反应详情

2.85 g (15 millimoles) of ethyl 4-(chlorocarbonyloxy)-2-butynoate obtained in the first step of Example VI-9 was dissolved in 20 ml of dichloromethane, and 9 ml of a dichloromethane solution containing 3.1 ml (24 millimoles) of N-methylbenzylamine was rapidly added under cooling with ice. The mixture was reacted for 1 hour under stirring and cooling with ice. The reaction mixture was poured into ice water, adjusted to pH 2 with dilute hydrochloride acid and subjected to extraction treatment. The dichloromethane extraction solution was dried over sodium sulfate and then concentrated under reduced pressure. The residue was purified by silica gel column chromatography (with use of 30 g of silica gel). The desired fraction eluted by hexane-benzene (1:0→3:1), was collected and concentrated under reduced pressure, whereby 1.18 g (yield: 28.5%) of colorless oily ethyl 4-(N-benzyl-N-methylcarbamoyloxy)-2-butynoate was obtained.

1. additionwas rapidly added
2. temperatureunder cooling with ice
3. customThe mixture was reacted for 1 hour
4. temperaturecooling with ice
5. extractionsubjected to extraction treatment
6. extractionThe dichloromethane extraction solution
7. dry with materialwas dried over sodium sulfate
8. concentrationconcentrated under reduced pressure
9. customThe residue was purified by silica gel column chromatography (with use of 30 g of silica gel)
10. washThe desired fraction eluted by hexane-benzene (1:0→3:1)
11. customwas collected
12. concentrationconcentrated under reduced pressure