A3 Adenosine Receptor Antagonists

During the past years a number of potent and selective antagonists for the human A3 adenosine receptor (AR) have been developed, including tricyclic compounds, such as triazoloquinazoline, pyrazolo-triazolopyridine, imidazopurinone, triazoloquinoxaline and pyrazoloquinoline derivatives. Bicyclic compounds include isoquinoline and related quinazoline derivatives. Monocyclic dihydropyridine and pyridine derivatives also proved to be potent selective A3 AR antagonists. So far, no potent, selective antagonist is available for rodent A3 ARs. Most of the A3 AR antagonists are highly lipophilic and exhibit very poor water-solubility. Potential therapeutic applications for A3 AR antagonists include inflammatory diseases, asthma, stroke, and glaucoma.