1242060-76-9Relevant academic research and scientific papers
A highly α-selective glycosylation for the convenient synthesis of repeating α-(1→4)-linked N-acetyl-galactosamine units
Yang, Lin,Ye, Xin-Shan
experimental part, p. 1713 - 1721 (2010/10/19)
The repeating GalpNAc-α-(1→4)-GalpNAc unit is part of a series of essential structures that can be found in many important biomolecules such as the glycoproteins and the O-antigenic polysaccharides of clinically important bacterial strains. In this paper, we describe an exclusive α-selective glycosylation reaction, using a 4,6-di-O-tert-butyldimethylsilyl-N- acetyloxazolidinone-protected thioglycoside as the glycosyl donor, under pre-activation conditions, with only half amount of the promoter, providing the product GalpNAc-α-(1→4)-GalpNAc in high isolated yield. This reaction can be also applied to increasing the length of the repeating structure, which is of significant use in further synthesis of branched or linear oligosaccharides.
Additive-controlled stereoselective glycosylations of oxazolidinone- protected glucosamine and galactosamine thioglycoside donors based on preactivation protocol
Geng, Yiqun,Ye, Xin-Shan
supporting information; experimental part, p. 2506 - 2512 (2010/12/25)
Based on a pre-activation protocol, the stereoselectivity of oxazolidinone-protected amino sugar thioglycoside donors towards glycosylations can be controlled by additives. Either - or -selectivity could be obtained by changing additives. 2,4,6-Tri-tert-butylpyrimidine (TTBP) was the best -directing additive, while thiophene worked as the best -directing additive. The bifunctional additives such as tetrabutyl ammonium iodide (TBAI) afforded either - or -selectivity depending on the amount added. Poor -selectivity of some glycosylations without any additives was greatly improved by adding TBAI or thiophene. Georg Thieme Verlag Stuttgart New York.
