Synthesis of 3'-fluoro analogue of Cl-IB-MECA as adenosine A3 receptor ligand.

Abstract

3'-Fluoro analogue 1 of selective and potent adenosine A3 receptor agonist, Cl-IB-MECA was synthesized from D-xylose via highly regioselective opening of lyxo-epoxide 4 with fluoride anion. Compared to the high binding affinity of Cl-IB-MECA to the A3 adenosine receptor, the corresponding 3'-fluoro derivative showed remarkably decreased binding affinity, indicating that 3'-hydroxyl group acts as hydrogen bonding donor, not hydrogen bonding acceptor like fluorine atom in binding to the A3 adenosine receptor.