反应详情

Di-tert-butyl dicarboxylate (9.58 mL, 41.7 mmol) and 4-dimethylaminopyridine (1.02 g, 0.34 mmol) were successively added to a tert-butanol solution (56 mL) of 7-methoxycarbonylheptanoic acid (1) (5.00 mL, 5.24 g, 27.8 mmol) at room temperature under the argon atmosphere, and the mixture was stirred at room temperature for 1 hour. A 0.2 N hydrochloric acid solution (20 mL) was added to the reaction solution to make the mixture weakly acidic, and the reaction solution was concentrated to about ⅓ volume, and extracted with chloroform (50 mL) three times. The organic layer was washed with saturated brine (50 mL), dried over sodium sulfate, and concentrated. The resulting brown oily crude product (6.5 g) was separated and purified by silica gel column chromatography (hexane:ethyl acetate=10:1) to obtain t-butyl-7-methoxycarbonylheptanoate (2) as a colorless liquid substance (5.58 g, 82%).

1. concentrationthe reaction solution was concentrated to about ⅓ volume
2. extractionextracted with chloroform (50 mL) three times
3. washThe organic layer was washed with saturated brine (50 mL)
4. dry with materialdried over sodium sulfate
5. concentrationconcentrated
6. customThe resulting brown oily crude product (6.5 g) was separated
7. custompurified by silica gel column chromatography (hexane:ethyl acetate=10:1)