Observation of the keto tautomer of d-fructose in D2O using 1H NMR spectroscopy

摘要: Abstract d -Fructose was analysed by NMR spectroscopy and previously unidentified 1H resonances were assigned to the keto α-pyranose tautomers. The full assignment of shifts for various fructose tautomers enabled use in studies mutarotation (5–25 °C) tautomeric composition at equilibrium (5–50 °C). β-pyranose furanose D2O a concentration 0.18 M found have an activation energy 62.6 kJ mol−1. At (20 °C D2O) distribution β-pyranose, β-furanose, α-furanose, be 68.23%, 22.35%, 6.24%, 2.67% 0.50%, respectively. This not significantly affected varying concentrations between 0.089 0.36 M or acidification pH 3. Upon equilibrating 6 temperatures 5 50 °C there linear relationship change temperature all forms.