Preparation and antibacterial activity of di-, tri- and tetraoic acids derived from 3,4-secolupane

Diacids XXIII and XXIV, triacid XXVII and tetraacid XVI were prepared from 3,4-secodiacid V and from nitrile XVII by modifying the isopropenyl groups in position 5 and 19. Procedures for selective esterification of the acids and the hydrolysis of their esters in position 3, 23 and 28 were elaborated and the methyl esters VII, XI, XII, XXVI, XXVIII, XXX and XXXI prepared. The structures of the derivatives prepared were confirmed by mass spectra. The antibacterial activity of the series of 3,4-secoacids derived from lupane and 19β,28-epoxy-18α-oleanane was also determined.