p-Toluenesulfonic acid → HCID 68888626, compound

Participants

Reaction Conditions

Reaction Steps

3-Fluoro-2-methyl-phenylhydrazine (8.4 g, 0.06 mol) was dissolved in ethanol and the solution cooled to 0° C. (ice-bath). Ethyl pyruvate (6.9ml, 0.062 mol) was added dropwise and the solution stirred 15 h at room temperature. The solvent was evaporated under reduced pressure, and the residue stirred with hexane. The mixture of hydrazones that formed upon cooling in an ice-bath was filtered and dried under vacuum. Yield: 9.1 g, 64%. The hydrazone mixture (7.6 g,0.032 mol) was dissolved in toluene (45 ml), anhydrous p-toluenesulfonic acid (8.2 g, 0.048 mol) added and the mixture heated 1 h at reflux. The mixture was cooled to room temperature, poured into half-saturated aqueous sodium hydrogen carbonate and extracted twice with ethyl acetate. The combined organic phases were washed with brine, dried over magnesium sulfate and evaporated. The residue was purified by column chromatography on silica gel (8:1 to 6:1 hexane/ethyl acetate eluant) to afford the product as a light brown solid (1.68 g, 24%). EI MS: 221.1 (M+)

Provenance & Evidence