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

Participants

Reaction Conditions

Reaction Steps

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).

Provenance & Evidence