Step 1: 4-nitrobenzoyl--alanine sodium salt
In a 500 ml three-necked flask, -alanine (5.7 g, 64.86 mmol) was added sequentially, and 20 g of sodium hydroxide + 200 g of purified water formulated in aqueous sodium hydroxide solution was stirred to dissolve. The reaction temperature was allowed to drop to 5 C, and then 4-nitrobenzoyl chloride (little and often, 10 g, 54.05 mmol) was added. The reaction was carried out at a reaction temperature of 5C for 3 h. An aqueous solution of the target product was obtained, which was directly cast to the next step without post-treatment.
Step 2: p-Aminobenzoyl-beta-alanine
In the 500 ml three-necked flask of the above reaction aqueous solution, Zr12-TPDC-Pd (0.5 g) was added, H2 was passed, and stirred, until no hydrogen was absorbed at room temperature and pressure. Then hydrochloric acid was slowly added to adjust PH = 1-2, and then stirred for 10 minutes to obtain p-aminobenzoyl-beta-alanine solution.
