Synthesis of [alpha]- and [beta]-glycosides containing spin labels, as probes for studies of carbohydrate-protein interaction

Abstract

Nitroxide spin-labeled [alpha]--glycopyranosides were synthesized in good yield and in a highly stereoselective manner by reaction of per-O-benzyl-[alpha]--glycopyranosyl bromides with 2,2,6,6-tetramethyl-4-piperidinol under the bromide ion-catalyzed conditions devised by Lemieux et al. After hydrogenolysis, the deblocked intermidiates were oxidized to give the desired, spin-labeled [alpha]--glycopyranosides. Nitroxide spin-labeled [alpha]--glycopyranosides, as well as a [beta]-maltoside, were synthesized by standard methods. The synthesis is also described of 2-amino-2-deoxy--glucose and --galactose derivatives having a spin label at C-2, and of the spin-labeled compound 1-[4-([beta]--galactopyranosyloxy)phenyl]-3-(2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl)-2-thiourea.