Synthesis
31g of m-fluorobenzaldehyde, 3.3g of pyridine was added to a four-necked flask, heated to 90 C with stirring, stirring in 5 batches to add 31.25g of malonic acid until it was completely dissolved, and after the addition of malonic acid, the temperature was raised to 110 C with stirring and refluxing for 90 min. 75mL of 10% hydrochloric acid was added to the four-necked flask, and the flask was cooled down to room temperature. Filter, wash the solid with hot water above 70 , until the pH of the wash solution was neutral and the wash solution was colorless. The solid was dried to obtain white flaky crystals with a yield of 79.5%.
