4093-31-6

4093-29-2

4093-31-6

General procedure for the synthesis of methyl 4-acetamido-5-chloro-2-methoxybenzoate from methyl 4-acetamido-2-methoxybenzoate: 136g of N,N-dimethylformamide (DMF) was added as solvent in a 1L reaction flask, followed by the addition of 50g of methyl 4-acetamido-2-methoxybenzoate, and stirred until it was completely dissolved. To the solution was added 50 g of N-chlorosuccinimide (NCS), which was slowly heated to 40 °C and the reaction was maintained at this temperature for 5 hours. The reaction temperature was then raised to 65 °C and the reaction continued for 4 hours. Upon completion of the reaction, the reaction mixture was cooled to 0 °C and thermo-crystallization was carried out for 8 h. The crude product of methyl 4-acetamido-5-chloro-2-methoxybenzoate was obtained, while the mother liquor of N,N-dimethylformamide was recovered. The crude product was dissolved in 100 g of deionized water, heated to 50 °C and kept for 4 hours, then cooled to 5 °C for filtration. The filtered solid was dried to obtain a white crystalline product, methyl 4-acetamido-5-chloro-2-methoxybenzoate 52.1 g, with a molar yield of 90.3% and HPLC purity ≥99.8%.