Pyridine → 2-[2-(4-Fluorophenyl)acetyl]-4-(4-nitro-phenoxycarbonyloxy)-pyrazolidine-1-carboxylic acid benzyl ester

温度

0 °C

2-[2-(4-Fluorophenyl)acetyl]-4-hydroxy-pyrazolidine-1-carboxylic acid benzyl ester, 38, (366 mg, 1.02 mmol) is dissolved in dichloromethane (10 mL). The solution is cooled to 0° C. and p-nitrophenyl chloroformate (411 mg, 2.04 mmol) is added in one portion. The solution is stirred at 0° C., and pyridine (198 μL, 2.45 mmol) added. Stirring is continued at 0° C. for 1 hour followed by stirring at room temperature for 12 hours. The reaction is diluted with water (40 mL) and extracted with dichloromethane (40 mL). The organic layer is washed with 0.5 N NaOH (2×40 mL). The combined aqueous layers are back-extracted extracted with dichloromethane (30 mL). The combined organic layers are washed with brine (30 mL), dried, filtered, and concentrated in vacuo. The crude material is purified over silica (3:1 to 2:1 to 1:1 hexane/ethyl acetate) to afford 462 mg (86% yield) of the desired product as a white foam.

1. stirringStirring
2. stirringby stirring at room temperature for 12 hours
3. extractionextracted with dichloromethane (40 mL)
4. washThe organic layer is washed with 0.5 N NaOH (2×40 mL)
5. extractionThe combined aqueous layers are back-extracted
6. extractionextracted with dichloromethane (30 mL)
7. washThe combined organic layers are washed with brine (30 mL)
8. customdried
9. filtrationfiltered
10. concentrationconcentrated in vacuo
11. customThe crude material is purified over silica (3:1 to 2:1 to 1:1 hexane/ethyl acetate)

ORDレコード

ord-07899571ac004176a04f3732b5db25f0

出典データセット

uspto-grants-2006_08

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US07087615B2