An approach to alicyclic ring-fused xanthines

A convenient three-step approach to the synthesis of five to eight-membered alicyclic ring-fused xanthines was developed. The method included reaction of lactim or thiolactim ethers with 6-aminouracils, followed by bromination and copper-catalyzed arylation. The procedure allowed preparation of the title compounds in 21–36% overall yields.