Ab initio and Density Functional Calculations on the Ring-Chain Tautomerism of γ-Oxocarboxylic Acids

Abstract

Keywords: Ab initio calculations / γ-Oxocarboxylic acids / Density functional calculations / Substituent effects / Tautomerism The results of ab initio (HF, MP2) and density functional (B3LYP) calculations on a series of γ-oxocarboxylic acids [(Z)-3-acetyl or benzoylacrylic and 2-acetyl or benzoylbenzoic acids] A and their cyclic tautomers B are presented. For the open-chain tautomers, different rotamers were considered.Bulk solvent effects were considered by using the polarised continuum model (PCM) and were found to be essential for a [a]

Mechanistic Insight into C-Nucleophiles Addition to 2-Formylbenzoic Acid in Water Media: A DFT Study.

“…This equilibrium has been studied previously both experimentally 69 and through DFT calculations. 70 Our results indicate that, in an aqueous environment, the cyclic lactol form 6 is more stable than the open-chain form 7 by 1.9 kcal/mol (Figure 3), consistent with previously reported results. For the protonated lactol form 6, two conformers 8 and 9 were identified.…”

Mechanistic Insight into C-Nucleophiles Addition to 2-Formylbenzoic Acid in Water Media: A DFT Study.

“…This equilibrium has been studied previously both experimentally 69 and through DFT calculations. 70 Our results indicate that, in an aqueous environment, the cyclic lactol form 6 is more stable than the open-chain form 7 by 1.9 kcal/mol (Figure 3), consistent with previously reported results. For the protonated lactol form 6, two conformers 8 and 9 were identified.…”

A computational study of base-catalyzed reactions of cyclic 1,2-diones: cyclobutane-1,2-dione

“…The anticipated product P3 of path C is a γ-oxocarboxylate. Such γ-oxocarboxylic acids or carboxylates are prone to ring–chain tautomerism [32–33]. Product P3a essentially is the ion-dipole complex between the ring tautomer of neutral γ-oxobutanoic acid with [OH(H 2 O) 5 ] – , and hence, its formation is completely reasonable.…”

Mechanistic Insight into C-Nucleophiles Addition to 2-Formylbenzoic Acid in Water Media: A DFT Study.

“…This equilibrium has been studied previously both experimentally 69 and through DFT calculations. 70 Our results indicate that, in an aqueous environment, the cyclic lactol form 6 is more stable than the open-chain form 7 by 1.9 kcal/mol (Figure 3), consistent with previously reported results. For the protonated lactol form 6, two conformers 8 and 9 were identified.…”

A computational study of base-catalyzed reactions of cyclic 1,2-diones: cyclobutane-1,2-dione

“…The anticipated product P3 of path C is a γ-oxocarboxylate. Such γ-oxocarboxylic acids or carboxylates are prone to ring–chain tautomerism [32–33]. Product P3a essentially is the ion-dipole complex between the ring tautomer of neutral γ-oxobutanoic acid with [OH(H 2 O) 5 ] – , and hence, its formation is completely reasonable.…”

Mechanistic Insight into C-Nucleophiles Addition to 2-Formylbenzoic Acid in Water Media: A DFT Study.

“…This equilibrium has been studied previously both experimentally 69 and through DFT calculations. 70 Our results indicate that, in an aqueous environment, the cyclic lactol form 6 is more stable than the open-chain form 7 by 1.9 kcal/mol (Figure 3), consistent with previously reported results. For the protonated lactol form 6, two conformers 8 and 9 were identified.…”

A computational study of base-catalyzed reactions of cyclic 1,2-diones: cyclobutane-1,2-dione

“…The anticipated product P3 of path C is a γ-oxocarboxylate. Such γ-oxocarboxylic acids or carboxylates are prone to ring–chain tautomerism [32–33]. Product P3a essentially is the ion-dipole complex between the ring tautomer of neutral γ-oxobutanoic acid with [OH(H 2 O) 5 ] – , and hence, its formation is completely reasonable.…”