Dimethylformamide → 4-nitro-1H-pyrazole-5-carboxamide

4-Nitro-2H-pyrazole-3-carboxylic acid (2.72 g, 17.4 mmol) was added to a solution of oxalyl chloride (2.42 mL, 27.7 mmol) and N,N-dimethylformamide (80 μL) in dichloromethane (45 mL) and the reaction mixture stirred at room temperature for 2 hours. The reaction mixture was concentrated in vacuo and azeotroped from dichloromethane (3×100 mL). The crude product was dissolved in tetrahydrofuran, cooled in an ice bath, and treated with 0.880 ammonia solution (20 mL). The reaction mixture was stirred at room temperature for 18 hours then concentrated in vacuo and the residue partitioned between dichloromethane (300 mL) and water (100 mL). The organic layer was separated, dried over magnesium sulphate and concentrated in vacuo to yield the title product. LRMS ES+m/z 157 [MH]+