反応 #2122486

反応方程式

water

4-hydroxy-8-methoxy-3-(2,4,6-trimethyl-phenyl)-1-oxa-8-aza-spiro[4.5]dec-3-en-2-one

triethylamine

ethyl chloroformate

→

carbonic acid ethyl ester 8-methoxy-2-oxo-3-(2,4,6-trimethylphenyl)-1-oxa-8-aza-spiro[4.5]dec-3-en-4-yl ester

溶媒

THF

THF

反応条件

後処理

1. 1
   抽出extracted three times with ethyl acetate
2. 2
   乾燥The combined organic layers were dried over sodium sulfate
3. 3
   濃縮concentrated
4. 4
   その他The crude product (brown oil) was purified by column chromatography on silica gel (ethyl acetate/cyclohexane 1:1)

実験手順

To a solution of crude (ca 50% purity) 4-hydroxy-8-methoxy-3-(2,4,6-trimethyl-phenyl)-1-oxa-8-aza-spiro[4.5]dec-3-en-2-one (1.0 g, 3.15 mmol), triethylamine (0.8 ml, 0.57 g, 5.67 mmol) in 6 ml THF at 0° C. under argon was added ethyl chloroformate (0.36 ml, 0.41 g, 3.78 mmol) dropwise. The suspension became immediately quite thick. It was diluted with additional 2 ml THF while stirring was continued at 0° C. for 30 minutes. The reaction mixture was poured into cold water (0° C.) and extracted three times with ethyl acetate. The combined organic layers were dried over sodium sulfate and concentrated. The crude product (brown oil) was purified by column chromatography on silica gel (ethyl acetate/cyclohexane 1:1). Yield: 220 mg of carbonic acid ethyl ester 8-methoxy-2-oxo-3-(2,4,6-trimethyl-phenyl)-1-oxa-8-aza-spiro[4.5]dec-3-en-4-yl ester (title compound P1.5) as a white solid.

出典