Reaktion #641245

Reaktionsgleichung

(4-amino-phenoxycarbonylmethoxy)-acetic acid 4-amino-phenyl ester

1,4-dioxane

diphosgene

1,4-dioxane

→

(4-Isocyanato-phenoxycarbonylmethoxy)-acetic acid 4-isocyanato-phenyl ester

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.DISTILLATIONThe condenser was then arranged for distillation and solvent
2. 2
   Sonstigeremoved by distillation at atmospheric pressure until the volume of the reaction mixture
3. 3
   workup.ADDITIONFresh dry dioxane (10 ml) was added
4. 4
   workup.DISTILLATIONdistilled off the solvents under vacuum
5. 5
   SonstigeThe residue was re-evaporated two times from dry dioxane (2×10 ml)

Vorschrift

To a solution of (4-amino-phenoxycarbonylmethoxy)-acetic acid 4-amino-phenyl ester (27) (2 grams, 6.32 mmoles) in dry 1,4-dioxane (32 ml) under nitrogen atmosphere was cooled to 10° C. and added a solution of diphosgene (4 grams, 13.47 mmoles) in 1,4-dioxane (8 ml) in one lot and heated to a temperature of 100° C. for 2 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 (10 ml) was added and distilled off the solvents under vacuum. The residue was re-evaporated two times from dry dioxane (2×10 ml) to give crude 28 (4-Isocyanato-phenoxycarbonylmethoxy)-acetic acid 4-isocyanato-phenyl ester, which was recrystallized from toluene as a white powder with a melting point of 150.5-152.4° C., IR: 2316.1 cm−1, 2274.3 cm−1. The pure product 28 was also characterized using 1H NMR spectroscopy in CDCl3: δ 4.56 (s, 2H, CH2), 7.10 (s, 4H, Ar).

Quelle