Coumalic acid

617-48-1

500-05-0

The general procedure for the synthesis of coumaric acid from DL-malic acid was as follows: fuming sulfuric acid (287 g) was slowly added dropwise over a period of 2 hours to a suspension of DL-malic acid (200 g) dissolved in concentrated sulfuric acid (313 g) at 75 °C. After the dropwise addition was completed, the reaction mixture was continued to be stirred at the same temperature for 4 hours. Upon completion of the reaction, the mixture was cooled to room temperature and subsequently poured slowly into ice water over a period of 1 hour. After stirring for 15 minutes, the mixture was left to stand overnight. On the following day, the mixture was cooled to below 10°C and the coumaric acid crude product was isolated by filtration. After washing and drying, coumaric acid was obtained (71 g, 95% purity, 65% yield).