Synthesis and anti-influenza activity of a series of triterpene furoyloxy-acylates.

A series of lupane, oleanane and ursane furoyloxy-triterpenoids were synthesised via acylation with 2-furoyl chloride and subsequently tested for anti-influenza activity against the pandemic influenza virus A/Puerto Rico/8/1934 (H1N1). Among them, 3β-furoyloxy-oleanolic and 3β-furoyloxy-ursolic acids were the most potent with IC50 values 17 and 1 µM with selectivity indexes of 32 and 26, respectively. The molecular structure of compound 11 was determined by X-ray diffraction analysis.