反应详情

温度

0 °C

Following generally the procedure reported by Organic Synthesis 1955, Coll. Vol. 3, 660; 1940, 20, 73, 2-ethyl-5-nitroaniline (1.021 g, 6.14 mmol) was dissolved in glacial acetic acid (40 ml) and the mixture was cooled to 0° C. A solution of sodium nitrite (1 eq, 424 mg) in water (1 ml) was added all at once. Stirring was continued for 15 minutes at 25° C. After 3 hours, residual solids were filtered off and discarded, and the filtrate was allowed to stand for 3 days at room temperature. The solution was concentrate in vacuo, and the residue was diluted with 2 ml of water and stirred vigorously. The solid product was filtered and washed thoroughly with cold water, dried and purified by flash chromatography (4:1 hexanes/ethyl acetate) to give 3-methyl-6-nitro-1H-indazole (436 mg, 40.5%) as a solid.

1. customreported by Organic Synthesis 1955, Coll
2. waitAfter 3 hours
3. filtrationresidual solids were filtered off
4. waitto stand for 3 days at room temperature
5. concentrationThe solution was concentrate in vacuo
6. additionthe residue was diluted with 2 ml of water
7. stirringstirred vigorously
8. filtrationThe solid product was filtered
9. washwashed thoroughly with cold water
10. customdried
11. custompurified by flash chromatography (4:1 hexanes/ethyl acetate)