反应详情

温度

20 °C

5-Amino-6-methyl-3-phenyl-1H-indazole can be obtained in the following way: 0.5 ml of water and 0.18 ml of an aqueous 12N hydrochloric acid solution are added to a solution of 0.53 g of 6-methyl-5-nitro-3-phenyl-1H-indazole in 30 ml of ethanol. The reaction mixture is then heated at the reflux of the solvent and 0.36 g of powdered iron are added in 2 steps. The reaction mixture is then stirred at the reflux of the solvent for 4.5 hours and is then cooled to a temperature in the region of 20° C. and treated with 50 ml of ice-cold water. The mixture is then basified with an aqueous 32% ammonium hydroxide solution, to a pH in the region of 11. After settling out, the aqueous phase is extracted with one times 50 ml then 2 times 25 ml of ethyl acetate. The organic extracts are pooled, dried over magnesium sulfate, filtered and then concentrated to dryness under reduced pressure (2 kPa) at a temperature in the region of 40° C. The residue thus obtained is purified by chromatography on a silica column (particle size 63-200 μm), eluting with a cyclohexane/ethyl acetate (75/25 by volume) mixture. The fractions containing the expected product are pooled and concentrated to dryness under reduced pressure (2 kPa) at a temperature in the region of 40° C. 0.4 g of 5-amino-6-methyl-3-phenyl-1H-indazole is thus obtained in the form of a beige crystalline solid melting at 133° C.

1. temperatureThe reaction mixture is then heated at the
2. additionare added in 2 steps
3. temperaturereflux of the solvent for 4.5 hours
4. extractionthe aqueous phase is extracted with one times 50 ml
5. dry with materialdried over magnesium sulfate
6. filtrationfiltered
7. concentrationconcentrated to dryness under reduced pressure (2 kPa) at a temperature in the region of 40° C
8. customThe residue thus obtained
9. customis purified by chromatography on a silica column (particle size 63-200 μm)
10. washeluting with a cyclohexane/ethyl acetate (75/25 by volume) mixture
11. additionThe fractions containing the expected product
12. concentrationconcentrated to dryness under reduced pressure (2 kPa) at a temperature in the region of 40° C