Hydrochloric Acid → ethyl 3-hydroxy-1H-pyrazole-4-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of sodium ethoxide (20.8 g, 0.31 mol) and diethyl ethoxymethylenemalonate (20 mL, 0.10 mol) in ethanol (400 mL), was added hydrazine monohydrate (10.0 mL, 0.20 mol) with cooling in an ice-cold water bath. The mixture was then heated at 80° C. for 3 h. The resulting mixture was diluted with water (200 mL) and neutralized with 10M HCl solution until pH 6. The mixture was extracted several times with chloroform. The aqueous layer was acidified to pH 2 and extracted again with chloroform. The combined organic layers were dried (Na2SO4) and concentrated to a solid which was washed with methanol and ether and dried to give the product (13.2 g, 80%) as a solid. 1H NMR (400 MHz, DMSO-d6) δ7.89 (s, 1H), 4.15 (q, 211, J=7.12 Hz), 1.23 (t, 3H, J=7.11 Hz).

Provenance & Evidence