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An experimental and theoretical NMR study of NH-benzimidazoles in solution and in the solid state: proton transfer and tautomerism.

ABSTRACT: This paper reports the (1)H, (13)C and (15)N NMR experimental study of five benzimidazoles in solution and in the solid state ((13)C and (15)N CPMAS NMR) as well as the theoretically calculated (GIAO/DFT) chemical shifts. We have assigned unambiguously the "tautomeric positions" (C3a/C7a, C4/C7 and C5/C6) of NH-benzimidazoles that, in some solvents and in the solid state, appear different (blocked tautomerism). In the case of 1H-benzimidazole itself we have measured the prototropic rate in HMPA-d 18.

SUBMITTER: Nieto CI

PROVIDER: S-EPMC4142846 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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An experimental and theoretical NMR study of NH-benzimidazoles in solution and in the solid state: proton transfer and tautomerism.

Nieto Carla I CI Cabildo Pilar P García M Ángeles MÁ Claramunt Rosa M RM Alkorta Ibon I Elguero José J

Beilstein journal of organic chemistry 20140716

This paper reports the (1)H, (13)C and (15)N NMR experimental study of five benzimidazoles in solution and in the solid state ((13)C and (15)N CPMAS NMR) as well as the theoretically calculated (GIAO/DFT) chemical shifts. We have assigned unambiguously the "tautomeric positions" (C3a/C7a, C4/C7 and C5/C6) of NH-benzimidazoles that, in some solvents and in the solid state, appear different (blocked tautomerism). In the case of 1H-benzimidazole itself we have measured the prototropic rate in HMPA- ...[more]

PMID: 25161719

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