反应详情

On a water separator, 21.90 g (106.0 mmol) of N-[(6-chloropyridin-3-yl)methyl]-2,2-difluoroethane-1-amine (III-1), 14.85 g (148.4 mmol) of tetronic acid and 183 mg (1.1 mmol) of 4-toluenesulphonic acid in 250 ml of toluene are heated under reflux for 2 hours. The reaction mixture is concentrated under reduced pressure, the residue is then taken up in ethyl acetate and the mixture is washed successively twice with 1 N aqueous hydrochloric acid, twice with 1 N aqueous sodium hydroxide solution and once with saturated sodium chloride solution. The organic phase is dried over sodium sulphate and concentrated under reduced pressure. Purification of the residue by column chromatography on silica gel (silica gel 60—Merck, particle size: 0.04 to 0.063 mm) using the mobile phase ethyl acetate gives 15.9 g (52% of theory) of 4-[[(6-chloropyridin-3-yl)methyl](2,2-difluoroethyl)amino]furan-2(5H)-one.

1. temperatureunder reflux for 2 hours
2. concentrationThe reaction mixture is concentrated under reduced pressure
3. washthe mixture is washed successively twice with 1 N aqueous hydrochloric acid, twice with 1 N aqueous sodium hydroxide solution and once with saturated sodium chloride solution
4. dry with materialThe organic phase is dried over sodium sulphate
5. concentrationconcentrated under reduced pressure
6. customPurification of the residue by column chromatography on silica gel (silica gel 60—Merck, particle size: 0.04 to 0.063 mm)