Efficient synthesis of coumarin based triazole linked O-glycoconjugates as new bio-active glycohybrids.

Glycohybrids are biologically significant molecules with variety of biological functions and are found as structural motifs in numerous natural products. Here, we report the synthesis of various new coumarin-based O-glycoconjugates as glycohybrids that are chirally enriched and bridged by 1,2,3-triazoles ring system. The1,2,3-triazoles bridging was done via CuAAC click-chemistry. Click chemistry offers several advantages, including high chemo- and regioselectivity, mild reaction conditions, easy purification, and compatibility with multiple functional groups. Two series of O-glycoconjugates as new glycohybrids were designed and efficiently synthesized in very good isolated yields, using d-glucose, d-galactose, d-mannose, d-arabinose, 3,4,6-tri-O-acetyl-D-glucal, 3,4,6-tri-O-acetyl-D-galactal and 3,4-di-O-acetyl-D-arabinal derived 1-O-propargylated glycosides, reacting with various 4-azidocoumarins under click-chemistry reaction conditions. The prepared new coumarin-based O-glycoconjugates as glycohybrids were found to possess anticancer activity against MCF-7 breast cancer cell lines at micromolar concentration.