Phenylhydrazine → 1-Phenyl-1H-pyrazole-3,5-diamine

Participants

Reaction Conditions

Reaction Steps

Triethylamine (6 ml) was added over 5 minutes to a stirred suspension of diethyl malonimidate dihydrochloride (5 g) in ethanol (50 ml). Phenylhydrazine (2.1 ml) was added, then the mixture was stirred at ambient temperature for 4 hours and at 95° C. for 30 minutes. The solvent was removed in vacuo, and the residue was partitioned between ethyl acetate (100 ml) and water (50 ml). The organic layer was separated, washed with water (50 ml), dried (MgSO4), and the solvent was removed in vacuo. The residue was purified by flash chromatography over silica using a 19:1 mixture of dichloromethane and methanol as eluant, appropriate fractions were combined, and the solvents were removed in vacuo to give 3,5-diamino-1-phenylpyrazole as a red-brown oil (0.76 g).

Provenance & Evidence