Design and Synthesis of Triazole-Linked xylo- Nucleoside Dimers.

Three triazole-linked nonionic xylo-nucleoside dimersTL-t-TxL,TL-t-ABzxLandTL-t-CBzxLhave been synthesized for the first time by Cu(I) catalyzed azide-alkyne [3 + 2] cycloaddition reaction (CuAAC) of 1-(3′-azido-3′-deoxy-2′-O,4′-C-methylene-β-D-ribo-furanosyl)thymine with different alkynes,i.e.,1-(5′-deoxy-5′-C-ethynyl-2′-O,4′-C-methylene-β-D-xylofuranosyl)thymine, 9-(5′-deoxy-5′-C-ethynyl-2′-O,4′-C-methylene-β-D-xylo-furanosyl)-N6-benzoyladenine and 1-(5′-deoxy-5′-C-ethynyl-2′-O,4′-C-methylene-β-D-xylofuranosyl)-N4-benzoylcytosine in 90%–92% yields. Among the two Cu(I) reagents, CuSO4.5H2O-sodium ascorbate in THF:tBuOH:H2O (1:1:1) and CuBr.SMe2in THF used for cycloaddition (click) reaction, the former one was found to be better yielding than the latter one. [ABSTRACT FROM PUBLISHER]