35998-96-0

67-56-1

13280-60-9

35998-96-0

5-Amino-2-nitrobenzoic acid (Compound A) (910 mg) was dissolved in methanol (50 mL). Thionyl chloride (0.74 mL) was added slowly and dropwise to the above solution under cooling in an ice bath. Subsequently, the reaction mixture was heated to reflux for 12 hours. Upon completion of the reaction, the reaction solution was cooled to room temperature and concentrated under reduced pressure. The residue was purified by column chromatography using a chloroform-methanol solvent mixture as eluent to finally obtain methyl 5-amino-2-nitrobenzoate (410 mg, 42% yield).