Methods for the synthesis of xanthine-derived polycyclic fused systems

Abstract

Xanthines are a widely known group of alkaloids, commonly used as bronchodilators and psycho and cardiac stimulants. Most of their actions are principally connected with either antagonism of adenosine receptors or phosphodiesterase inhibition; nevertheless, other profiles of their biological activity - antiviral, antitumor or anticancer - are also known. Here, we present a review of the main synthetic methods to obtain xanthine-derived heterocyclic fused systems. The five-, six- or seven-membered heterocyclic ring is attached to the purine-2,6-dione core with one or two bridgehead (ring junction) nitrogen atoms. The biological activity profile of the individual heterocyclic systems is mentioned.