V. Mossine, G. Glinsky, M. Feather
Sep 15, 1994
Citations
1
Influential Citations
74
Citations
Quality indicators
Journal
Carbohydrate Research
Abstract
Abstract Amadori compounds (1-amino-1-deoxy- d -fructose derivatives) were prepared by reacting d -glucose with a series of aliphatic amino acids. These include Amadori compounds derived from glycine (1), β-alanine (2), γ-amino butyric acid (3), δ-aminovaleric acid (4), ϵ-aminocaproic acid (5) and Nα-formyl- l -lysine (6). In the FAB mass spectra, molecular-ion clusters as well as fragment ions corresponding to loss of water or CO2 molecules were observed. The 13C NMR spectra indicate that all the compounds are conformationally unstable, but that the predominant from present in solution (D2O) is the β-pyranose form. The 1H NMR spectra of 1 and 2 indicate a slow rotation around the C-1—C-2 bond, possibly as a result of an intramolecular hydrogen bond involving the carboxyl group. The pKa's of all compounds were measured by pH-potentiometric titration in 0.2 M KNO3 solution at 25°C. All compounds showed a decrease in the basicity of their amino groups (in the order of ≈ 1.5 of the Ka value), and 1 and 2 showed a decrease in the basicity of their carboxyl groups (in the order of ≈ 0.2) in comparison with that of parent amino acids.