Benzaldehyde was condensed with acetone to obtain ketone with * * * yoke, and then Michael added diethyl malonate to form a ring.

Firstly, benzaldehyde and acetone were condensed, and then sodium hydroxide solution was added dropwise under vigorous stirring, and the solution turned yellow immediately and the temperature rose rapidly. In order to prevent dibenzylidene acetone, ice bath should be carried out immediately. Immediately stabilize, remove the ice bath and stir at room temperature for 40 minutes. Acidification, brine washing, liquid separation and drying. The organic phase seems tasteless. After drying, sodium sulfate and molecular sieve directly enter the next step. Anhydrous ethanol reacts with sodium metal, then diethyl malonate is added and refluxed to form enolate. Adding the product of the previous step, continuing to heat the reaction, and stopping the reaction after 2 hours. After the ceasefire, 25%NaOH solution was added for decarboxylation. Heat and reflux for 3 hours. Then adding hydrochloric acid for acidification, cooling, crystallizing, filtering to obtain orange solid, and recrystallizing with anhydrous ethanol.