Synthesis and properties of unsaturated halogeno-ketonucleosides. A new route to vinyl- and epimino-nucleosides

Abstract

The first synthesis of unsaturated halogeno-ketonucleosides has been accomplished by oxidation of 3′,4′-anhydrohexosylpurines followed by the action of lithium halide on the keto-anhydro-intermediate. Nucleophilic additions to these new compounds were especially studied. Sodium borohydride was shown to add to the carbonyl group providing a new and simple route to unsaturated nucleosides. Hydrazoic acid added to the double bond by a 1,2-addition mechanism, leading to a triazolo-nucleoside. 1,4-Addition of cyclohexylamine followed by intra molecular elimination of bromine afforded an epimino-nucleoside, which constituted the first example of an aziridine derivative in the nucleoside field. The structure of the new compounds obtained was ascertained from a study of their ¹H and ¹³C n.m.r. spectra.