Reacción #2122482

Ecuación de reacción

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

Disolventes

THF

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.WAITleft
2. 2
   OtroThen the solvent was removed under vacuum
3. 3
   workup.ADDITIONEthyl acetate was added to the residue
4. 4
   Otrothe precipitation
5. 5
   Filtraciónwas filtered off
6. 6
   ConcentraciónThe filtrate was concentrated under vacuum

Procedimiento

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.

Fuente