Complete 1H and 13C NMR Assignment of the ent-Labdane 2α-Hydroxyeperuic Acid Combining Conventional NMR Methods and
Francisco Juárez-Carrillo1, Hugo A García-Gutiérrez1, Mónica Luna-Vázquez1
1Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, Mexico.
Magnetic Resonance in Chemistry : MRC
|March 11, 2025
Summary
Nuclear magnetic resonance (NMR) spectral assignment for ent-labdane 2α-hydroxyeperuic acid was completed using spin simulation. This method combined experimental NMR data with computational analysis for accurate structural elucidation of complex natural products.
Area of Science:
- Organic Chemistry
- Natural Product Chemistry
- Spectroscopy
Background:
- Natural products often exhibit complex structures, posing challenges for complete structural elucidation.
- Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful tool for determining molecular structures.
- Signal overlapping in NMR spectra of complex molecules like natural products can hinder accurate assignment.
Purpose of the Study:
- To achieve the complete assignment of 1H and 13C NMR spectra for ent-labdane 2α-hydroxyeperuic acid.
- To demonstrate the utility of combining experimental NMR data with spin simulation for spectral assignment.
- To validate the use of Cosmic Truth (CT) software and 1H iterative full-spin analysis (HiFSA) in complex spectral analysis.
Main Methods:
- Acquisition of conventional NMR data: 1H, 13C, HSQC, HMBC, COSY, NOESY, 1D-TOCSY, and J-resolved (Jres).
- Application of 1H iterative full-spin analysis (HiFSA) using the prerelease version of Cosmic Truth (CT) web-based software.
- Integration of experimental NMR data with spin simulation for spectral assignment.
Main Results:
- Successful and complete assignment of 1H and 13C NMR spectra for ent-labdane 2α-hydroxyeperuic acid (3).
- Demonstrated efficacy of spin simulation in resolving complex spectral assignments with overlapping signals.
- Validation of CT software and HiFSA for advanced NMR spectral analysis.
Conclusions:
- The combined approach of experimental NMR data and spin simulation provides a robust method for complete spectral assignment.
- This strategy is particularly effective for complex natural products where signal overlap is a significant challenge.
- The study highlights the potential of computational tools like CT and HiFSA in advancing NMR-based structural elucidation.
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