Penta-O-pivaloyl-galactopyranose and tetra-O-pivaloyl-galactopyranosyl bromide after electrophilic activation reacted with 6-O-protected 2-azido-galactosides to give the precursor structures of the Thomsen-Friedenreich antigen disaccharide with high regioselectivity, but low yield.With 4,6-Obenzylidene protected 2-azidogalactosides and 2-O-pivaloyl phenylthio galactosides, T-antigen disaccharides of this type were obtained in good yields. Glycosylation reactions of 4,6-O-benzylidene protected glucosamine derivatives with O-pivaloyl protected galactosyl bromide efficiently gave lactolactosamine disaccharides. Even a thioglycoside was efficiently galactosylated by this method resulting in the formation of a disaccharide thioglycoside useful itself as a potential glycosyl donor.
Penta-O-pivaloyl-galactopyranose和tetra-O-pivaloyl-galactopyranosyl溴在亲电活化后与6-O-保护的2-azido-galactosides反应,高选择性地形成Thomsen-Friedenreich抗原二糖的前体结构,但产率较低。使用4,6-Obenzylidene保护的2-azidogalactosides和2-O-pivaloyl苯硫基半乳苷,可以得到这种类型的T-抗原二糖,产率较高。4,6-O-benzylidene保护的葡萄糖氨基衍生物与O-pivaloyl保护的半乳苷溴的糖基化反应有效地产生了乳糖氨二糖。甚至通过这种方法,一种硫代糖苷也可以有效地被半乳苷化,形成一种作为潜在糖基供体的二糖硫代糖苷。