(2,6-Dichlorophenyl)hydrazine monohydrochloride → 2-(2,6-Dichloro-phenyl)-4-isobutyl-5-methyl-2H-pyrazole-3-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

A mixture of 3-acetyl-2-methoxyimino-5-methyl-hexanoic acid ethyl ester (1 g, 4.1 mmol), 2,6-dichlorophenylhydrazine hydrochloride (1.76 g, 8.2 mmol) in glacial acetic acid (10 mL) and 2-methoxy-ethanol (5 mL) is stirred at 105° C. for 3 hours. The reaction is concentrated and the residue is partitioned between EtOAc and 1N HCl. The organic layer is concentrated and purified by column chromatography (0-20% EtOAc in hexanes) to give the title product as an oil, 1.1 g (76%).

Provenance & Evidence