6-AMINOHEXYL GLYCOPYRANOSIDES AS LIGANDS FOR THE PREPARATION OF AFFINITY ADSORBENTS FOR THE PURIFICATION OF CARBOHYDRATE-BINDING PROTEINS

Syntheses are described of 6-aminohexyl and 2-aminoethyl glycopyranosides of the monosaccharides commonly found in glycoproteins and glycolipids. The ligands have been coupled to agarose, and the adsorbents so formed have been used in the isolation of the lectin from wheat-germ extracts. Various procedures for the formation of glycopyranosides from 14C-labelled per-O-acetylglycosyl halides and 6-(trifluoroacetamido)hexanol have been examined. Silver carbonate with a trace of iodine is the best catalyst found thus far for glycosidation of simple sugars, and mercuric cyanide for that of 2-acetamido-2-deoxyaldoses. With other catalysts, higher proportions of ortho esters are obtained. The rearrangement of an ortho ester by p-toluenesulfonic acid gives the glycoside, a partially deacetylated glycoside, and a substantial proportion of the aglycon acetate. A simple procedure for isolation of the deacetylated glycosides by use of chromatography on Dowex-50 (pyridinium form) is described. © 1979.