反应详情

52.4 g (0.15 mol) of 1-benzyl-3-(5-carboxy-2-furyl)indazole, potassium salt, were initially charged in 1250 ml of toluene, and after addition of 200 ml of abs. ethanol and 50 ml of conc. sulfuric acid the mixture was stirred under reflux on a water separator. After 3 hours, the mixture was concentrated using a rotary evaporator, the oil that remained was taken up in water/ethyl acetate and the aqueous phase was separated off. The organic phase was washed with water and 7.5% strength NaHCO3 solution, dried with sodium sulfate and concentrated. The residue was recrystallized from isopropanol. This gave 37.8 g (73%) of the title compound. m.p.: 98-99° C.

1. additionafter addition of 200 ml of abs
2. concentrationthe mixture was concentrated
3. customa rotary evaporator
4. customthe aqueous phase was separated off
5. washThe organic phase was washed with water and 7.5% strength NaHCO3 solution
6. dry with materialdried with sodium sulfate
7. concentrationconcentrated
8. customThe residue was recrystallized from isopropanol