Dimethylformamide dimethyl acetal → Ethyl 1-(3-cyano-4-fluorophenyl)-5-(2-furyl)pyrazole-4-carboxylate

Temperatur

80 °C

To a solution of ethyl 3-(2-furyl)-3-ketopropionate (2.1 g, 11.5 mmol) in 20 mL of benzene was added dimethylformamide dimethylacetal (2.3 mL, 17.3 mmol). The resulting solution was stirred at 80° C. for 2 h. The reaction was cooled, filtered through a pad of silica gel and concentrated in vacuo. A portion of the residue (0.60 g, 2.54 mmol) was dissolved in 20 mL of glacial acetic acid and then there was added 4-fluoro-3-cyanophenylhydrazine tin chloride (1.05 g, 2.8 mmol). The reaction mixture was stirred at 100° C. for 4 h. The reaction was allowed to cool to room temperature and the acetic acid was removed in vacuo. The residue was diluted with ethyl acetate and the organics were washed with saturated aq NaHCO3 and brine, dried (MgSO4) and concentrated. The residue was purified by flash chromatography (elution with gradient of 6:1−>3:1 hexanes/ethyl acetate) to afford 0.32 g (39%) of the title compound. LRMS (ES+): 326.2 (M+H)+.

1. temperatureThe reaction was cooled
2. filtrationfiltered through a pad of silica gel
3. concentrationconcentrated in vacuo
4. stirringThe reaction mixture was stirred at 100° C. for 4 h
5. temperatureto cool to room temperature
6. customthe acetic acid was removed in vacuo
7. additionThe residue was diluted with ethyl acetate
8. washthe organics were washed with saturated aq NaHCO3 and brine
9. dry with materialdried (MgSO4)
10. concentrationconcentrated
11. customThe residue was purified by flash chromatography (elution with gradient of 6:1−>3:1 hexanes/ethyl acetate)

ORD-Eintrag

ord-02befd7a089a4bea8b42cfbb3868558d

Quelldatensatz

uspto-grants-2007_06

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07235575B2