Hydrazine hydrate (1:1) → HCID 178498888, compound

Temperature

-50 °C

At −50° C., a solution of methyl 4,4-difluoro-3-oxo-2-(1-piperidin-1-ylmethylidene)butyrate (97.9%, 20.0 g, 79 mmol) in toluene (150 ml) was added dropwise to a solution of hydrazine hydrate (100%, 4.36 g, 87 mmol) in toluene (150 ml). The reaction mixture was stirred at −50° C. for 2 h and then, over a period of 1 hour, warmed to room temperature. The reaction mixture was washed with deionized water (100 ml). After separation of the phases, the aqueous phase was extracted once with toluene (100 ml). The toluene phases were combined and washed with an aqueous saturated NaCl solution (100 ml), and the solvent was then removed under reduced pressure. According to GC analysis, the residue obtained (9.2 g) consisted to 65.3% of methyl 3-difluoromethyl-1H-pyrazol-4-yl-carboxylate (Yield: 66%). 1H-NMR (CDCl3): δ=3.9 (s, 3H), 7.25 (t, 1H), 8.2 ppm (s, 1H).

1. waitover a period of 1 hour
2. temperaturewarmed to room temperature
3. washThe reaction mixture was washed with deionized water (100 ml)
4. customAfter separation of the phases
5. extractionthe aqueous phase was extracted once with toluene (100 ml)
6. washwashed with an aqueous saturated NaCl solution (100 ml)
7. customthe solvent was then removed under reduced pressure
8. customthe residue obtained (9.2 g)

ORD record

ord-545a502d472a47df8f18dd5330de196d

Source dataset

uspto-grants-2013_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08592578B2