Nuclear Magnetic Resonance Spectra of α-D-Glucans in the Presence of 1,1,3,3-Tetramethylurea

概要

論文の詳細を見る
1,1,3,3-Tetramethylurea (Me_4U) promotes the alkylation of α-D-glucans and prevents caramelization and side reactions in acetolysis and acid hydrolysis of α-D-glucans even at high reaction temperatures. This might be caused by strong intermolecular hydrogen bondings between hydroxyls of carbohydrates and the carbonyl group of Me_4U, which prevail over intramolecular hydrogen bondings between the alcoholic hydroxyls. The hydrogen bondings as such induce deformation of the rigid higher structure of polyglucans to promote the alkylation, while they protect hydroxyls from side reactions during the course of modified acetolysis and acid hydrolysis even at high temperature to produce oligosaccharide fragments in good yields.In the present study the interaction betwen Me_4U and hydroxyls of glucans has been demonstrated by means of proton and carbon-13 nuclear magnetic resonance (^1H- and ^<13>C-NMR) spectroscopy.The ^1H- and ^<13>C-NMR spectra of carbohydrates remain unchanged even after heating for 30 min at 160℃ in the presence of d_<12>-Me_4U in d_6-dimethyl sulfoxide, whereas without d_<12>-Me_4U in the medium, heating the solution causes remarkable changes.
社団法人日本薬学会の論文
1988-04-25