Reaction #1340612

Reaction equation

hydrochloric acid

sodium hydroxide

ethyl 4-[(3S,4S)-3-(tert-butoxycarbonyl)amino-4-methylpyrrolidin-1-yl]-2,5-difluoro-3-methylbenzoate

→

title compound

4-[(3S,4S)-3-(tert-Butoxycarbonyl)amino-4-methylpyrrolidin-1-yl]-2,5-difluoro-3-methylbenzoic acid

Solvents

ethanol

ethanol

Conditions

Workup

1. 1
   Otherwas removed under reduced pressure
2. 2
   workup.ADDITIONSubsequently, 1 mol/L hydrochloric acid was added to the residue
3. 3
   Extractionthe mixture was extracted with ethyl acetate (200 mL×2)
4. 4
   Dryingby drying over anhydrous sodium sulfate
5. 5
   FiltrationAfter filtration
6. 6
   Concentrationthe filtrate was concentrated under reduced pressure
7. 7
   Otherdried under reduced pressure (solvent)

Procedure

A 1 mol/L aqueous sodium hydroxide solution (15 mL, 15 mmol) was added under cooling with ice to a solution of ethyl 4-[(3S,4S)-3-(tert-butoxycarbonyl)amino-4-methylpyrrolidin-1-yl]-2,5-difluoro-3-methylbenzoate (2.51 g, 6.30 mmol) in ethanol (20 mL), followed by stirring at room temperature for 20 hours. The resultant mixture was neutralized with 1 mol/L hydrochloric acid under cooling with ice, and ethanol was removed under reduced pressure. Subsequently, 1 mol/L hydrochloric acid was added to the residue, and the mixture was extracted with ethyl acetate (200 mL×2), followed by drying over anhydrous sodium sulfate. After filtration, the filtrate was concentrated under reduced pressure, and dried under reduced pressure (solvent), to thereby yield the title compound as a yellow oily substance (2.20 g, quantitative amount). The product was employed, without further purification, in the subsequent step.

Source