Xanthine scaffold: available synthesis routes to deliver diversity by derivatization
The functionalization of the skeletal systems of heterocycles represents a significant goal
for the development of new compounds. The heterocyclic molecule xanthine (3,7-dihydro-1Hpurine-
2,6-dione) is a purine base with a bicyclic ring skeleton and four different nitrogen atoms,
three of them are -NH groups. The principal derivatives are the well known natural methylxanthines
(e.g., caffeine, theophylline and theobromine) that have prominent physiological effects at a very low