Synthesis and biological activities of 5′-ethylenic and acetylenic modified l-nucleosides and isonucleosides

Two series of 6′-halovinyl-adenosine stereoisomers including 5′-ethylenic and acetylenic substituted l-adenosine, 5′-ethylenic and acetylenic substituted isonucleosides were synthesized. In the l-nucleoside series, compounds , , and showed modest inhibition of SAH hydrolase (21, 44, 50 and 26% respectively) at 100 μM. The l-isomers of 5′-ethylenic and acetylenic modified isonucleoside , exhibited no activity for the inhibition of SAH hydrolase, however, the d-isomers and showed some activities in the same test (35 and 21%). It indicated clearly the strict stereochemical requirement for the substrate of SAH hydrolase. Compounds , , , exhibited modest to good inhibition effects on the growth of HeLa cells or Bel-7420 cells at 1 μM (64, 44, 53 and 82% respectively).