Benzaldehyde → (S)-1-Benzyl-5-carboxy-2-pyrrolidinone

Temperature

0 °C

D-glutamic acid (1.47 g, 10 mmol) was dissolved in 2N aqueous sodium hydroxide (10 ml, 20 mmol) and stirred for 15 minutes. The mixture was then treated with a solution of benzaldehyde (1.1 ml, 10 mmol) in ethanol (3 ml) and stirred at room temperature for 30 minutes. The mixture was cooled to 0° C. and treated with sodium borohydride (0.030 g). The mixture was allowed to warm to room temperature with stirring over 4 hrs and then washed with diethyl ether (three times) before acidifying with concentrated hydrochloric acid to pH2. The resulting precipitate was filtered off and washed with diethyl ether before slurrying in ethanol and azeotroping three times with more ethanol. Finally the remaining material was slurried in ethanol (50 ml) and heated at reflux for 16 hrs. The mixture was then cooled to room temperature and evaporated in vacuo. Drying afforded pure 5-oxo-1-(phenylmethyl)proline.

1. stirringstirred at room temperature for 30 minutes
2. temperatureto warm to room temperature
3. stirringwith stirring over 4 hrs
4. washwashed with diethyl ether (three times)
5. filtrationThe resulting precipitate was filtered off
6. washwashed with diethyl ether
7. customazeotroping three times with more ethanol
8. temperatureheated
9. temperatureat reflux for 16 hrs
10. temperatureThe mixture was then cooled to room temperature
11. customevaporated in vacuo
12. customDrying

ORD record

ord-1898bb4dc3dc4c5ebc60dac149dd3dee

Source dataset

uspto-grants-2011_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08048907B2