反应详情

A solution of ethyl 4-hydroxy-6,7,8-trifluoroquinoline-3-carboxylate (59.0 g) and POCl3 (500 ml) was refluxed for 8 h. Excess POCl3 was distilled off, the residue was removed into the mixture of ice and water. Solid NaHCO3 was added into the mixture to pH 7˜8 and the precipitated solid was isolated by filtration. The crude was recrystallized by toluene to afford the title compound (41.3 g, 65.6% yield), mp: 110-112° C.

1. distillationExcess POCl3 was distilled off
2. customthe residue was removed into the mixture of ice and water
3. additionSolid NaHCO3 was added into the mixture to pH 7˜8
4. customthe precipitated solid was isolated by filtration
5. customThe crude was recrystallized by toluene