153448-98-7Relevant academic research and scientific papers
Boronic Acids as Phase-Transfer Reagents for Fischer Glycosidations in Low-Polarity Solvents
Manhas, Sanjay,Taylor, Mark S.
, p. 11406 - 11417 (2017/11/10)
Protocols employing phenylboronic acid as a phase-transfer reagent for Fischer glycosidations in low-polarity organic solvents are described. In addition to providing rate acceleration, the formation of a substrate-derived boronic ester alters the course of the reaction by selective promotion of a furanoside- or pyranoside-selective pathway. Computational modeling of the relative energies of the glycoside-derived boronic esters provides results that are qualitatively consistent with the observed distributions of furanoside versus pyranoside products. The boronic esters that are obtained as direct products of these reactions serve as protected intermediates for the synthesis of functionalized glycosides. Complexation of particular diol groups by the boronic acid also enables selective transformations of mixtures of carbohydrates.
Enzymic transfer of 6-modified D-galactosyl residues: Synthesis of biantennary penta- and hepta-saccharides having two 6-deoxy-D-galactose residues at the nonreducing end and evaluation of 6-deoxy-D-galactosyl transfer to glycoprotein using bovine β-(1 4)-galactosyltransferase and UDP-6-deoxy-D-galactose
Kajihara,Endo,Ogasawara,Kodama,Hashimoto
, p. 273 - 294 (2007/10/02)
UDP-6-Deoxy-D-galactose and UDP-6-deoxy-6-fluoro-D-galactose were synthesized and their transfer to 2-acetamido-2-deoxy-D-glucose (N-acetyl-D-glucosamine) by β-(1 → 4)-galactosyltransferase was examined. The transfer rates of 6-deoxy-D-galactose and 6-deoxy-6-fluoro-D-galactose were 1.3 and 0.2% of that of D-galactosyl transfer, respectively. The 2-acetamido-4-O-(6-deoxy-β-D-galactopyranosyl)-2-deoxy-D-glucopyranos e (6'-deoxy-N-acetyllactosamine) and methyl 2-acetamido-4-O-(6-deoxy-6-fluoro-β-D-galactopyranosyl)-2-deoxy-D-glu copyranoside (6'-deoxy-6'-fluoro-N-acetyllactosamine) were synthesized enzymatically in 30 and 59% yields, respectively. Further, 6-deoxy-D-galactose could be completely transferred to N-linked type biantennary oligosaccharides having two N-acetyl-D-glucosaminyl residues at the nonreducing end to give the corresponding penta- and hepta-saccharides in 55 and 57% yields, respectively. An assay of 6-deoxy-D-galactosyl transfer using asialo agalacto α1-acid glycoprotein as an acceptor suggested that 6-deoxy-D-galactose was transferred to about 30% of the N-acetyl-D-glucosaminyl residues in the N-linked oligosaccharides of the glycoprotein.
