Sulfuric Acid → 1-[(4-Methoxy)phenyl]-5-(methoxycarbonyl)pyrazole-3-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of dimethyl 1-[(4-methoxy)phenyl]pyrazole-3,5-dicarboxylate (32.7 g, 110 mmol) in 50 mL of dioxane and 100 mL of water was added concentrated sulfuric acid (1.50 mL, 28.2 mmol). The resulting solution was stirred at 100° C. for 18 h and then cooled to room temperature. The reaction was made basic with potassium carbonate and then extracted with ether to remove unreacted diester. The aqueous layer was acidified with HCl and was extracted twice with ethyl acetate. The combined organics were washed with brine, dried (MgSO4) and concentrated to afford 19.2 g (63%) of the title compound along with 5.0 g (15%) of unreacted starting material. The title compound was used without further purification. LRMS (ES−): 274.9 (M−H)−.

Provenance & Evidence