between the chemical structure and cytotoxic activity of betulinic acid (1) derivatives were investigated. Eight lupanederivatives (1-8), one of them new (6), five diosphenols (9-13), four of them new (10-13), two new norderivatives (14 and 15), five seco derivatives (16-20), four of them new (16, 17, 19, and 20), and three new seco-anhydrides (21-23) were synthesized from 1, and their activities were
The aim of this work was to find an optimal ester group for preparation of lupane derivatives connecting high cytotoxicity with good chemical and pharmacological properties. Activities of methyl-, pivaloyloxymethyl-(Pom-), and acetoxymethyl(Acm-) esters were compared with the activity of free acids. Although the methyl- and Pom-esters were generally less active than free acids, some Acm-esters had cytotoxicity similar to or even better than the starting compounds. Cytotoxic activity was measured in five cancer cell lines. (c) 2005 Elsevier Ltd. All rights reserved.