Structure–reactivity relationship of Amadori rearrangement products compared to related ketoses. (16th June 2016)

• Record Type: Journal Article
• Authors: Kaufmann, Martin; Meissner, Philipp M.; Pelke, Daniel; Mügge, Clemens; Kroh, Lothar W.
• Is Part Of: Carbohydrate research. Volume 428(2016)
• Page Start: 87
• Page End: 99
• Publication Date: 2016-06-16
• Subjects: Isomerisation dynamics -- Reactivity -- Dynamic NMR spectroscopy -- d-Fructose -- Amadori compound -- Ring inversion; d-Fructose (PubChem CID: 5984) -- d-Tagatose (PubChem CID: 92092) -- d-Fructose + l-Proline (PubChem CID: 118797558) -- N-(1-deoxy-d-fructos-1-yl)-l-proline (PubChem CID: 71316983) -- N-(1-deoxy-d-fructos-1-yl)-l-alanine (PubChem CID: 71316979) -- N-(1-deoxy-d-fructos-1-yl)-l-phenylalanine (PubChem CID: 71316982); Carbohydrates -- Periodicals; Chemistry, Organic -- Periodicals; Biochemistry -- Periodicals; Carbohydrates -- Periodicals; Chimie organique -- Périodiques; Glucides -- Périodiques; Biochemistry; Carbohydrates; Chemistry, Organic; Periodicals; Electronic journals; 507.78
• DOI: 10.1016/j.carres.2016.04.016
• Languages: English
• ISSNs: 0008-6215

Abstract

Highlights: Sugar degradation kinetics are related to isomerisation dynamics. Amadori rearrangement products show complex isomerisation/mutarotation. Isomerisation rates depend on C-1 substituent mediated intramolecular catalysis. Fast 5 C2 ↔ 2 C5 ring inversion occurs in case ofd -fructose-derived α-pyranoses. Graphical abstract: Abstract: Structure-reactivity relationships of Amadori rearrangement products compared to their related ketoses were derived from multiple NMR spectroscopic techniques. Besides structure elucidation of six Amadori rearrangement products derived fromd -glucose andd -galactose withl -alanine, l -phenylalanine andl -proline, especially quantitative 13 C selective saturation transfer NMR spectroscopy was applied to deduce information on isomeric systems. It could be shown exemplarily that the Amadori compound N -(1-deoxy-d -fructos-1-yl)-l -proline exhibits much higher isomerisation rates thand -fructose, which can be explained by C-1 substituent mediated intramolecular catalysis. In combination with a reduced carbonyl activity of Amadori compounds compared to their related ketoses which results in an increased acyclic keto isomer concentration, the results on isomerisation dynamics lead to a highly significant increased reactivity of Amadori compounds. This can be clearly seen, comparing approximated carbohydrate milieu stability time constants ( ACuSTiC ) which is 1 s for N -(1-deoxy-d -fructos-1-yl)-l -proline and 10 s ford -fructose at pD 4.20 ± 0.05 at 350 K. In addition, first NMR spectroscopic data are provided, which prove that α-pyranose of (amino acid substituted)d -fructose adopts both, 2 C5 and 5 C2 conformation.