(2-Methoxyphenyl)hydrazine monohydrochloride → 5-Isopropyl-1-(2-methoxy-phenyl)-1H-pyrazole-3-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

2-Methoxyphenylhydrazine (14.07 g, 81 mmol) in EtOH (100 mL) was added dropwise to a refluxing solution of 5-methyl-2,4-dioxo-hexanoic acid ethyl ester (10 g, 53.7 mmol) in toluene (100 mL), under an argon atmosphere. The reaction mixture was stirred for 18 h at 100° C., allowed to cool to rt, concentrated, diluted with a saturated aqueous solution of sodium bicarbonate (250 mL), and extracted with EtOAc. The organic extracts were washed with a saturated aqueous solution of sodium bicarbonate, dried (Na2SO4), filtered, and concentrated. The residue was purified by silica gel column chromatography (hexane/EtOAc, 95:5→7:3) to provide 10.1 g of the title compound. tR: 1.11 min (LC-MS 4);

Provenance & Evidence