Methylhydrazine → 3-Benzyl-1,5-dimethyl-1h-pyrazole-4-carboxylic acid methyl ester

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Reaction Steps

MeNHNH2 (0.42 mL. 7.9 mmol) is added to a solution of 2-acetyl-3-oxo-4-phenyl-butyric acid methyl ester (1.84 g, 7.85 mmol) in EtOH (15 mL) at RT. The mixture is stirred for 14 h at RT. The solvent is removed and crude material is purified by column chromatography using 10-25% EtOAc in hexane to afford 5-benzyl-1,3-dimethyl-1H-pyrazole-4-carboxylic acid methyl ester (less polar) and 3-benzyl-1,5-dimethyl-1H-pyrazole-4-carboxylic acid methyl ester (more polar).

Provenance & Evidence