New types of spin-labelled sugar and nucleoside analogs: Pyrrolidine, morpholine and piperidine N-Oxyls

Abstract

Analogs of blocked furanose ( 20) or pyranose sugars (i.e. 15) and of nucleosides (i.e. 23) in which the ring oxygen has been replaced with a -N(OH)-bridge have been prepared in generally good yields by a general reductive cyclization procedure preserving the configuration of the preexistant asymetric centers and proceedings stereoselectively (in more favorable cases stereospecifically) when creating a new asymetric center. The title compounds oxidized to nitroxide free radicals affording usable ESR spectra.