Reaction #640603

Reaction equation

water

5-acetyl-7a-pyrrolidin-1-yl-3a,4,5,6,7,7a-hexahydro-isoxazolo[4,5-c]pyridine-3-carboxylic acid ethyl ester

trifluoroacetic acid

→

5-acetyl-4,5,6,7-tetrahydro-isoxazolo[4,5-c]pyridine-3-carboxylic acid ethyl ester

Solvents

DCM

Conditions

Workup

1. 1
   Temperaturewas heated
2. 2
   Temperatureto reflux for 8 h
3. 3
   Dryingthe organic phase was dried over MgSO4
4. 4
   Otherthe solvent removed under a vacuum
5. 5
   OtherThe remaining brown oil was purified by column chromatography (SiO2, EtOAc/EtOH 10:1)

Procedure

A mixture of 18.0 g (58 mmol) of 5-acetyl-7a-pyrrolidin-1-yl-3a,4,5,6,7,7a-hexahydro-isoxazolo[4,5-c]pyridine-3-carboxylic acid ethyl ester (B) in 150 mL of DCM and 6.47 mL (87 mmol) of trifluoroacetic acid was heated to reflux for 8 h. After addition of 100 mL of water, the organic phase was dried over MgSO4 and the solvent removed under a vacuum. The remaining brown oil was purified by column chromatography (SiO2, EtOAc/EtOH 10:1). 12.5 g (90% of theoretical) of the desired product 5-acetyl-4,5,6,7-tetrahydro-isoxazolo[4,5-c]pyridine-3-carboxylic acid ethyl ester (C) were obtained in the form of a brown-yellow oil.

Source