117253-15-3Relevant academic research and scientific papers
Synthesis of building blocks for an iterative approach towards oligomers of the Streptococcus pneumoniae type 1 zwitterionic capsular polysaccharide repeating unit
Ní Cheallaigh, Aisling,Oscarson, Stefan
, p. 940 - 960 (2016)
Zwitterionic capsular polysaccharide extracts, 8 kDa in mass, from Streptococcus pneumoniae type 1 (Spt1) have shown unique T-cell activating properties. Oligomers of the trisaccharide repeating unit of the Spt1 capsular polysaccharide [3)-4-NH2-α-d-QuipNAc-(14)-α-d-GalpA-(13)-α-d-GalpA-(1-]n of defined length are needed to further investigate this response. An approach towards iteratively extendable trisaccharide building blocks of the zwitterionic capsular polysaccharides of Spt1 is described. Key elements include the comparison of pre-glycosylation oxidation and post-glycosylation oxidation approaches using thioglycoside donors to the target trisaccharide, the optimisation of the post-glycosylation oxidation approach, and the conversion of the trisaccharide to building blocks tailored for iterative glycosylation. The construction and evaluation of stereotunable 2-N-3-O-oxazolidinone donors for the common bacterial 2-acetamido-4-amino-2,4,6-trideoxy-α-d-galactopyranoside motif is also described, as is a key intermediate for their efficient synthesis.
2-(Trimethylsilyl)ethyl Glycosides. Synthesis, Anomeric Deblocking, and Transformation into 1,2-Trans 1-O-Acyl Sugars
Jansson, Karl,Ahlfors, Stefan,Frejd, Torbjoern,Kihlberg, Jan,Magnusson, Goeran,et al.
, p. 5629 - 5647 (2007/10/02)
Twenty-seven mono --> tetrasaccharidic 2-(trimethylsilyl)ethyl (TMSET) glycosides were synthesized by the Koenigs-Knorr-type method in combination with a wide range of standard reagents for glycoside synthesis and protecting-group chemistry.Variously protected TMSET glycosides were treated with BF3*Et2O (0.7-0.8 equiv) and different carboxylic anhydrides (1.1-15 equiv) in toluene at 22-55 deg C, which gave in one step the corresponding protected 1-O-acyl sugars.In the majority of cases, the yields of purified compounds exceeded 90percent and the anomeric configuration of the starting TMSET glyoside was conserved to a large extent (>95percent) in most of the 1-O-acylated products.Unprotected and acetyl-, benzoyl-, benzyl-, dimethyl-tert-butylsilyl-, and phthaloyl-protected mono-->tetrasaccharidic TMSET glycosides were anomerically deblocked by using trifluoroacetic acid in dichloromethane at 0-22 deg C for 10-30 min.The hemiacetal products were isolated in 88-96percent yield; all reagents and byproducts were volatile and easily removed.
