Hydrazine hydrate (1:1) → 4-[1-(3-Cyclopentyloxy-4-methoxy-phenyl)ethyl]-5-methylpyrazol-3-one

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of methyl 2-acetyl-3-(3-cyclopentyloxy-4-methoxyphenyl)-butanoate (362 mg, 1.08 mmol) in absolute ethanol (10 ml) at 0° C. was added hydrazine monohydrate (54 mg, 1.08 mmol) in one portion. The resulting solution was stirred at 0° C. for 45 minutes and then refluxed at 80° C. for 3 hours. Further hydrazine monohydrate (15.6 mg, 3.1×10−4 mol) was added and refluxing continued for a further 3 hours. After cooling to room temperature, the reaction mixture was concentrated in vacuo and purified by flash chromatography (SiO2; methylene chloride/ethanol/ammonia (97.5:2.5:0.25)) to afford the title compound as a white solid (76 mg).

Provenance & Evidence