Abstract
Oxidative reactions of new oleanane triterpenoides. 19β,28-Epoxy-4,5-seco-3,5-cyclo-18α-olean-3(5)-ene (2) is an appropriate compound for oxidations, which lead to new oxidized compounds with potential biological activities. Several oxidations were used such as epoxidation, allylic oxidation, oxidative cleavage of double bond and other ones.
From the starting compound epoxides 3a, 3b and unsaturated ketone 4 were prepared. This ketone was further oxidized to diketone 6 and anhydride 7.
The double bonds of all unsaturated compounds were cleaved with ruthenium tetroxide to afford new A-seco oleananes. The structure and stereochemistry of the compounds were derived from IR, MS, (1)H and (13)C NMR spectra (1D and 2D COSY, TOCSY, NOESY, HSQC, HMBC).