TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Processes: D-aspartic acid methyl ester hydrochloride of formula (II) is prepared by suspending D-aspartic acid in methanol, cooling to - 5-0 degrees C, slowly adding thionyl chloride dropwise, heating to 25-35 degrees C, stirring and reacting for 4-5 hours, distilling under reduced pressure to remove methanol and obtain white solid, adding ethyl acetate, stirring and washing for 0.5 hour, filtering, and drying. Compound of formula (III) is prepared by dissolving compound of formula (II) in water, cooling to 0-5 degrees C, adding 40% aqueous methylamine solution dropwise, heating to 25-35 degrees C, stirring and reacting for 12-14 hours, concentrating under reduced pH, adjusting pH to 5 using 1 mol/L hydrochloric acid, adding acetone, stirring for 1 hour, filtering solid precipitate, and drying. Compound of formula (IV) is prepared by dissolving compound of formula (III) in methanol, adding triethylamine, adding ethyl fluoroacetate, adjusting temperature to 40-45 degrees C, adding ethyl trifluoroacetate dropwise, maintaining temperature at 40-45 degrees C, maintaining temperature at 30-35 degrees C for 14-16 hours, concentrating under reduced pressure, adding dichloromethane, and stirring and crystallizing at 0-5 degrees C in which molar ratio compound of formula (III):triethylamine:trifluoroacetate is 1:1.1:1.5-1.8. Active mixed anhydride of formula (V) is prepared by dissolving compound of formula (IV) in anhydrous tetrahydrofuran, adding diisopropyl ethylamine, adding CDI at 0-5 degrees C, and reacting at 30-40 degrees C for 4-6 hours in which volume of anhydrous tetrahydrofuran in ml is 4 times the weight of compound of formula (IV) in g. Crude sodium aspoxicillin is obtained by adding amoxicillin to acetonitrile solvent, adding triethylamine dropwise, stirring at 0-5 degrees C to dissolve and obtain supernatant, slowly adding supernatant to active mixed anhydride of formula (V), stirring and reacting for 6-7 hours, monitoring reaction using thin layer chromatography (TLC), adding methanol, slowly adding 10% sodium carbonate aqueous solution dropwise, stirring and reacting at 5-10 degrees C for 7-8 hours, adding acetone/methyl tert.-butyl ether solvent with volume ratio of 3:2, cooling to - 15 degrees C to - 10 degrees C, stirring and crystallizing for 3 hours, collecting precipitated solid, and filtering. Crude sodium aspoxicillin is purified by dissolving crude sodium aspoxicillin in 1200 ml purified water at 10-15 degrees C, adding activated carbon, stirring for 30-50 minutes, filtering, adding acetone to filtrate, cooling to - 10 degrees C to - 5 degrees C, and standing and crystallizing for 4-5 hours in which volume of water in ml is 8-9 times the weight of crude sodium aspoxicillin in g, and volume of acetone is 2-3 times the volume of water. Preferred Compositions: Molar ratio amoxicillin:compound of formula (IV) is 1:1.8-2, volume of methanol in ml is 1.5-2 times the weight of compound of formula (IV) in g, volume of 10% sodium carbonate aqueous solution in ml is 2.8-3.3 times the weight of compound of formula (IV) in g, and volume of acetone/methyl tert.-butyl ether mixed solvent in ml is 4 times the weight of compound of formula (IV) in g.