Ethyl 4,4,4-trifluoroacetoacetate → HCID 178516152, compound

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Reaction Steps

Into a 250 mL flask was weighed 5.01 g of 4,4,4-trifluoro-3-oxo-butyric acid ethyl ester, 4.88 g of 2-chlorophenylhydrazine hydrochloride, and 100 mL of ethanol. The resulting solution was heated at 90-950C for 18 h then was concentrated in vacuo to remove ethanol. The residue was washed into a separatory funnel with ethyl acetate and 1 M HCl. The ethyl acetate was separated, washed with brine, was dried, and concentrated in vacuo. The residue was partially purified by silica gel flash chromatography (Jones Flashmaster, 70 g Silica gel, gradient elution from 100% hexanes to 20% ethyl acetate over 30 minutes). Appropriate fractions were combined and concentrated and product was precipitated by addition of excess hexanes. The solid precipitate was collected by filtration and was dried under high vacuum to afford the intermediate 2-(2-Chlorophenyl)-5-trifluoromethyl-2H-pyrazol-3-ol as a tan powder, yield: 3.73 g (52%). 1H NMR (DMSO-d6): δ 12.25 (br s, 1H), 7.72 (d, J=8 Hz, 1H), 7.5-7.65 (m, 3H), 5.94 (s, 1H).

Provenance & Evidence