The general procedure for the synthesis of 4-oxo-4-(((3R,5aS,6R,8aS,9R,10R,12R,12aR)-3,6,9-trimethyldecahydro-3H-3,12-epoxy[1,2]dioxysipin [4,3-i]isochromene-10-yl)oxy)butanoic acid from succinic anhydride and artemisinin was as follows: artemisinin (500 mg) was mixed with cationic exchange resin (1 g) in tetrahydrofuran (10 mL) for 5 min at room temperature. Subsequently, sodium borohydride (250 mg) was slowly added over 10 min and the reaction mixture was continued to be stirred at 20-35°C for 30 min. Upon completion of the reaction, succinic anhydride (250 mg) and triethylamine (0.7 mL) were added sequentially at room temperature and the reaction mixture was stirred for another 1 hour at the same temperature. At the end of the reaction, the resin was removed by filtration. The crude product (710 mg) was purified by conventional post-treatment and column chromatography to afford 480 mg of pure 4-oxo-4-(((3R,5aS,6R,8aS,9R,10R,12R,12aR)-3,6,9-trimethyldecahydro-3H-3,12-epoxy[1,2]dioxysipin[4,3-i]isochromene-10-yl)oxy)butanoic acid in a yield of 96% (w/w).