Synthesis and Characterization of New Isatin Nucleosides

Abstract

In this research, a series of new nucleoside analogues 25–36 of substituted isatin as nucleobase were synthesized in three steps. The reaction sequence is started from the condensation of free sugar (D-glucose and L-rhamnose) with different anilines to afford the N-arylglycosylamines 1–12 which subsequently O-acetylated in the presence of acetic anhydride/pyridine. The resulting acetylated N-arylglycosylamines 13–24 were then subjected to an intramolecular cyclization with oxalyl chloride in the presence of anhydrous aluminum chloride to yield the target isatin nucleosides. The synthesized compounds were characterized by the FTIR, 1H-NMR and13 C-NMR spectroscopy. The stereochemistry was established based on the coupling constants observed between vicinal hydrogens of the glycon that confirmed the β-configuration of the synthesized nucleosides with a 4C1 conformation of the glucosides and a 1C4 conformation of the rhamnosides.