Synthesis of Potentially Biologically Active 6-(1,3-Butadiynyl) purines

摘要

1,3-Alkadiynyl(trimethyl)silanes were prepared by the Negishi or Sonogashira reactions of bromoethynyl(trimethyl)silane with several terminal alkynes in 34-75% yield. However, the direct Hiyama coupling of these compounds with 6-iodopurine derivatives has not been successful. Therefore, a modified Sonogashira reaction using TBAF or CsF for in situ removal of the trimethylsilyl group has been utilized. This methodology afforded the desired 6-(1,3-butadiynyl)purines in 47-87% yield.