Reaktion #2122482

Reaktionsgleichung

3-(2,5-dimethyl-phenyl)-4-hydroxy-8-methoxy-1-oxa-8-aza-spiro[4.5]dec-3-en-2-one

triethylamine

4-dimethylaminopyridine DMAP

ethyl chloroformate

→

crude product

carbonic acid 3-(2,5-dimethyl-phenyl)-8-methoxy-2-oxo-1-oxa-8-aza-spiro[4.5]dec-3-en-4-yl ester ethyl ester

Lösungsmittel

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITleft
2. 2
   SonstigeThen the solvent was removed under vacuum
3. 3
   workup.ADDITIONEthyl acetate was added to the residue
4. 4
   Sonstigethe precipitation
5. 5
   Filtrationwas filtered off
6. 6
   EinengenThe filtrate was concentrated under vacuum

Vorschrift

To a solution of 3-(2,5-dimethyl-phenyl)-4-hydroxy-8-methoxy-1-oxa-8-aza-spiro[4.5]dec-3-en-2-one (120 mg, 0.40 mmol), triethylamine (0.08 ml, 60 mg, 0.60 mmol) and 4-dimethylaminopyridine DMAP (2 mg, 0.02 mmol) in 4 ml THF at 0° C. was added a solution of ethyl chloroformate (0.05 ml, 52 mg, 0.50 mmol) dissolved in 1 ml THF dropwise. The suspension was kept at 0° C. for 30 minutes under argon and left stirring at room temperature overnight. Then the solvent was removed under vacuum. Ethyl acetate was added to the residue and the precipitation was filtered off. The filtrate was concentrated under vacuum to give the crude product, which was purified by column chromatography on silica gel (ethyl acetate/cyclohexane 1:9). Yield: 111 mg of carbonic acid 3-(2,5-dimethylphenyl)-8-methoxy-2-oxo-1-oxa-8-aza-spiro[4.5]dec-3-en-4-yl ester ethyl ester (title compound P1.1) as a light yellow gum.

Quelle