5-Amino-4-carbethoxy-1-phenylpyrazole

100-63-0

94-05-3

16078-71-0

General procedure for the synthesis of ethyl 5-amino-1-phenylpyrazole-4-carboxylate from phenylhydrazine and ethyl ethoxymethylcyanoacetate: ethyl 2-cyano-3-ethoxyacrylate (1.5 g, 8.9 mmol, 1.0 equiv.) was dissolved in ethanol (10 mL), followed by the addition of N,N-diisopropylethylamine (0.74 mL, 9.8 mmol, 1.1 equiv.) and phenylhydrazine (0.96 mL, 9.8 mmol, 1.1 equiv.). The reaction mixture was heated to 85 °C and stirred for 12 hours. Upon completion of the reaction, the mixture was concentrated to dryness and the residue was dissolved in a minimal amount of dichloromethane and purified by silica gel column chromatography (eluent: 20-30% ethyl acetate in hexane solution) to afford ethyl 5-amino-1-phenyl-1H-pyrazole-4-carboxylate (2.0 g, 96% yield) as an orange solid.MS (EI) m/z: 232 [M + H]+.