3-Amino-4-chlorobenzoic acid

40872-87-5

2840-28-0

General procedure for the synthesis of 3-amino-4-chlorobenzoic acid from methyl 3-amino-4-chlorobenzoate: to a stirred solution of methyl 3-amino-4-chlorobenzoate (0.300 g, 1.62 mmol) in tetrahydrofuran (20 mL) was added a solution of lithium hydroxide (0.340 g, 8.10 mmol) in water (5 mL). The reaction mixture was stirred at room temperature for 12 hours (the reaction progress was monitored by silica gel thin layer chromatography with ethyl acetate-hexane as the unfolding agent, 1:1, v/v). After completion of the reaction, the solvent was removed by distillation under reduced pressure. The resulting lithium salt was acidified with 1% (w/v) citric acid solution at 0 °C and extracted with ethyl acetate (2 × 20 mL). The organic phases were combined, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give 3-amino-4-chlorobenzoic acid as a white solid (yield 0.200 g, 72.01%).