Ⅰ. Studies On Efficiently Stereoselective Synthesis Of Mannosides And Related Oligosaccharides Ⅱ. Synthetic Studies On Phenylpropanoid Glycosides

In the last ten year, various physiological activies of glycosyl residues in glycoproteins,glycolipids, glycophospholipids and other glycoconjugates have been recognized gradually, and these biological functions have stimulated organic chemists to be engaged in the synthesis of glycosides and oligosaccharides, and its methodological research with great interest.Major advances in the synthesis of oligosaccharides have been made by the use of the Koenigs-Knorr method, trichloroacetimidate and thioglycoside method. The disadvantage of this procedure have led to an intensive search for new methods. Our major object is to solve some problems on the synthesis of mannosides and oligosaccharides, and to increase the yields of products and improve the synthetic stereoselectivity.Mannosides and related oligosaccharides widely distribute in various species of plants, and possess important pharmacological activities. So far, there were no efficient methods for the syntheisis of mannosides due to the characteristic structure of mannopyranose. Now, we reported here the stereoselective synthesis of some mannosides and related oligosaccharides in assistance with the considerable experience of glycoside synthesis in our department.1. The efficiently stereoselective synthesis of some mannosides and its oligosaccharides by anomeric activation method.We found that different leaving groups, e·g. trichloroacetoxy, trimethylsiloxy and 3.5-dinitrobenzoyloxy in the benzylated mannopyranoside produced different yields while they reacted with a series of...