反応 #2441549

反応方程式

trifluoroacetic acid

7-(methyloxy)-2H-1,4-benzoxazin-3(4H)-one

sodium hydride

ethyl bromoacetate

→

ethyl [7-(methyloxy)-3-oxo-2,3-dihydro-4H-1,4-benzoxazin-4-yl]acetate

収率 64.6%

溶媒

CH3CN H2O

THF

THF

反応条件

後処理

1. 1
   workup.STIRRINGstirred at room temperature for two hours
2. 2
   その他had formed
3. 3
   その他The reaction was quenched with 5 mL of 4.0M HCl in dioxane
4. 4
   その他The solvent was removed by rotary evaporation
5. 5
   その他purified by column chromatography (120 g silica gel 40 um, gradient elution from 100% dichloromethane to 10% methanol/90% dichloromethane over 40 minutes)

実験手順

A solution of 7-(methyloxy)-2H-1,4-benzoxazin-3(4H)-one (1.42 g, 7.9 mmol) dissolved in 5 mL of anhydrous THF was added to a suspension of sodium hydride (0.349 g of a 60% dispersion in mineral oil, 8.7 mmol) in 10 mL of anhydrous THF at room temperature and stirred for 10 minutes. Then, ethyl bromoacetate (1.06 mL, 9.52 mmol) was added and stirred at room temperature for two hours. HPLC (Eclipse XDB-C18, 4.6×250 mm, 5 micron, 1-99% CH3CN/H2O with 0.1% trifluoroacetic acid) showed that all of the starting material (Rt=4.4 min) was gone and that a new peak (Rt=6.5 min) had formed. The reaction was quenched with 5 mL of 4.0M HCl in dioxane. The solvent was removed by rotary evaporation and the residue was adsorbed onto approximately 10 g of silica gel and purified by column chromatography (120 g silica gel 40 um, gradient elution from 100% dichloromethane to 10% methanol/90% dichloromethane over 40 minutes) to give ethyl [7-(methyloxy)-3-oxo-2,3-dihydro-4H-1,4-benzoxazin-4-yl]acetate (1.35 g, 5.1 mmol, 64%) as a white crystalline solid. MS (ES) m/e 266 [M+H]+.

出典