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Favipiravir-Tautomeric and Complexation Properties in Solution.
Vera Deneva1,2, Sofia Slavova1,3, Alina Kumanova1
1Institute of Electronics, Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria.
Pharmaceuticals (Basel, Switzerland)
|January 21, 2023
Summary
Favipiravir
Area of Science:
- Medicinal Chemistry
- Physical Chemistry
- Computational Chemistry
Background:
- Favipiravir is an antiviral medication.
- Understanding its tautomeric properties is crucial for drug design and formulation.
- Previous studies lacked experimental investigation into its tautomerism.
Purpose of the Study:
- To experimentally determine the tautomeric properties of favipiravir.
- To investigate the influence of solvents and metal ions on favipiravir's tautomeric equilibrium.
- To elucidate the complexation mechanism with alkaline-earth-metal ions.
Main Methods:
- Molecular spectroscopy: UV-Vis absorption, fluorescence, and Nuclear Magnetic Resonance (NMR).
- Density Functional Theory (DFT) quantum-chemical calculations.
- Investigation of interactions with various organic solvents, water, and alkaline-earth-metal ions.
Main Results:
- The enol tautomer of favipiravir is more stable in most organic solvents.
- The keto tautomer is favored in water due to specific solute-solvent interactions.
- Deprotonation and 2:1 ligand:metal complex formation occur upon addition of alkaline-earth-metal ions.
Conclusions:
- Favipiravir exhibits distinct tautomeric preferences based on solvent environment.
- Specific solute-solvent interactions dictate tautomer stability in aqueous media.
- Alkaline-earth-metal ions form stable complexes with favipiravir via a size-fit effect, capturing the metal ion between carbonyl groups.
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