The general procedure for the synthesis of 3-nitro-1H-pyrazole from 1-nitropyrazole is as follows:
Step A: 1-nitropyrazole (3.45 g, 30.5 mmol) was mixed with benzonitrile (33 mL) and heated with stirring at 180 °C for 3 hours. Upon completion of the reaction, the mixture was cooled to room temperature, diluted with hexane and stirring was continued for 20 min at room temperature. The precipitated solid was collected by filtration to afford 3-nitro-1H-pyrazole as a tan solid (3.16 g, 91% yield).
Product characterization data: 1H NMR (300 MHz, DMSO-d6) δ 13.94 (br s, 1H), 8.03 (d, J = 2.4 Hz, 1H), 7.03 (t, J = 2.4 Hz, 1H).
