1375150-03-0

706792-04-3

General procedure for the synthesis of methyl 3-amino-5-ethoxybenzoate from methyl 3-ethoxy-5-nitrobenzoate: to methyl 3-ethoxy-5-nitrobenzoate (6.1 kg, 27.1 mol) prepared in step 2, methanol (54 L) and purified water (54 L) were added, followed by 10% palladium/carbon catalyst (6.1 kg, 10% wt/wt) . The reaction was carried out at room temperature with stirring in a hydrogen atmosphere at 4 atmospheres for 2.5 hours. Upon completion of the reaction, acetone (54 L) was added to dilute the reaction mixture, followed by removal of the 10% palladium/carbon catalyst by filtration. Methanol and acetone were removed by distillation under reduced pressure. The resulting solid was filtered and washed with pure water to give the final methyl 3-amino-5-ethoxybenzoate (4.88 kg, 92.2% yield, yellow solid). The product was characterized by 1H-NMR (400 MHz, CDCl3) with the following chemical shifts: δ 6.95 (s, 2H), 6.39 (s, 1H), 4.01 (q, J=6.8Hz, 2H), 3.87 (s, 3H), 3.76 (s, 2H), 1.38 (t, J=6.8Hz, 3H).