1,4-Dioxane → HCID 90308342, compound

Participants

Reaction Conditions

Reaction Steps

(4-Aminophenoxy)-acetic acid 2-{2-[2-(4-aminophenoxy)-acetoxy]-ethoxy}-ethyl ester (200 grams, 495 mmoles) was dissolved in dry 1,4-dioxane (2000 ml) under nitrogen atmosphere and cooled to below 10° C. A solution of triphosgene (250 grams, 842.45 mmoles) 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 the solvent was removed by distillation at 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 and distilled off under vacuum. The residue was re-evaporated two times from dry 1,4-dioxane (1.2 L), then dry toluene (600 ml) and charcoal (20 g) were added. The solution was filtered hot, and toluene was distilled off under vacuum to give pure (4-isocyanato-phenoxy)-acetic acid 2-{2-[2-(4-isocyanato-phenoxy)-acetoxy]-ethoxy}-ethyl ester (4.5 g) as a light yellow syrup. The product was characterized by 1H NMR (CDCl3) δ 3.65 (t, 2H, CH2), 4.35 (t, 2H, CH2), 4.65 (s, 2H, CH2), 6.75 (d, 2H, Ar), 7.00 (d, 2H, Ar).

Provenance & Evidence