Synthesis of triazolylmethyl-linked nucleoside analogs via combination of azidofuranoses with propargylated nucleobases and study on their cytotoxicity

Copper(I)-catalyzed azide–alkyne 1,3-dipolar cycloaddition reactions (CuAAC) between azidofuranoses and propargyl-nucleobases were carried out in the presence of CuSO4·5H2O and sodium ascorbate as catalytic system to provide the corresponding 1,4-disubstituted-1,2,3-triazole-bridged nucleoside analogs in good yields. Twelve new sugar-based triazolylmethyl-linked nucleoside analogs were synthesized and screened for their cytotoxic activity against MDA-MB-231, Hep3B, PC-3, SH-SY5Y, and HCT-116 cancer cell lines and control cell line (L929). Most of the compounds were moderately effective against all the cancer cell lines assayed. Particularly, among the tested compounds, 1,2,3-triazole-linked 5-fluorouracil–mannofuranose hybrid was found to be the most potent cytotoxic agent against HCT-116, Hep3B, SH-SY5Y cells with IC50 values of 35.6, 71.1, and 75.6 μM, respectively. None of the triazolylmethyl-linked nucleoside analogs exhibited cytotoxic effect against the control cells L929.