Hydrochloric Acid → Methyl 4-benzyloxy-3-carboxy-1H-pyrazole-5-carboxylate

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Reaction Conditions

Reaction Steps

Dimethyl 4-benzyloxy-1H-pyrazole-3,5-dicarboxylate (25 g, 86 mmol) was dissolved in N,N-dimethylhydrazine (75 mL) and the stirred mixture heated to reflux under nitrogen atmosphere for 30 hours. The solvent was removed in vacuo to give a white solid. The residue was dissolved in water (200 mL), 1N HCl (75 mL), and ethyl acetate (100 mL). The mixture was stirred and warmed to 35° C. until all the solids had dissolved. The layers were then separated and the aqueous layer was extracted with more ethyl acetate (3×100 mL). The combined organic extracts were dried over Na2SO4, filtered, and concentrated under reduced pressure to give the product as a white solid. 1H NMR (400 MHz, d6-DMSO) δ 13.2 (br s, 1H), 7.3-7.45 (m, 5H), 5.09 (s, 2H), 3.81 (s, 3H); ES MS (M+1)=277.

Provenance & Evidence