Reacción #2045043

Ecuación de reacción

2-(4-Aminophenoxy)propionic acid-2-[2-(4-aminophenoxy)acetoxy]ethyl ester

dioxane

triphosgene

dioxane

→

57

Rendimiento 37.2%

2-(4-Isocyanatophenoxy)propionic acid-2-[2-(4-isocyanatophenoxy)acetoxy]ethyl ester

Rendimiento 37.2%

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturaand cooled below 20° C
2. 2
   Temperaturamaintained for 3 hrs
3. 3
   workup.DISTILLATIONThe condenser was arranged for distillation and solvent
4. 4
   Otroremoved by distillation at one atm. until the volume of the reaction mixture
5. 5
   workup.ADDITIONFresh dry dioxane (50 ml) was added
6. 6
   workup.DISTILLATIONsolvents distilled off under vacuum
7. 7
   OtroThe residue was re-evaporated twice from dry dioxane

Procedimiento

2-(4-Aminophenoxy)propionic acid-2-[2-(4-aminophenoxy)acetoxy]ethyl ester 56 (5.2 g, 13.9 mmol) was dissolved in dry dioxane (80 ml) under nitrogen atm. and cooled below 20° C. A solution of triphosgene (7 g, 23.6 mmol) in dry dioxane (20 ml) was added dropwise. The mixture was heated slowly to 75-80° C. and maintained for 3 hrs. The condenser was arranged for distillation and solvent removed by distillation at one atm. until the volume of the reaction mixture was reduced to approx. one third. Fresh dry dioxane (50 ml) was added and solvents distilled off under vacuum. The residue was re-evaporated twice from dry dioxane to give 57 (2.2 g, 37.2%) as a light yellow syrup.

Fuente