反应详情

Trifluoroacetic acid (5 ml) was added to a dichloromethane solution (5 ml) of tert-butyl 4-{1-(2-tetrahydropyranyl)-1H-indazol-5-ylamino}benzoate (205 mg, 0.521 mmol), and the resulting mixture was stirred at room temperature for 3 hours. The mixture was added dropwise to saturated aqueous sodium hydrogencarbonate solution/ethyl acetate and then extracted with ethyl acetate. The extract solution was washed with a saturated aqueous sodium chloride solution, dried over sodium sulfate, and then distilled under reduced pressure to remove the solvent, whereby a crude product was obtained. The crude product was washed by the addition of chloroform containing a small amount of methanol, and then was collected by filtration to obtain 4-(1H-indazole-5-ylamino)benzoic acid (46 mg, 35%).

1. extractionextracted with ethyl acetate
2. washThe extract solution was washed with a saturated aqueous sodium chloride solution
3. dry with materialdried over sodium sulfate
4. distillationdistilled under reduced pressure
5. customto remove the solvent, whereby a crude product
6. customwas obtained
7. washThe crude product was washed by the addition of chloroform containing a small amount of methanol
8. filtrationwas collected by filtration