1,4-Dioxane → HCID 117716233, compound

Participants

Reaction Conditions

Reaction Steps

6-(4-Aminophenoxy)-hexanoic acid 2-{2-[6-(4-aminophenoxy)-hexanoyloxy]-ethoxy}-ethyl ester (5 g) was dissolved in dry 1,4-dioxane (80 ml) under nitrogen atmosphere. The solution was cooled to below 10° C. A solution of triphosgene (4.8 g) in dry 1,4-dioxane (20 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 (25 ml) was added. The solvents were distilled off under vacuum. The residue was re-evaporated from dry 1,4-dioxane (50 ml) and dry toluene (30 ml) and charcoal (2 gram) was added. The solution was filtered hot. The toluene was distilled off under vacuum to give pure 6-(4-isocyanatophenoxy)-hexanoic acid 2-{2-[6-(4-isocyanatophenoxy)-hexanoyloxy]-ethoxy}-ethyl ester (4.5 g) as a light yellow oil. The product was characterized by 1H NMR (CDCl3) δ 1.48 (m, 2H, CH2), 1.68 (m, 2H, CH2), 1.78 (m, 2H, CH2), 2.37 (t, 2H, CH2), 3.68 (t, 2H, CH2), 3.92 (t, 2H, CH2), 4.24 (t, 2H, CH2), 6.78 (d, 2H, Ar), 6.97 (d, 2H, Ar).

Provenance & Evidence