1,4-Dioxane → HCID 117716656, compound

Participants

Reaction Conditions

Reaction Steps

(4-Aminophenoxy)-propionic acid 2-{2-[2-(4-aminophenoxy)-propionyloxy]-ethoxy}-ethyl ester (217 g) was dissolved in dry 1,4-dioxane (2 L) under nitrogen atmosphere. The reaction mixture was cooled down to below 10° C. A solution of triphosgene (253 g) in dry 1,4-dioxane (600 ml) was added. The mixture was heated slowly to 80° C. and maintained at that temperature for 2 hours. The condenser was then arranged for distillation and solvent removed by distillation under atmospheric pressure until the volume of the reaction mixture had been reduced to approximately one third. Fresh dry 1,4-dioxane (600 ml) was added. Solvents were distilled off under vacuum. The residue was re-evaporated two times from dry 1,4-dioxane (1200 ml). Dry toluene (600 ml) and charcoal (50 g) was added. The solution was filtered hot and toluene was distilled off under vacuum to give pure (4-isocyanato-phenoxy)-propionic acid 2-{2-[2-(4-isocyanato-phenoxy)-propionyloxy]-ethoxy}-ethyl ester (165 g) as a light yellow syrup. The product was characterized by 1H NMR (CDCl3) δ 1.65 (d, 3H, CH3), 3.65 (t, 2H, CH2), 4.30 (t, 2H, CH2), 4.75 (q, 1H, CH), 6.80 (d, 2H, Ar), 7.00 (d, 2H, Ar).

Provenance & Evidence