The cordycepin analogue of 2,5A and its threo isomer. Chemical synthesis, conformation and biological activity.

: A new synthesis of the cordycepin analogue of 2,5A and its threo isomer is reported along with an assessment of their conformations by circular dichroism spectroscopy. Evidence is also presented showing that these compounds are stable against 2,5A-specific phosphodiesterase and are not able to activate the 2,5A-dependent endoribonuclease, possibly due to a reduced binding to the latter enzyme as compared to that of 2,5A.