title: Solid-state17O NMR study of 2-acylbenzoic acids and warfarin.
abstract: We report synthesis and solid-state17O NMR characterization of four site-specifically17O-labeled 2-acylbenzoic acids (2-RC(O)C6H4COOH) where R=H and CH3): 2-[3-17O]formylbenzoic acid, 2-[1,2-17O2]formylbenzoic acid, 2-[3-17O]acetylbenzoic acid, and 2-[1,2,3-17O3]acetylbenzoic acid. In the solid state, both 2-formyl- and 2-acetyl-benzoic acids exist as the cyclic phthalide form each containing a five-membered lactone ring and a cyclic hemiacetal/hemiketal group. Static and magic-angle-spinning17O NMR spectra were recorded at 14.1 and 21.1T for these compounds, from which the17O chemical shift and nuclear quadrupolar coupling tensors were determined for each oxygen site. These results represent the first time that17O NMR tensors are fully characterized for lactone, cyclic hemiacetal, and cyclic hemiketal functional groups. We also report solid-state17O NMR data for the cyclic hemiketal group an anticoagulant drug, warfarin. Experimental17O NMR tensors in these compounds were compared with computational results obtained with a periodic DFT code BAND.
authors.affiliation: Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6.
authors.forename: Xianqi
authors.initials: X
authors.lastname: Kong
authors.affiliation: Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6.
authors.forename: Yizhe
authors.initials: Y
authors.lastname: Dai
authors.affiliation: Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6. Electronic address: gang.wu@chem.queensu.ca.
authors.forename: Gang
authors.initials: G
authors.lastname: Wu
mesh_terms: D019817:Benzoic Acid / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010103:Oxygen Isotopes; D011789:Quantum Theory; D014859:Warfarin / Q000737:chemistry*
chemical_list: D010103:Oxygen Isotopes; C000615258:Oxygen-17; D014859:Warfarin; D019817:Benzoic Acid
keywords: (17)O NMR; Chemical shift tensor; Hemiacetal; Hemiketal; Lactone; Quadrupolar coupling tensor; Solid state; Warfarin