New developments in A1 and A2 adenosine receptor antagonists
The aim of this article is to briefly present progress in the development of the potent adenosine receptor (AR) antagonists with high selectivity for either A1, A2A, or A2B ARs. The structural requirements for each AR subtype were discussed as well as their potential therapeutic use. In the search for new AR antagonists, series of imidazo-, pyrimido-, and diazepino-purindione derivatives as well as oxazolo-, oxazino-, and oxazepino-purindiones were designed, synthesized, and preliminarily evaluated in pharmacological studies. Oxygen-containing tricyclic derivatives were shown to be moderately potent AR antagonists exhibiting selectivity either for A1 or A2A ARs. Tricyclic purindiones with nitrogen in the third ring were generally more A2A AR selective. The compounds tested in vivo according to the Antiepileptic Drug Development Program of the National Institutes of Health (USA) were generally active as anticonvulsants in chemically induced seizures.