Discovery of FK453, a Novel Non-Xanthine Adenosine A1 Receptor Antagonist.

Abstract Novel 2-phenylpyrazolo[1,5-a]pyridine-3-acryloylamides were synthesized and evaluated for diuretic activities. FK453 (1d), the most potent compound in this series, was found to be a potent and selective adenosine A1 receptor antagonist, whereas 1e, the (S)-enantiomer of FK453, was a weak and non-selective adenosine antagonist.