Synthesis of glycoconjugate mimics by 'click chemistry'

Stereo-defined 2-deoxy propargyl glycosides can be used for the synthesis of corresponding 1,4-disubstituted sugar derived triazoles by using only CuI and stereo-defined sugar azide derivatives. The click chemistry which involves copper (I) catalysed alkyne-azide 1,3-dipolar cycloaddition, was used to prepare a library of glycoconjugates mimics. Different sugar propargyl-2-deoxy-O-α-d-glycopyranoside derivatives and β-glycopyranosyl azide derivatives were coupled using catalyst CuI to yield triazole glycoconjugates. The catalyst CuI (2.5 eq.) in CH₃CN was found to be most efficient for the synthesis of 1,4-disubstituted triazole scaffolds affording up to 94% of optimized yield and with retention of the anomeric configuration of the starting glycosides. The key feature of this methodology is the absence of sodium l-ascorbate/ascorbic acid which is most active substrate of current research with strong potential for click reactions. In this article, the library of novel stereoselective deoxy sugar derived triazole glycoconjugates have been synthesized and structures were determined by the ¹H, ¹³C & 2D NMR spectroscopy.