Water → Methyl 1-(4-methylphenyl)-pyrazole-5-carboxylate

Participants

Reaction Conditions

Reaction Steps

12.5 g of p-tolylhydrazine in 150 ml of glacial acetic acid were added to a solution of 16 g of methyl 4-ethoxy-2-oxobut-3-enoat in 100 ml of glacial acetic acid at 50° C. The mixture was stirred at 100° C. for 5 hours, poured into 1 liter of water, and extracted twice with 100 ml of ethyl acetate. The organic phase was washed with saturated NaHCO3 solution and subsequently with water, and dried. After evaporating in a water-pump vacuum, the mixture was separated by distillation in a high vacuum. 4.1 g of methyl 1-(4-methylphenyl)-pyrazole-5-carboxylate of boiling point 116°-120° C./0.01 torr (example 8) and 5.3 g of methyl 1-(4-methylphenyl)-pyrazole-3-carboxylate of boiling point 138°-142° C./0.01 torr were obtained. The compounds were characterized by 1H NMR spectroscopy.

Provenance & Evidence