condensation of the carboxylic acid with bromo-glycosides was found to be more efficient in the synthesis of 28-glycosides. Two approaches were investigated and proved practicable in the preparation of 3,28- diglycosides. This method is suitable for preparing oleanolic acid glycosides with structural diversity for extensive biological evaluation and structure-activityrelationshipstudy, and it also apply new
In order to develop potential anti-fungal agents, seven glycoconjugates composed of a-L-rhamnose, 6-deoxy-a-L-talose, b-D-galactose, a-D-mannose, b-D-xylose-(1®4)-6-deoxy-a-L-talose, b-D-galactose-(1®4)-a-L-rhamnose, b-D-galactose-(1®3)-b-D-xylose-(1®4)-6-deoxy-a-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, 1H-NMR and 13C- 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.