Synthesis and Anti-Fungal Activity of Seven Oleanolic Acid Glycosides

In order to develop potential anti-fungal agents, seven glycoconjugates composed of alpha-L-rhamnose, 6-deoxy-alpha-L-talose, beta-D-galactose, alpha-D-mannose, beta-D-xylose-(1 -> 4)-6-deoxy-alpha-L-talose, beta-D-galactose-(1 -> 4)-alpha-L-rhamnose, beta-D-galactose-(1 -> 3)-beta-D-xylose-(1 -> 4)-6-deoxy-alpha-L-talose as the glycone and oleanolic acid as the aglycone were synthesized in an efficient and practical way using glycosyl trichloroacetimidates as donors. The structures of the new compounds were confirmed by MS, H-1-NMR and C-13-NMR. Preliminary studies based on means of mycelium growth rate, indicated that all the compounds possess certain fungicidal activity against Sclerotinia sclerotiorum (Lib.) de Bary, Rhizoctonia solani Kuhn, Botrytis cinerea Pers and Phytophthora parasitica Dast.