反应详情

5-tert-Butoxycarbonylamino-2-methylpyridine (625 mg) in concentrated hydrochloric acid (3 mL) was stirred at room temperature for 50 minutes. Under cooling with ice with sodium chloride, sodium nitrite (228 mg) in water (1 mL) was added dropwise to the reaction mixture over a period of 10 minutes, followed by stirring for 10 minutes. Tin(II) chloride dihydrate (2.37 g) in concentrated hydrochloric acid (1.6 mL) was added dropwise to the reaction mixture over a period of 10 minutes, followed by stirring for 3 hours under cooling with ice. 2-Oxo-2-(1-oxoindan-2-yl)acetic acid ethyl ester (696 mg) obtained from Referential Example 62 in ethanol (20 mL) was added to the reaction mixture. The resultant mixture was refluxed under heat for 39 hours. Under cooling with ice, the reaction mixture was alkalinized with an aqueous solution of sodium hydroxide. Subsequently, the resultant mixture was partitioned between ethyl acetate and water. The organic layer was sequentially washed with water and saturated brine, and dried over sodium sulfate anhydrate. The mixture was subjected to filtration, and the solvent was evaporated under reduced pressure. The residue was purified through silica gel column chromatography (chloroform-acetone), to thereby give the title compound as crystals (340 mg, 35%).

1. additionwas added dropwise to the reaction mixture over a period of 10 minutes
2. stirringby stirring for 3 hours
3. temperatureunder cooling with ice
4. additionwas added to the reaction mixture
5. temperatureunder heat for 39 hours
6. temperatureUnder cooling with ice
7. customSubsequently, the resultant mixture was partitioned between ethyl acetate and water
8. washThe organic layer was sequentially washed with water and saturated brine
9. dry with materialdried over sodium sulfate anhydrate
10. filtrationThe mixture was subjected to filtration
11. customthe solvent was evaporated under reduced pressure
12. customThe residue was purified through silica gel column chromatography (chloroform-acetone)