Hydrochloric Acid → 1-(4-Methoxybenzyl)-1H-pyrazole-3,5-dicarboxylic Acid

Participants

Reaction Steps

Diethyl 3,5-pyrazoledicarboxylate (400 mg, 1.9 mmol, 1.0 eq.) and K2CO3 (391 mg, 2.8 mmol, 1.5 eq.) were dissolved in DMF (1.50 mL) with stirring. p-Methoxybenzyl chloride (295 mg, 1.9 mmol, 1.0 eq.) was added and the mixture was stirred at room temperature overnight. EtOAc (20 mL) and water (20 mL) were added. The organic fractions were separated and washed with water (20 mL) and saturated aqueous NaCl (20 mL), dried over Na2SO4, The solvent was removed to yield a clear oil, which was purified by flash chromatography (0-40% EtOAc/hexanes over 20 minutes). The fractions were combined and the solvent evaporated. THF (7 mL) and 2M aqueous NaOH (3.8 mL, 4.0 eq.) was added and the mixture stirred at room temperature overnight. The mixture was acidified with 1N HCl to pH˜4. The precipitate was filtered off and dried under vacuum to yield the title compound as a white solid. (440 mg).

Provenance & Evidence