Ethyl 2-aminobenzoate → 2-[(Ethoxycarbonyl)amino]benzoic acid ethyl ester

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Reaktionsschritte

To an ice cooled solution of ethyl-o-aminobenzoate 1 (33 g, 0.2 mole) in acetone (270 ml) was added with stirring an ice cooled solution of potassium carbonate (36.7 g, 0.27 mole) in water (214 ml) followed by addition of ethyl chloroformate (43 g, 0.4 mole). Stirring was continued at 0° C. for 11/2 hour and at 25° C. for 2 hours. The mixture was poured in water (300 ml) and extracted with three 300 ml portions of ether. The combined and dried (MgSO4) ether phases were evaporated in vacuo to give pure 2 (46.7 g, 98%). The product was recrystallized (EtOH, H2O) to give colorless crystals, mp <40° C. (Calc. for C12H15NO4 : C 60.75; H 6.37; N 5.90). (Found C 60.75; H 6.29; N 5.85) 1H NMR (CDCl3) δ= 1.3 (3H, t, J=7 Hz) 1.4 (3H, t, J=7 Hz) 4.2 (2H, q, J=7 Hz) 4.3 (2H, q, J=7 Hz) 6.9-8.5 (4H, AA'BB'). IR (CCl4): 3300(m), 2980(m), 1735(s), 1690(s), 1600(s), 1510(w), 1450(s).

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