Benzoyl chloride → Benzoic acid, 2-benzoylhydrazide

Into a 300 mL three-neck flask was put 10 g (73 mmol) of benzohydrazide, and 25 mL of N-methyl-2-pyrrolidone was added thereto, and the mixture was stirred. After that, a mixed solution of 10 mL of N-methyl-2-pyrrolidone and 10 mL (88 mmol) of benzoyl chloride was dripped into the mixture through a 50 mL dropping funnel. This mixture was stirred at 80° C. for 3 hours, and the contents of the flask were reacted. After the reaction, the reaction solution was added to about 500 mL of water and the mixture was stirred, so that a solid was precipitated. The precipitated solid was collected by suction filtration. The collected solid was washed with water, and methanol was added to the obtained solid so that the solid was washed to give 10 g of a powdery white solid of 1,2-dibenzoylhydrazine, which was the object of the synthesis, at a yield of 57%.