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Synthesis, Characterization and Intramolecular Cyclisation of 5-Substituted Acyclic Nucleosides

A. Nura-Lama, M. Bicaj, R. Hoti and A. Musaj

In this paper, synthesis of some new acyclic nucleosides and the intramolecular cyclisation reaction of suitably activated 5-(acetoxymethyl)-1-(2,3-dimethylsulfonyloxypropyl) uracil (4) is described. All compounds were characterised by 1H NMR, 13C NMR and elemental analyses. This intramolecular cyclisation reaction involved nucleophilic attack of the C-2 enoxide ion at the C-2′ rather then at the C-3′ position of the aliphatic chain. The preferred formation of the five-member 2, 2′-anhydro structure was evidenced by the isolation of bicyclical products, 2-methylsulfonyloxymethyl-2,3-dihydro-6- acetoxymethyl-7H-oxazolo [3,2-a]-pyrimidine-7-one (5).