3,4-(Methylenedioxy)phenylacetic acid

Step 1, Preparation of 3,4-methylenedioxyphenylethanolic acid

Measure 50 ml of piperine into a three-necked flask equipped with a thermometer. Slowly add 45-50 ml of concentrated sulfuric acid in an ice bath. Under strict temperature control of -6 to 0℃, slowly add 60-75 ml of 50% glyoxylic acid aqueous solution. React at this temperature for 7-9 h. After the reaction is complete, add 500-600 ml of water, stir at room temperature for 1-2 h, filter, dry, and obtain the product with a molar yield of 90-95%. Step 2: Preparation of 3,4-(METHYLENEDIOXY)PHENYLACETIC ACID 50g of 3,4-methylenedioxyphenylethanolic acid, 9-10g of sodium iodide, 26-28ml of phosphoric acid, and 1.9-2.0ml of methanesulfonic acid were placed in a three-necked flask and reacted at 90-95℃ for 5-6 hours. After the reaction was complete, 500-600ml of water was added to obtain a white solid. The product was obtained by filtration, with a yield of 90-93%.