title: The tautomerism of Omeprazole in solution: a 1H and 13C NMR study.
abstract: The tautomerism of 5(6)-methoxy-2-([(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl] sulfinyl)-1H-benzimidazole (omeprazole) was determined in solution, K(T) = 0.59 in THF at 195 K, in favor of the 6-methoxy tautomer. The assignment of the signals was made by comparison with its two N-methyl derivatives in acetone-d6 and through theoretical calculations of the absolute shieldings (GIAO/DFT/6-311++G**).
authors.affiliation: Departamento de Química Orgánica y Biología, Facultad de Ciencias, UNED, Senda del Rey 9, E-28040 Madrid, Spain. ibon@iqm.csic.es
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Claramunt
authors.forename: Concepción
authors.initials: C
authors.lastname: López
authors.forename: Ibon
authors.initials: I
authors.lastname: Alkorta
authors.forename: José
authors.initials: J
authors.lastname: Elguero
authors.forename: Rong
authors.initials: R
authors.lastname: Yang
authors.forename: Steve
authors.initials: S
authors.lastname: Schulman
mesh_terms: D002247:Carbon Isotopes; D006859:Hydrogen; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D009853:Omeprazole / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry
chemical_list: D002247:Carbon Isotopes; D012996:Solutions; D006859:Hydrogen; D009853:Omeprazole