反应详情

A solution of 3-methylpyrazole (1.96 mL, 24.0 mmol) in sulfuric acid (15 mL) was cooled to −5° C. and potassium nitrate (1.1 eq) was added portion-wise. The reaction was warmed to rt and stirred for 16 h. The mixture was cooled to 0° C. and neutralized with ammonium hydroxide solution. The resulting solid was filtered and air-dried to give 3-methyl-4-nitro-1H-pyrazole. To a solution of 3-methyl-4-nitropyrazole (300 mg, 2.6 mmol), potassium carbonate (2 eq) and the alkylating reagent (1.1 eq) in acetonitrile (10 mL) was heated at 60° C. for 18 h. After cooling to rt the mixture was diluted with EtOAc and washed with water. The organic phase was collected, dried (MgSO4) and concentrated in vacuo. The crude residue was dissolved in methanol (10 mL), palladium on carbon (50 mg) was added and the reaction was stirred under a balloon of hydrogen for 18 h. The resulting mixture was filtered through Celite and the filtrate concentrated in vacuo to give the desired product.

1. filtrationThe resulting solid was filtered
2. customair-dried