29485-85-6Relevant articles and documents
Synthesis of Altrose Poly-amido-saccharides with β-N-(1→2)- d -amide Linkages: A Right-Handed Helical Conformation Engineered in at the Monomer Level
Xiao, Ruiqing,Dane, Eric L.,Zeng, Jialiu,McKnight, Christopher J.,Grinstaff, Mark W.
, p. 14217 - 14223 (2017/10/17)
The design and synthesis of amide-linked saccharide oligomers and polymers, which are predisposed to fold into specific ordered secondary structures, is of significant interest. Herein, right-handed helical poly amido-saccharides (PASs) with β-N-(1→2)-d-amide linkages are synthesized by the anionic ring-opening polymerization of an altrose β-lactam monomer (alt-lactam). The right-handed helical conformation is engineered into the polymers by preinstalling the β configuration of the lactam ring in the monomer via the stereospecific [2+2] cycloaddition of trichloroacetyl isocyanate with a d-glycal possessing a 3-benzyloxy group oriented to the α-face of the pyranose. The tert-butylacetyl chloride initiated polymerization of the alt-lactam proceeds smoothly to afford stereoregular polymers with narrow dispersities. Birch reduction of the benzylated polymers gives water-soluble altrose PASs (alt-PASs) in high yields without degradation of the polymer backbone. Circular dichroism analysis shows the alt-PASs adopt a right-handed helical conformation in aqueous solutions. This secondary conformation is stable over a wide range of different conditions, such as pH (2.0 to 12.0), temperature (5 to 75 °C), ionic salts (2.0 M LiCl, NaCl, and KCl), as well as in the presence of protein denaturants (4.0 M urea and guanidinium chloride). Cytotoxicity studies reveal that the alt-PASs are nontoxic to HEK, HeLa, and NIH3T3 cells. The results showcase the ability to direct solution conformation of polymers through monomer design. This approach is especially well-suited and straightforward for PASs as the helical conformations formed result from constraints imposed by the relatively rigid and sterically bulky repeating units.
Fluorine-directed β-galactosylation: Chemical glycosylation development by molecular editing
Durantie, Estelle,Bucher, Christoph,Gilmour, Ryan
, p. 8208 - 8215 (2012/08/27)
Validation of the 2-fluoro substituent as an inert steering group to control chemical glycosylation is presented. A molecular editing study has revealed that the exceptional levels of diastereocontrol in glycosylation processes by using 2-fluoro-3,4,6-tri-O-benzyl glucopyranosyl trichloroacetimidate (TCA) scaffolds are a consequence of the 2R,3S,4S stereotriad. This study has also revealed that epimerization at C4, results in a substantial enhancement in β-selectivity (up to β/α 300:1). Copyright
Efficient synthesis of rare sugar D-allal via reversal of diastereoselection in the reduction of protected 1,5-anhydrohex-1-en-3-uloses: Protecting group dependence of the stereoselection
Fujiwara, Takashi,Hayashi, Masahiko
scheme or table, p. 9161 - 9163 (2009/04/04)
(Chemical Equation Presented) D-Allal was selectively obtained by reducing bulky-silyl-protected 1,5-anhydrohex-1-en-3-uloses using the NaBH4 - CeCl3·7H2O system. The crucial point of this synthesis is the nature of the pr
