反应详情

5 g (26.57 mmol) of 2-methyl-4-oxo-4H-chromene-8-carbaldehyde, 3.4 ml (26.57 mmol) of ethyl 3-oxobutanoate, 1.9 ml (33.21 mmol) of acetic acid and 263 μl (2.66 mmol) of piperidine in 50 ml of anhydrous dichloromethane are stirred under reflux with a water trap for 24 h. After cooling, the solution is diluted with dichloromethane (50 ml) and washed successively with saturated sodium bicarbonate solution and saturated sodium chloride solution. The organic phase is dried over magnesium sulfate and concentrated. The residue is recrystallized from isopropanol. 7.63 g (91% of theory) of the title compound are obtained as an E/Z mixture.

1. temperatureunder reflux with a water trap for 24 h
2. temperatureAfter cooling
3. washwashed successively with saturated sodium bicarbonate solution and saturated sodium chloride solution
4. dry with materialThe organic phase is dried over magnesium sulfate
5. concentrationconcentrated
6. customThe residue is recrystallized from isopropanol