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Updated: Feb 16, 2026

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
Published on: October 18, 2019
Generation and Stability of the gem-Diol Forms in Imidazole Derivatives Containing Carbonyl Groups. Solid-State NMR
Ayelén Florencia Crespi1, Agustín Jesús Byrne1, Daniel Vega2
1Facultad de Farmacia y Bioquímica, Departamento de Química Orgánica, Universidad de Buenos Aires , Junín 956 (C1113AAD), CABA, Argentina.
Abstract:
The stability of gem-diol forms in imidazolecarboxaldehyde isomers was studied by solid-state nuclear magnetic resonance (ss-NMR) combined with single-crystal X-ray diffraction studies. These methodologies also allowed determining the factors governing the occurrence of such rare functionalization in carbonyl moieties. Results indicated that the position of the carbonyl group is the main factor that governs the generation of geminal diols, having a clear and direct effect on hydration, since, under the same experimental conditions, only 36% of 5-imidazolecarboxaldehydes and 5% of 4-imidazolecarboxaldehydes were hydrated, as compared to 2-imidazolecarboxaldehydes, with which a 100% hydration was achieved. Not only did trifluoroacetic acid favor the addition of water to the carbonyl group but also it allowed obtaining single crystals. Single crystals of the gem-diol and the hemiacetal forms 2-imidazolecarboxaldehyde and N-methyl-2-imidazolecarboxaldehyde, respectively, were isolated and studied through 1H ss-NMR. Mass spectrometry and solution-state NMR experiments were also performed to study the hydration process.
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