反应详情

4-{[5-(Methylsulfonyl)pyridin-2-yl]oxy}-2-(tetrahydro-2H-pyran-4-yloxy)aniline (25.7 g) was suspended in a mixed solvent of acetonitrile (50 mL)-ethanol (100 mL), and concentrated hydrochloric acid (21 mL) was added at 10° C. To a mixture was added dropwise sodium nitrite (5.8 g) dissolved in water (15 mL) at −5° C., and the mixture was stirred at −10° C. to −5° C. for 1 hr. The mixture was added to a mixture of ethyl 2-methyl-3-oxobutanoate (11.2 mL), potassium hydroxide (85%, 8.6 g), water (70 mL), and ethanol (100 mL) at −40 to −30° C. and the mixture was stirred at −28° C. for 30 min. To the reaction solution was added 1M hydrochloric acid (110 mL), and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over magnesium sulfate, filtered and concentrated under reduced pressure. The obtained crude product was subjected to silica gel column chromatography (ethyl acetate:hexane=30:70 to 100:0, volume ratio) to give the title compound (25.8 g, yield 77%) as a yellow amorphous solid.

1. additionwas added at 10° C
2. stirringthe mixture was stirred at −28° C. for 30 min
3. extractionthe mixture was extracted with ethyl acetate
4. washThe organic layer was washed with saturated brine
5. dry with materialdried over magnesium sulfate
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure
8. customThe obtained crude product