Triethylamine → ethyl 1-butyl-5-methyl-1H-pyrazole-3-carboxylate

Participants

Reaction Steps

Butylhydrazine oxalate (25 g, 140 mmol) was added over a period of 15 minutes to a solution of ethyl 2,4-dioxovalerate (22.2 g, 140 mmol) and triethylamine (210 mmol) in ethanol (140 mL). The resulting solution was stirred overnight at ambient temperature and concentrated under reduced pressure. Hexane was added, and an insoluble solid was removed by filtration. The hexane was removed under reduced pressure; the residue was purified by chromatography on a HORIZON HPFC system (65I cartridge, eluting with hexanes/ethyl acetate in a gradient from 80:20 to 45:55) to provide 18.1 g of ethyl 1-butyl-5-methyl-1H-pyrazole-3-carboxylate as a pale yellow oil.

Provenance & Evidence