Nuclear Magnetic Resonance (NMR), Infrared (IR) and Mass Spectrometry (MS) study of keto-enol tautomerism of isobenzofuran-1(3H)-one derivatives

• Autor(a) principal: Pereira, Wagner Luiz
• Data de Publicação: 2016
• Outros Autores: Pires, Diego Arantes Teixeira, Teixeira, Róbson Ricardo, Figueroa-Villar, José Daniel, Nascimento, Claudia Jorge do
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: https://doi.org/10.1016/j.molstruc.2016.02.015; http://www.locus.ufv.br/handle/123456789/21541
• topic: Keto-enol tautomerism; Isobenzofuran-1(3H)-ones; Phtalides; Solvent effects; Physical state influence; Spectroscopy

The keto-enol tautomerism of 3-(2-hydroxy-4,4-dimethyl-6-oxo-cyclohexen-1-yl)isobenzofuran- 1(3H-one (1), 3-(2-hydroxy-6-oxocyclohex-1-enyl)isobenzofuran-1(3H)-one (2), 3-(2- hydroxy- 4-methyl-6-oxocyclohex-1-enyl)isobenzofuran-1(3H)-one (3), 3-(2-hydroxy-5-oxocyclopent-1-enyl) isobenzofuran-1(3H)-one (4) and 2-(3-oxo-1,3-dihydroisobenzofuran-1-yl)-1H-indene-1,3(2H)-dione (5) were investigated. We noticed that for compounds 1 to 4 only the enol form is observed in solid, in solution or in the gas phase. Their tautomeric equilibria are not affected by the solvent, temperature or physical state. Compound 5 was observed in its keto form in solution (NMR) and solid state (IR). The enol species of 5 was also observed upon Mass Spectrometry analysis. These findings were supported by NMR, IR, MS/MS and molecular modeling analyses.