Reaktion #87123

Reaktionsgleichung

N,O-dimethylhydroxylamine HCl

(S)-2-(tert-Butoxycarbonylamino)-3-cyclopentenylpropanoic acid

ethyl chloroformate

NMM

→

(S)-tert-butyl (3-(cyclopent-1-en-1-yl)-1-(methoxy(methyl)amino)-1-oxopropan-2-yl)carbamate

Ausbeute 94.0%

Lösungsmittel

DCM

THF DCM

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONAfter addition
2. 2
   TemperaturThe mixture was cooled to 0° C.
3. 3
   Temperaturto warm to ambient temperature
4. 4
   workup.STIRRINGstirred overnight
5. 5
   SonstigeThe mixture was quenched with water (500 mL)
6. 6
   Waschenthe organic phase was washed with water (500 mL)
7. 7
   Trocknendried over anhydrous sodium sulfate
8. 8
   Einengenconcentrated

Vorschrift

To a flask charged with (S)-2-(tert-Butoxycarbonylamino)-3-cyclopentenylpropanoic acid (55.0 g, 214 mmol) was added THF/DCM (800 mL, 1:1). The solution was cooled to 0° C. and ethyl chloroformate (24.5 mL, 257 mmol) and NMM (28.4 mL, 257 mmol) were added dropwise sequentially. After addition, the mixture was stirred at 0° C. under nitrogen for 1 h. To the other flask charged with N,O-dimethylhydroxylamine HCl (25 g, 257 mmol) was added DCM (400 mL). The mixture was cooled to 0° C. and TEA (38.7 mL, 278 mmol) was added. The resulting mixture was transferred into the former reaction flask. The reaction mixture was allowed to warm to ambient temperature and stirred overnight. The mixture was quenched with water (500 mL) and the organic phase was washed with water (500 mL), dried over anhydrous sodium sulfate, and concentrated to afford (S)-tert-butyl (3-(cyclopent-1-en-1-yl)-1-(methoxy(methyl)amino)-1-oxopropan-2-yl)carbamate as colorless oil (60 g, 93% yield), which was used in the next step without further purification.

Quelle