反应详情

1-((2-M ethoxy-6-methylpyridin-3-yl)methyl)-4-nitro-3-vinyl-1H-indazole (395 mg, 1.22 mmol) and palladium hydroxide on carbon (171 mg, 0.244 mmol; 20%) were added to a hydrogenation flask. Methanol (6 mL) was added along with a small amount of dichloromethane. The reaction flask was evacuated and purged with nitrogen prior to being shaken on a Parr apparatus under an atmosphere of hydrogen at 40 psi for 7 hours. The mixture was filtered through Celite, rinsing with methanol and the filtrated was concentrated under reduced pressure. The material was purified using preparative thin layer chromatography on silica, eluting with 10% methanol in dichloromethane containing 0.5% ammonium hydroxide solution. Further purification was carried out using column chromatography on silica, eluting with 1% methanol in dichloromethane containing 0.5% ammonium hydroxide solution to provide 3-ethyl-1-((2-methoxy-6-methylpyridin-3-yl)methyl)-1H-indazol-4-amine (108 mg). Some material was isolated where the nitro group had not been completely reduced (186 mg). This material was dissolved in ethanol (3 mL). Iron powder (318 mg; 5.70 mmol) and ammonium chloride (15.2 mg; 0.285 mmol) were added and the mixture was heated at reflux for 1 hour. The mixture was allowed to cool and filtered through glass fiber filter paper rinsing with ethanol. The solution was concentrated under reduced pressure and purified using preparative thin layer chromatography, eluting with 2% methanol in dichloromethane containing 0.25% ammonium hydroxide solution to provide an additional 108 mg of 3-ethyl-1-((2-methoxy-6-methylpyridin-3-yl)methyl)-1H-indazol-4-amine.

1. customThe reaction flask was evacuated
2. custompurged with nitrogen
3. filtrationThe mixture was filtered through Celite
4. washrinsing with methanol
5. concentrationthe filtrated was concentrated under reduced pressure
6. customThe material was purified
7. washeluting with 10% methanol in dichloromethane containing 0.5% ammonium hydroxide solution
8. customFurther purification
9. washeluting with 1% methanol in dichloromethane containing 0.5% ammonium hydroxide solution