反应 #66099

反应方程式

HBr

Thionyl chloride

tetrahydro-pyran-4-carboxylic acid

Trimethylsilyl diazomethane

→

2-bromo-1-(tetrahydro-pyran-4-yl)-ethanone

收率 35.0%

溶剂

acetic acid

反应条件

后处理

1. 1
   其他Excess thionyl chloride was evaporated
2. 2
   其他the residue co-distilled with toluene to remove the traces of thionyl chloride
3. 3
   workup.DISSOLUTIONThe resulting crude acid chloride was dissolved in dry acetonitrile (3 mL)
4. 4
   温度cooled to 0° C
5. 5
   workup.STIRRINGthe reaction mixture was stirred at ambient temperature for 2 h
6. 6
   温度It was then cooled to −10° C.
7. 7
   workup.STIRRINGThe mixture was stirred at room temperature for 1 h
8. 8
   其他then quenched with saturated sodium bicarbonate solution
9. 9
   萃取extracted with ether (3×20 mL)
10. 10
    洗涤The combined ether extracts were washed with brine
11. 11
    干燥dried over anhydrous sodium sulfate
12. 12
    浓缩concentrated in vacuo

实验过程

Thionyl chloride (2 mL, 27 mmol) was added to tetrahydro-pyran-4-carboxylic acid (1.1 g, 8.4 mmol) at 10° C. The mixture was warmed to ambient temperature and stirred for 2 h. Excess thionyl chloride was evaporated and the residue co-distilled with toluene to remove the traces of thionyl chloride. The resulting crude acid chloride was dissolved in dry acetonitrile (3 mL) and cooled to 0° C. Trimethylsilyl diazomethane (12.6 mL, 25.3 mmol) was added and the reaction mixture was stirred at ambient temperature for 2 h. It was then cooled to −10° C. and a solution of 15% HBr in acetic acid (2 mL) was added. The mixture was stirred at room temperature for 1 h then quenched with saturated sodium bicarbonate solution and extracted with ether (3×20 mL). The combined ether extracts were washed with brine, dried over anhydrous sodium sulfate and concentrated in vacuo to afford 2-bromo-1-(tetrahydro-pyran-4-yl)-ethanone (620 mg, 35%) as an oil.

来源