[CH:1]([N:4]1[CH:8]=[CH:7][CH:6]=[N:5]1)([CH3:3])[CH3:2].[N+:9]([O-])([O-:11])=[O:10].[K+]>OS(O)(=O)=O>[CH:1]([N:4]1[CH:8]=[C:7]([N+:9]([O-:11])=[O:10])[CH:6]=[N:5]1)([CH3:3])[CH3:2]To a solution of 1-isopropyl-1 H-pyrazole (5 g, 45.5 mmol) in conc.H2SO4 (50 mL) was added KNO3 (5.0 g, 50 mmol) portion wise at 0° C. After the addition, the resulting mixture was heated to 50 0° C. for 8 h. The reaction mixture was cooled to room temperature and poured into ice water, and the mixture was extracted with EtOAc. The combined organics were washed with saturated Na2CO3 solution, brine, and were dried over Na2SO4, and concentrated in vacuo. Chromatography on silica gel provided 1-isopropyl-4-nitro-1 H-pyrazole (3.2 g, 46% yield). 1H NMR (400 MHz, DMSO-d6): δ 8.99 (s, 1 H), 8.32 (s, 1 H), 4.65 (m, 1 H), 1.51 (d, J=6.8 Hz, 6H).
Loading…