Synthesis and Biological Assessment of New Nucleosides of Pyrido[2,3-d]pyrimidine Derivatives Bearing Ribose and 2-Deoxyribose Moieties

Abstract

Herein, it is unprecedentedly reported the synthesis of some new β-D-ribo and β-D-2-dexoyribofuranosyl nucleosides of pyrido[2,3-d]pyrimidines derivatives where the sugar moiety is linked to pyrido[2,3-d]pyrimidines via S or N glycosidic bond. Therefore, pyrido[2,3-d]pyrimidine derivatives 3 and 6 were utilized as scaffolds to be incorporated with ribose and 2-deoxyribose moieties. The glycosylation reactions were carried out under optimized conditions to enhance the regioselectivity and stereoselectivity during the glycosylation coupling. Various strategies have been applied to afford the desired N-nucleosides 16 and 19. Other approaches were utilized to afford the S-nucleosides 9, 13, 21, and 24. The structural elucidations of the novel nucleosides formed are reported and ascertained by using IR, 1H NMR, 13C NMR spectra and microanalysis. All the synthesized compounds were screened against a panel of microorganism strains for antibacterial and antifungal activities as well as antitumor evaluation.