Related Experiment Video
Updated: Feb 9, 2026
06:00
One-pot Microwave-assisted Conversion of Anomeric Nitrate-esters to Trichloroacetimidates
Published on: January 15, 2018
7.9K
NMR analyses of complex d-glucose anomerization
Martin Kaufmann1, Clemens Mügge2, Lothar W Kroh1
1Berlin Institute of Technology, Department of Food Chemistry and Food Analysis, Gustav-Meyer-Allee 25, TIB 4/3-1, D-13355 Berlin, Germany.
Food Chemistry
|June 10, 2018
Summary
This study quantifies d-glucose anomers and their thermodynamic parameters using NMR. Furanoid anomers significantly impact d-glucose reactivity, and sugar solution reactivity depends on reaching equilibrium.
Area of Science:
- Carbohydrate Chemistry
- Physical Organic Chemistry
- Nuclear Magnetic Resonance Spectroscopy
Background:
- Understanding the anomeric equilibrium and reactivity of d-glucose is crucial in carbohydrate chemistry.
- Previous studies have explored d-glucose anomerization, but quantitative data on furanoid anomer influence and ring-opening kinetics are limited.
Purpose of the Study:
- To determine resonance frequencies and relative concentrations of d-glucose anomers.
- To calculate thermodynamic parameters and measure ring-opening rate constants.
- To investigate the influence of furanoid anomers on d-glucose reactivity and the time-dependent nature of its equilibrium.
Main Methods:
- Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy was employed to analyze d-glucose.
- Temperature-dependent 1H NMR was used to determine anomeric proton resonance frequencies and quantify anomer concentrations.
- 1H selective blind saturation transfer NMR spectroscopy was utilized to measure ring opening rate constants.
Main Results:
- Resonance frequencies and relative concentrations of five d-glucose anomers were determined as a function of temperature.
- Thermodynamic parameters for d-glucose anomers were calculated.
- Ring opening rate constants for cyclic d-glucose anomers were measured for the first time, indicating a significant influence of furanoid anomers on overall reactivity.
- Anomeric equilibration curves revealed that the reactivity of d-glucose solutions is time-dependent until thermodynamic equilibrium is achieved.
Conclusions:
- Furanoid d-glucose anomers play a critical role in the overall reactivity of d-glucose.
- The reactivity of reducing sugar solutions, including d-glucose, is influenced by the time required to reach thermodynamic equilibrium.
- This study provides novel insights into the dynamic behavior and reactivity of d-glucose anomers.
Related Concept Videos
01:13¹H NMR: Complex Splitting
1.9K
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
1.9K
01:02Glucose Homeostasis: Regulation of Blood Glucose
4.3K
Carbohydrates consumed through foods are converted into glucose, a crucial energy source for the body. In the prandial state, high blood glucose levels stimulate the secretion of insulin from the pancreas. Insulin inhibits hepatic glucose production and stimulates glucose uptake and metabolism by muscle and adipose tissue. The excess glucose is converted into glycogen and stored in the liver and muscles.
During fasting, when blood glucose levels are low, the pancreas secretes glucagon. it...
During fasting, when blood glucose levels are low, the pancreas secretes glucagon. it...
4.3K
01:27Glucose Transporters
27.6K
Glucose transporters facilitate the transport of glucose across the cell membrane. In addition to glucose, some glucose transporters can also aid the movement of other hexoses such as fructose, mannose, and galactose.
Facilitated diffusion-glucose transporters (GLUTs) are encoded by the solute-linked carrier (SLC) family 2, subfamily A gene family, or SLC2A. The 14 GLUT protein members are distributed into three classes:
Facilitated diffusion-glucose transporters (GLUTs) are encoded by the solute-linked carrier (SLC) family 2, subfamily A gene family, or SLC2A. The 14 GLUT protein members are distributed into three classes:
27.6K
01:04¹³C NMR: ¹H–¹³C Decoupling
1.8K
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
1.8K
01:15¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
1.7K
The axial and equatorial protons in cyclohexane can be distinguished by performing a variable-temperature NMR experiment. In this process, except for one proton, the remaining eleven protons are replaced by deuterium. The deuterium substitution avoids the possible peak splitting caused by the spin-spin coupling between the adjacent protons. The remaining proton flips between the axial and equatorial positions.
1.7K
01:26Glucose Absorption Into the Small Intestine
35.9K
Complex carbohydrates consumed cannot be absorbed into the small intestine in their original form. First, they must be hydrolyzed to a monosaccharide form such as glucose or galactose. These monosaccharides are then transported across the intestinal membrane and into the blood via transcellular transport. The intestinal epithelial cells allow the movement of these monosaccharides with a defined 'entry' through membrane transporter proteins present on their apical membrane and...
35.9K