反応 #1880957

反応方程式

methyl 4-allyl-2-(ethoxycarbonylmethoxy)phenoxyacetate

sodium hydride

hydrochloric acid

→

7-allylbenzo[b][1,4]dioxepin-3-one

収率 42.0%

溶媒

tetrahydrofuran

反応条件

後処理

1. 1
   温度The reaction mixture was then refluxed for 20 h
2. 2
   温度after cooling
3. 3
   抽出extracted three times
4. 4
   乾燥The combined ether extracts were dried over sodium sulfate
5. 5
   その他freed from solvent on a rotary evaporator
6. 6
   workup.ADDITION400 ml of 2N hydrochloric acid were added
7. 7
   温度the mixture was refluxed for 20 h
8. 8
   workup.ADDITIONThe mixture was then poured into 1.5 l of ice water
9. 9
   抽出the product was extracted four times
10. 10
    洗浄each time with 1.5 l of ether, and the combined ether extracts were washed with 1 l of water and 100 ml of saturated sodium chloride solution
11. 11
    乾燥After drying over sodium sulfate, concentration on a rotary evaporator and flash chromatography

実験手順

A solution of 69.0 g (234 mmol) of methyl 4-allyl-2-(ethoxycarbonylmethoxy)phenoxyacetate was added dropwise in the course of 2.5 h to a suspension of 12.0 g (500 mmol) of sodium hydride in 500 ml of tetrahydrofuran. The reaction mixture was then refluxed for 20 h and, after cooling, poured into 1.5 l of ice water. The resultant mixture was acidified to pH 2 with 2N hydrochloric acid and extracted three times, each time with 2 l of ether. The combined ether extracts were dried over sodium sulfate, freed from solvent on a rotary evaporator and taken up into 400 ml of ethanol. 400 ml of 2N hydrochloric acid were added and the mixture was refluxed for 20 h. The mixture was then poured into 1.5 l of ice water, the product was extracted four times, each time with 1.5 l of ether, and the combined ether extracts were washed with 1 l of water and 100 ml of saturated sodium chloride solution. After drying over sodium sulfate, concentration on a rotary evaporator and flash chromatography. (pentane/ether, 4:1, Rf=0.37) on silica gel, 20.0 g (42%) of 7-allylbenzo[b][1,4]dioxepin-3-one (1) were obtained as a colorless liquid.

出典