Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6.
Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6.
Solid State Nucl Magn Reson. 2017 Jul-Aug;84:59-64. doi: 10.1016/j.ssnmr.2016.12.011. Epub 2016 Dec 27.
We report synthesis and solid-state O NMR characterization of four site-specifically O-labeled 2-acylbenzoic acids (2-RC(O)CHCOOH) where R=H and CH): 2-[3-O]formylbenzoic acid, 2-[1,2-O]formylbenzoic acid, 2-[3-O]acetylbenzoic acid, and 2-[1,2,3-O]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-spinning O NMR spectra were recorded at 14.1 and 21.1T for these compounds, from which the O chemical shift and nuclear quadrupolar coupling tensors were determined for each oxygen site. These results represent the first time that O NMR tensors are fully characterized for lactone, cyclic hemiacetal, and cyclic hemiketal functional groups. We also report solid-state O NMR data for the cyclic hemiketal group an anticoagulant drug, warfarin. Experimental O NMR tensors in these compounds were compared with computational results obtained with a periodic DFT code BAND.
我们报告了四种定点 O 标记的 2-酰基苯甲酸（2-RC（O）CHCOOH）的合成和固态 O NMR 表征，其中 R=H 和 CH）：2-[3-O]甲酰基苯甲酸、2-[1,2-O]甲酰基苯甲酸、2-[3-O]乙酰基苯甲酸和 2-[1,2,3-O]乙酰基苯甲酸。在固态中，2-甲酰基和 2-乙酰基苯甲酸均以环状邻苯二甲酸酐形式存在，每种形式都含有一个五元内酯环和一个环状半缩醛/半缩酮基团。在 14.1 和 21.1T 下对这些化合物记录了静态和魔角旋转 O NMR 谱，从中确定了每个氧位的 O 化学位移和核四极耦合张量。这些结果代表了首次对内酯、环状半缩醛和环状半缩酮官能团的 O NMR 张量进行了全面表征。我们还报告了抗凝药物华法林中环状半缩酮基团的固态 O NMR 数据。这些化合物的实验 O NMR 张量与使用周期性 DFT 代码 BAND 获得的计算结果进行了比较。
