Step 3: To a solution of dichloromethane (50 mL) of the intermediate (6.0 g, 47.6 mmol) obtained in Step 2 was slowly added oxalyl chloride (6.12 mL, 71.4 mmol) and a catalytic amount of N,N-dimethylformamide (0.5 mL) at 0 °C. The reaction mixture was stirred at room temperature for 2 hours. Upon completion of the reaction, the solvent was removed by concentration under reduced pressure and the resulting residue was redissolved in dichloromethane. Ammonia was passed into the solution for 30 min at 0°C. Subsequently, the reaction mixture was concentrated again under reduced pressure and the residue was suspended in tetrahydrofuran (50 mL) and filtered. The filtrate was concentrated under reduced pressure to afford the target product 1-methyl-1H-pyrazole-3-carboxamide (3.5 g, 59% yield).LC-MS (Method 3): m/z [M + H]+ = 126 (theoretical molecular weight = 125.13); retention time R = 0.76 min.
