Synthesis of triazolyl-linked polysialic acids

A new approach for the synthesis of triazolyl-linked alpha-(2-9) oligosialic acids by iterative copper(I)-catalyzed allcyne azide cycloaddition (CuAAC) and desilylation has been developed. By using propargyl alpha-sialoside 5 and trimethylsilylated-propargyl 9-azido-alpha-sialoside 3 as building blocks, triazolyl-linked alpha-(2-9) di- to octa-sialic acids were constructed in good to moderate yields. Finally, the pseudo-alpha-(2-9)-oligosialic acids were obtained very smoothly via O-deprotection. The oligosialic acids with a triazolyl-linkage represent a new type of pseudooligosialic acids. This protocol may find applications in the preparation of oligosialic acid analogues with biological importance. (C) 2014 Elsevier Ltd. All rights reserved.Chemistry, OrganicSCI(E)0ARTICLExinshan@bjmu.edu.cn499405-94127