First Total Synthesis of (±)-Elatadihydrochalcone and Its Derivatives

摘要

Pyranochalcones and pyranodihydrochalcones are an abundant subclass of the flavonoids and are widely found in nature. Members of the pyranochalcones and pyranodihydrochalcones have been associated with a wide variety of biological activities such as antimutagenic, antimicrobial, anti-ulcer, antitumor, anti-leishmania, and antimalarial activities. Furthermore, some plants are used as traditional medicines in China and Europe.Recently, naturally occurring elatadihydrochalcone bearing pyranodihydrochalcone moiety was isolated from seed-pods of Tephrosia elata, which was distributed in East Africa (Figure 1). This plant is also used as traditional medicine to treat infectious diseases. The crude extract from the seedpods of this plant showed anti-plasmodia activity with IC_(50) values of 2.8 ± 0.3 and 5.5 ± 0.3 μg/mL against chloro-quine-sensitive Sierra Leone I and chloroquine-resistant Indochina I strains, respectively. It is the first report on the occurrence of a p-hydroxydihydrochalcone in the genus Tephrosia species. The potent anti-plasmodia activity has stimulated interest in the synthesis of naturally occurring elatadihydrochalcone.