Related Experiment Video
Updated: Aug 24, 2026

Dissolution Dynamic Nuclear Polarization Instrumentation for Real-time Enzymatic Reaction Rate Measurements by NMR
Published on: February 23, 2016
Differential protonation and dynamic structure of doxylamine succinate in solution using 1H and 13C NMR
B S Somashekar1, G A Nagana Gowda, A R Ramesha
1Centre of Biomedical Magnetic Resonance, Sanjay Gandhi Post-graduate Institute of Medical Sciences, Raebareli Road, Lucknow 226 014, India.
Abstract:
A protonation and dynamic structural study of doxylamine succinate, a 1:1 salt of succinic acid with dimethyl-[2-(1-phenyl-1-pyridin-2-yl-ethoxy)ethyl]amine, in solution using one- and two-dimensional 1H and 13C NMR experiments at variable temperature and concentration is presented. The two acidic protons of the salt doxylamine succinate are in 'intermediate' exchange at room temperature, as evidenced by the appearance of a broad signal. This signal evolves into two distinct signals below about -30 degrees C. A two-dimensional 1H-1H double quantum filtered correlation experiment carried out at -55 degrees C shows protonation of one of the acidic protons to the dimethylamine nitrogen. A two-dimensional rotating frame 1H-1H NOE experiment at the same temperature reveals that the other proton remains with the succinate moiety. Comparison of the 1H and 13C chemical shifts and the 13C T1 relaxation times of the salt with those of the free base further substantiate the findings.
More Related Videos
Related Concept Videos
¹H NMR of Labile Protons: Deuterium (²H) Substitution
NMR Spectroscopy Of Amines
¹H NMR: Complex Splitting
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 first.
Proton (¹H) NMR: Chemical Shift
Absorption signals of all the protium nuclei in a...
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
¹H NMR of Labile Protons: Temporal Resolution
The –OH proton in alcohols typically appears in the range of δ 2 to 5 ppm but can vary depending on the specific...

