反应详情

Acetic anhydride (0.85 ml, 9.01 mmol), n-butylammonium bromide (0.0502 g, 0.156 mmol) and potassium acetate (0.587 g, 5.98 mmol) were added to a solution of methyl 4-(acetylamino)-2,5-dimethylbenzoate (0.661 g, 2.99 mmol) in ethyl acetate (5 ml), followed by adding thereto a solution of isoamyl nitrite (0.0458 g, 3.91 mmol) in ethyl acetate (2 ml), and the resulting mixture was stirred for 8 hours with heating under reflux. Water was added thereto, followed by extraction with ethyl acetate (three times), and the extract solution was dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure and the resulting residue was purified by a silica gel column chromatography (hexane/ethyl acetate=5/1 to 1/1). The solid thus obtained was suspended in hexane and stirred to be washed, and then it was collected by filtration and dried under reduced pressure to obtain methyl 1-acetyl-6-methyl-1H-indazole-5-carboxylate (0.0731 g, 11%).

1. additionby adding
2. temperaturewith heating
3. temperatureunder reflux
4. extractionfollowed by extraction with ethyl acetate (three times)
5. dry with materialthe extract solution was dried over anhydrous magnesium sulfate
6. distillationThe solvent was distilled off under reduced pressure
7. customthe resulting residue was purified by a silica gel column chromatography (hexane/ethyl acetate=5/1 to 1/1)
8. customThe solid thus obtained
9. washto be washed
10. filtrationit was collected by filtration
11. customdried under reduced pressure