Abstract
The kinetics of the mutarotation of xylose, and series of 6-substituted 6-deoxy-glucoses, and a series of 2-substituted 2-deoxy-glucoses catalysed by oxonium ion, water, 4-substituted pyridines, 2,6-Iutidine, Tris, 2,2′-iminodiethanol, and morpholine have been measured. Electron-withdrawing substituents at the 6-position decreased the rate of mutarotation catalysed by oxonium ion and by water but increased that of the mutarotation catalysed by bases. Electron-withdrawing substituents at the 2-position decreased the rate of mutarotation with all the catalysts studied except in the case of the 2,6-Iutidine-catalysed reaction of 2-amino-2-deoxy-D-glucose hydrochloride, which occurred slightly faster than that of 2-deoxy-D-glucose. The mechanisms of these mutarotations are discussed in the light of these substituent effects, the solvent-isotope effect, and the diffusion-controlled limit of the rate of bimolecular reactions. Steric-hindrance factors were calculated for the 2,6-Iutidine-catalysed reactions but there appears to be no correlation between these and the size of the 2- or the 6-substituents.Intramolecular catalysis was found for the mutarotation of 6-deoxy-D-gluco-hepturonic acid and 6-O-(o-hydroxyphenyl)-D-glucose.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of the Chemical Society, Perkin Transactions 2
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
