35691-93-1

603-69-0

35691-93-1

General procedure for the synthesis of ethyl 3,5-dimethyl-1H-4-pyrazolecarboxylate from ethyl bisacetoacetate: To a solution of ethyl bisacetoacetate (4.6 g, 26.7 mmol) in ethanol (50 mL) was added hydrazine hydrochloride (1.8 g, 26.7 mmol). The reaction mixture was heated to reflux and kept for 2 hours. Upon completion of the reaction, the solvent was removed by distillation under reduced pressure. The resulting residue was washed with ethyl acetate to afford ethyl 3,5-dimethyl-1H-4-pyrazolecarboxylate as a colorless solid (3.1 g, 69% yield), which was pure enough to be used directly in the subsequent reaction.