Prespacer glycosides in glycoconjugate chemistry. Dibromoisobutyl (DIB) glycosides for the synthesis of neoglycolipids, neoglycoproteins, neoglycoparticles, and soluble glycosides

3-Bromo-2-(bromomethyl) propyl (dibromoisobutyl or DIB) mono- to tetrasaccharide glycosides were prepared in moderate to high yields by treatment of the corresponding 1-O-acetyl saccharides with 3-bromo-2-(bromomethyl) propanol (DIBOL) and boron trifluoride etherate. Treatment of the DIB glycosides with alkyl- and ω-methoxycarbonylalkyl thiols gave the corresponding bis-sulfide glycolipids and spacer arm sugars, respectively. Oxidation of the sulfides with m-chloroperbenzoic acid gave the corresponding bis-sulfones. Treatment of the DIB glycosides with tetrabutylammonium fluoride gave the corresponding allylic bromide glycosides, and addition of thiols gave the allylic sulfides. Spacer arm and allylic bromide glycosides were coupled to bovine serum albumin and derivatized silica gel, thereby providing artificial glycoproteins and glycoparticles