反应详情

In a separable flask equipped with a Dean-Stark trap, maleimidoacetic acid (reagent grade) (31.0 g, 0.2 mol), p-toluenesulfonic acid (reagent grade) (5.2 g, 0.03 mol), and toluene (reagent grade) (300 ml) were charged. Then, the mixture was stirred and reacted under reduced pressure at 80° C. for 1 hour with dropwise addition of n-pentanol (reagent grade) (17.6 g, 0.2 mol). After the dropwise addition, the mixture was stirred for another 4 hours for allowing the reaction to be continued. During the reaction, the water formed was removed with the Dean-Stark trap. After the reaction, toluene (300 ml) was added and the mixture was washed three times with ion-exchanged water (100 ml). Then, the organic phase obtained was collected and subjected to removal of the toluene by evaporation using an evaporator and a vacuum dryer to give n-pentyl maleimidoacetate (43.5 g). (Yield: ca. 91%. The absence of maleimidoacetic acid and n-pentanol was verified by GPC measurement. The presence of n-pentyl maleimidoacetate was verified by 1H-NMR measurement using DMSO-d6. This compound is referred to hereinafter as Compound A1).

1. additionwere charged
2. additionAfter the dropwise addition
3. stirringthe mixture was stirred for another 4 hours
4. customthe reaction
5. customDuring the reaction
6. customwas removed with the Dean-Stark trap
7. customAfter the reaction, toluene (300 ml)
8. additionwas added
9. washthe mixture was washed three times with ion-exchanged water (100 ml)
10. customThen, the organic phase obtained
11. customwas collected
12. customsubjected to removal of the toluene by evaporation
13. customan evaporator