Triethylamine → N-(4-cyano-1-isopropyl-1H-pyrazol-5-yl)-4-nitrobenzamide

A mixture of crude 5-amino-1-isopropyl-1H-pyrazole-4-carbonitrile (0.72 g, 4.5 mmol maximum) and 4-nitrobenzoylchloride (1.3 g, 6.8 mmol) in dichloromethane (20 mL) was treated successively with triethylamine (1.8 mL, 14 mmol) and 4-N,N-dimethylaminoaniline (DMAP, 55 mg, 10 mol %). The mixture was heated to reflux (oil bath) for one hour and then allowed to cool to room temperature. The mixture was then concentrated to dryness under reduced pressure. The residue was dissolved in pyridine (20 mL). Water was added, followed by concentrated aqueous ammonium hydroxide (5 mL). The reaction vessel was swirled manually and then left overnight at room temperature. The mixture was concentrated to dryness under reduced pressure. The residue was partitioned between ethyl acetate and water. The aqueous phase was extracted three times with ethyl acetate. The combined extracts were washed twice with saturated aqueous sodium hydrogen carbonate solution and once each with 0.25 M aqueous hydrochloric acid and saturated aqueous sodium chloride solution. Drying over anhydrous magnesium sulfate was followed by filtration and then concentration under reduced pressure to provide N-(4-cyano-1-isopropyl-1H-pyrazol-5-yl)-4-nitrobenzamide as a dark yellow solid (1.3 g, 100%). MS (ES+): 299.6, 299.9 (M+H)+