Dual acting antioxidant A1 adenosine receptor agonists

Herein we report the synthesis and biological evaluation of some potent and selective A1 adenosine receptor agonists, which incorporate a functionalised linker attached to an antioxidant moiety. N6-(2,2,5,5-Tetramethylpyrrolidin-1-yloxyl-3-ylmethyl)adenosine (VCP28, 2e) proved to be an agonist with high affinity (Ki = 50 nM) and good selectivity (A3/A1 400) for the A1 adenosine receptor. N6-[4-[2-[1,1,3,3-Tetramethylisoindolin-2-yloxyl-5-amido]ethyl]phenyl]adenosine (VCP102, 5a) has higher binding affinity (Ki = 7 nM), but lower selectivity (A3/A1 = 3). All compounds bind weakly (Ki > 1 μM) to A2A and A2B receptors. The combination of A1 agonist activity and antioxidant activity has the potential to produce cardioprotective effects.