Synthesis And Optimization Of L-Fucose And Its Derivatives

L-Fucose-containing glycans play important roles in selectin mediated leukocyte-endothelial adhesion, blood transfusion reactions, host-microbe interactions and numerous ontogenic events. The synthesis of L-fucose is crucial to its biological study. There are mainly three ways to synthesize L-fucose:enzyme and microorganism auxiliary method, production of fucose from the natural sources, the chemical synthesis of L-fucose.L-fucosylated glycoconjugates synthesis is relatively time consuming, tedious and a longer route, which restricts the biomedical study of fucose. L-galactose is one of the suitable raw materials to prepare L-fucose, which is very few in nature, still need chemical synthesis. In this paper, the synthesis of L-galactose was optimized, using D-galactose as starting material. In the synthesis of1,2,3,4-di-O-isopropylidene-6-O-benzyl-D-galactose, the reaction solvent benzene was replaced by N, N-dimethyl formamide, without tetrabutyl ammonium sulfate as catalyst, the yield can also reach94%. In the synthesis of6-O-benzyl-D-galactose,80%trifluoroacetic acid was replace by70%acetic acid, the yield increased by30%. In the synthesis of1,2,3,4,5-Penta-O-acetyl-D-galactose, the replacement of Catalyst platinum oxide by10%Pd/C increased the yield from59%to95%. In the synthesis of2,3,4,5,6-Penta-O-acetyl-aldehyde group-D-galactose, the replacement of the solution of15wt%Dess-Martin periodinane in methylene chloride by Dess-Martin periodinane solid, significantly reduced the cost and the yield was also acceptable. Using4-Methoxybenzene-sulfonyle to activate the sixth primary hydroxyl on L-galactose, followd by replacment with azide group, and the deprotection of1,2,3,4-isopropylidene and acetylation, the6-azide-1,2,3,4,5,6-Penta-O-acetyl-L-fucose synthesized successfully.The further study of the work is the metabolic incorporation the fucosyl direvatives to live cell then linked to alkynly functionalized magnetic nanoparticles, and the application to separate and enrich fucoslyated glyprotins.