反应详情

温度

77.5 °C

(4-Aminophenoxy)-acetic acid 2-[2-(4-aminophenoxy)-acetoxy]-ethyl ester 25 (5 g, 14.3 mmol) were dissolved in dry dioxane (80 ml) under nitrogen atmosphere and cooled to below 20° C. A solution of triphosgene (7 g, 23.6 mmol) in dry dioxane (20 ml) was added drop wise. The mixture was heated slowly to 75-80° C. and maintained for 2½ hours. The condenser was then arranged for distillation and solvent removed by distillation at atmospheric pressure until the volume of the reaction mixture was reduced to approximately one third. Fresh dry dioxane (50 ml) was added and the solvent was distilled off under vacuum. The residue was re-evaporated two times from dry dioxane to give crude 26. Crude 26 was recrystallised from a mixture of toluene:hexane (1:3) to give pure 26 (2.6 g, 44.2%) as a white powder with an m.p. between 96-98° C.

1. temperaturecooled to below 20° C
2. temperaturemaintained for 2½ hours
3. distillationThe condenser was then arranged for distillation and solvent
4. customremoved by distillation at atmospheric pressure until the volume of the reaction mixture
5. additionFresh dry dioxane (50 ml) was added
6. distillationthe solvent was distilled off under vacuum
7. customThe residue was re-evaporated two times from dry dioxane
8. customto give crude 26
9. customCrude 26 was recrystallised from a mixture of toluene:hexane (1:3)