Diphosgene → Methyl 2-isocyanato-3-phenylpropanoate

Beteiligte Stoffe

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Reaktionsschritte

L-Phenylalanine methyl ester hydrochloride (6.00 g., 27.82 mmole) was slurried in anhydrous 1,4-dioxane (125 ml.), treated with trichloromethylchloroformate (5.05 ml., 41.86 mmole) and heated at 55° C. for 17.5 hours. The excess trichloromethylchloroformate and 1,4-dioxane were removed from the reaction mixture by distillation under slightly reduced pressure. The resultant residue was subjected to high vacuum distillation to afford the desired intermediate 2-isocyanato-3-phenylpropionic acid methyl ester (4.78 g., 84% yield). B.P. 83°-85° C. (100 μm Hg.) as a clear colorless liquid. 1H-NMR (200 MHz, CDCl3) δppm =3.12, dd, J=8.5 Hz., 2H (--CH2 --Ph), 3.83, s, 3H (--COOCH3), 4.28, m, 1H (--CH--CH2 --), 7.15-7.4, m, 5H (Ar--H).

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