Synthesis of oleanolic disaccharide derivatives

Oleanolic acid 1 exists widely in food,medicinal herbs and other plants and possesses many attractive biological activities.Recently,some oleanolic derivatives were reported to have interesting anti-tumor activities.Herein,using association principle of drug design,OA disaccharide 17 was designed and synthesized by coupling α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl disaccharide moiety,which has proved to be a unique sugar sequence with strongly antitumor activity,and modified OA with a nitrile at C-17.