反応 #55201

反応方程式

potassium hydroxide

triphenylphosphoranylideneacetic acid ethyl ester

4-(1-bromoethyl)-2',4'-difluorobiphenyl

ethyl acetate

→

3-(2',4'-difluoro-4-biphenylyl)butyric acid

溶媒

methanol

反応条件

後処理

1. 1
   温度under reflux for 54 hours
2. 2
   ろ過The precipitate is filtered off
3. 3
   その他the filtrate is evaporated
4. 4
   その他Crude [1-(2',4'-difluoro-4-biphenylyl)ethyl]-triphenylphosphoranylideneacetic acid ethyl ester thus obtained
5. 5
   workup.DISSOLUTIONis dissolved in 500 ml
6. 6
   温度the mixture is heated
7. 7
   温度under reflux for one hour
8. 8
   workup.DISTILLATIONThe methanol is distilled off
9. 9
   workup.ADDITIONwater is added
10. 10
    洗浄the reaction mixture is washed with ether

実験手順

69.7 g. of triphenylphosphoranylideneacetic acid ethyl ester and 29.7 g. of 4-(1-bromoethyl)-2',4'-difluorobiphenyl in 300 ml. of absolute ethyl acetate are heated under reflux for 54 hours. The precipitate is filtered off and the filtrate is evaporated. Crude [1-(2',4'-difluoro-4-biphenylyl)ethyl]-triphenylphosphoranylideneacetic acid ethyl ester thus obtained is dissolved in 500 ml. of methanol to which 150 ml. of 20% potassium hydroxide solution are added and the mixture is heated under reflux for one hour. The methanol is distilled off, water is added and the reaction mixture is washed with ether and acidified with hydrochloric acid to give 3-(2',4'-difluoro-4-biphenylyl)butyric acid, m.p. 109°-110°.

出典