Recent progress in the syntheses of carbocyclic nucleosides

Abstract

Carbocyclic nucleosides are nucleoside analogues whose furanose rings are substituted by carbocycles. As analogues, many carbocyclic nucleosides show good antiviral or antitumor activities. Also, due to the absence of a typical glycosidic bond, carbocyclic nucleosides usually exhibit more metabolic stabilities to phosphorylases and hydrolases than natural nucleosides. Therefore, medicinal chemists have focused their attention on designing and preparing new carbocyclic nucleoside analogues, in efforts to discover new more powerful and safe antiviral agents. The syntheses of carbocyclic nucleosides in the past five years classified by different types of bases are reviewed in this article, denoted as purine carbocyclic nucleosides, pyrimidine carbocyclic nucleosides and carbocyclic analogues of C-nucleosides, with an emphasis on the synthesis of purine carbocyclic nucleosides. In the end, the problems and future trends of carbocyclic nucleoside research are discussed. It is still a challenge to intelligently design and efficiently synthesize the novel carbocyclic nucleosides targeted for some special purposes.