反应详情

温度

0 °C

57.1 To a stirred, cooled (0° C.) solution of the 1.6 g 3-aminopyrazole in DMF under an argon atmosphere was added potassium tert-butylate. After 30 min. stirring at 0° C., ethyl iodoacetate was added in one portion. After 2 h stirring at 0° C., the ice bath was removed and stirring at r.t. was continued for 22 h. The mixture was concentrated in order to remove as much DMF as possible. The residue was taken up in EtOAc and washed with H2O. The aqueous phase was extracted with EtOAc. The combined organics were washed with H2O and brine, dried (MgSO4), filtered and concentrated. The crude product was purified by chromatography on silica using a gradient from cyclohexane to EtOAc in 40 min to give 366 mg (3-amino-pyrazol-1-yl)-acetic acid ethyl ester as viscous yellow oil.

1. stirringAfter 2 h stirring at 0° C.
2. customthe ice bath was removed
3. stirringstirring at r.t.
4. waitwas continued for 22 h
5. concentrationThe mixture was concentrated in order
6. customto remove as much DMF as possible
7. washwashed with H2O
8. extractionThe aqueous phase was extracted with EtOAc
9. washThe combined organics were washed with H2O and brine
10. dry with materialdried (MgSO4)
11. filtrationfiltered
12. concentrationconcentrated
13. customThe crude product was purified by chromatography on silica using a gradient from cyclohexane to EtOAc in 40 min