ethyl N-(4-aminophenyl)carbamate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: (4-Amino-phenyl)-carbamic acid ethyl ester (118 g, 0.65 mol) is dissolved in glacial acetic acid (2.0 L) under nitrogen and the mixture is heated to 90° C. Phthalic anhydride (102.0 g, 0.69 mol) is added portionwise over 30 minutes and the reaction is kept at 90° C. for 2 hours. The mixture is allowed to cool to ambient temperature and the precipitated solid is filtered off. The solid is washed on the filter with water (2 L) followed by diethylether (3 L) and then dried in vacuo. Yield 127 g (62%) title compound as white crystalline compound. LC/MS (m/z) 311.3 (MH+); tR=2.57 min. 1H NMR (DMSO-d6): 1.26 (t, 3H); 4.15 (q, 2H); 7.34 (dd, 2H); 7.58 (dd, 2H); 7.90 (ddd, 2H); 7.95 (ddd, 2H); 9.80 (s, 1H, NH). to cool to ambient temperature the precipitated solid is filtered off The solid is washed on the filter with water (2 L) dried in vacuo

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: (4-Amino-phenyl)-carbamic acid ethyl ester (118 g, 0.65 mol) is dissolved in glacial acetic acid (2.0 L) under nitrogen and the mixture is heated to 90° C. Phthalic anhydride (102.0 g, 0.69 mol) is added portionwise over 30 minutes and the reaction is kept at 90° C. for 2 hours. The mixture is allowed to cool to ambient temperature and the precipitated solid is filtered off. The solid is washed on the filter with water (2 L) followed by diethylether (3 L) and then dried in vacuo. Yield 127 g (62%) title compound as white crystalline compound. LC/MS (m/z) 311.3 (MH+); tR=2.57 min. 1H NMR (DMSO-d6): 1.26 (t, 3H); 4.15 (q, 2H); 7.34 (dd, 2H); 7.58 (dd, 2H); 7.90 (ddd, 2H); 7.95 (ddd, 2H); 9.80 (s, 1H, NH). to cool to ambient temperature the precipitated solid is filtered off The solid is washed on the filter with water (2 L) dried in vacuo

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 4-Nitro-aniline (100 g, 0.72 mol) is dissolved in ethyl acetate (800 mL) and diisopropylethylamine (89.6 mL, 0.936 mol) is added. Ethyl chloroformiate (252 mL, 1.45 mol) dissolved in ethyl acetate (200 mL) is added and the solution is stirred for 18 h at ambient temperature. The mixture is washed with 2M HCl (300 mL) and brine (300 mL), dried (MgSO4) and concentrated in vacuo to half of the original volume. To the resulting solution is added palladium on activated carbon (10 g, 5% Pd, 50% H2O) and the mixture is hydrogenated on a Parr apparatus (pH2=3 bar) at ambient temperature for 12 hours. The mixture is filtered through Celite and the solvent evaporated in vacuo to give 118 g (90%) of the title compound as crystalline product. is added The mixture is washed with 2M HCl (300 mL) and brine (300 mL) dried (MgSO4) concentrated in vacuo to half of the original volume To the resulting solution is added palladium on activated carbon (10 g, 5% Pd, 50% H2O) the mixture is hydrogenated on a Parr apparatus (pH2=3 bar) at ambient temperature for 12 hours The mixture is filtered through Celite the solvent evaporated in vacuo

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 4-Nitro-aniline (100 g, 0.72 mol) is dissolved in ethyl acetate (800 mL) and diisopropylethylamine (89.6 mL, 0.936 mol) is added. Ethyl chloroformiate (252 mL, 1.45 mol) dissolved in ethyl acetate (200 mL) is added and the solution is stirred for 18 h at ambient temperature. The mixture is washed with 2M HCl (300 mL) and brine (300 mL), dried (MgSO4) and concentrated in vacuo to half of the original volume. To the resulting solution is added palladium on activated carbon (10 g, 5% Pd, 50% H2O) and the mixture is hydrogenated on a Parr apparatus (pH2=3 bar) at ambient temperature for 12 hours. The mixture is filtered through Celite and the solvent evaporated in vacuo to give 118 g (90%) of the title compound as crystalline product. is added The mixture is washed with 2M HCl (300 mL) and brine (300 mL) dried (MgSO4) concentrated in vacuo to half of the original volume To the resulting solution is added palladium on activated carbon (10 g, 5% Pd, 50% H2O) the mixture is hydrogenated on a Parr apparatus (pH2=3 bar) at ambient temperature for 12 hours The mixture is filtered through Celite the solvent evaporated in vacuo

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 4-Nitro-aniline (100 g, 0.72 mol) is dissolved in ethyl acetate (800 mL) and diisopropylethylamine (89.6 mL, 0.936 mol) is added. Ethyl chloroformiate (252 mL, 1.45 mol) dissolved in ethyl acetate (200 mL) is added and the solution is stirred for 18 h at ambient temperature. The mixture is washed with 2M HCl (300 mL) and brine (300 mL), dried (MgSO4) and concentrated in vacuo to half of the original volume. To the resulting solution is added palladium on activated carbon (10 g, 5% Pd, 50% H2O) and the mixture is hydrogenated on a Parr apparatus (pH2=3 bar) at ambient temperature for 12 hours. The mixture is filtered through Celite and the solvent evaporated in vacuo to give 118 g (90%) of the title compound as crystalline product. is added The mixture is washed with 2M HCl (300 mL) and brine (300 mL) dried (MgSO4) concentrated in vacuo to half of the original volume To the resulting solution is added palladium on activated carbon (10 g, 5% Pd, 50% H2O) the mixture is hydrogenated on a Parr apparatus (pH2=3 bar) at ambient temperature for 12 hours The mixture is filtered through Celite the solvent evaporated in vacuo