Synthesis of labelled dihydroartemisinic acid

Abstract [15- 13 C 2 H 3 ]-Dihydroartemisinic acid ( 2a ), [15-C 2 H 3 ]-dihydroartemisinic acid ( 2b ) and [15- 13 CH 3 ]-dihydroartemisinic acid ( 2c ) have been obtained in good yield and high isotopic enrichment by a reconstructive synthesis from artemisinin. These labelled compounds were designed to be used in biosynthetic experiments to determine the origins of artemisinin and other sesquiterpene natural products from Artemisia annua .