde

收率 50.0%

溶剂

acetic acid

acetic acid

反应条件

后处理

1. 1
   workup.ADDITIONAfter the dropwise addition
2. 2
   萃取extracted with ethyl acetate
3. 3
   洗涤The ethyl acetate layer was washed with saturated brine
4. 4
   干燥dried (MgSO4)
5. 5
   浓缩concentrated
6. 6
   workup.DISSOLUTIONThe obtained residue was dissolved in toluene (50 mL)
7. 7
   workup.STIRRINGthe mixture was stirred at 110° C. for 2 hr
8. 8
   浓缩concentrated
9. 9
   洗涤eluted with ethyl acetate-hexane (1:5, volume ratio)
10. 10
    浓缩concentrated

实验过程

To a solution of 5-methylthiophene-2-carbaldehyde (50.0 g) in acetic acid (400 mL) was added dropwise a solution of bromine (25 mL) in acetic acid (200 mL) at room temperature over 6 hr. After the dropwise addition, the reaction mixture was stirred overnight, neutralized with saturated aqueous sodium hydrogen carbonate solution, and extracted with ethyl acetate. The ethyl acetate layer was washed with saturated brine, dried (MgSO4) and concentrated. The obtained residue was dissolved in toluene (50 mL), and the mixture was stirred at 110° C. for 2 hr and concentrated. The residue was subjected to silica gel column chromatography, eluted with ethyl acetate-hexane (1:5, volume ratio) and concentrated to give 4-bromo-5-methylthiophene-2-carbaldehyde (40.0 g, yield 50%) as yellow crystals. melting point 60° C.

来源