Dalterio Richard, Huang Xiaohua Stella, Yu Kuo-Long
Bristol-Myers Squibb Company, Pharmaceutical Research Institute, Wallingford, Connecticut 06492, USA.
Appl Spectrosc. 2007 Jun;61(6):603-7. doi: 10.1366/000370207781269774.
Attenuated total reflection (ATR) Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) data are used to characterize the hydrogen bonding of the secondary amide N-H group of several structurally similar benzoyl derivatives of p-aminobenzoic acid esters (retinoids) in chloroform solution. The amide N-H can form intermolecular hydrogen bonds to several proton acceptors in these molecules or it can form an intramolecular hydrogen bond to a fluorine or oxygen atom in some of the molecules. The concentration dependence of the solution N-H infrared absorption bands is used to determine the formation of intramolecular and/or intermolecular H-bonds. Proton NMR spectra were obtained from deuterated chloroform solutions and the sec-amide N-H resonance was assigned for each compound. The downfield shift in the N-H resonance is correlated to intramolecular H-bond formation. Also, the NMR spectra of fluorine-containing compounds provide J(F-H) through-space coupling values. Using infrared and NMR data, the relative intramolecular hydrogen bond strengths (N-H...F or N-H...O) of the compounds are approximately ranked.
衰减全反射（ATR）傅里叶变换红外（FT-IR）和核磁共振（NMR）数据用于表征对氨基苯甲酸酯（类视黄醇）的几种结构相似的苯甲酰衍生物的仲酰胺N-H基团在氯仿溶液中的氢键作用。酰胺N-H可以与这些分子中的几个质子受体形成分子间氢键，或者在某些分子中与氟或氧原子形成分子内氢键。溶液中N-H红外吸收带的浓度依赖性用于确定分子内和/或分子间氢键的形成。从氘代氯仿溶液中获得质子NMR光谱，并为每种化合物指定仲酰胺N-H共振。N-H共振中的向低场位移与分子内氢键的形成相关。此外，含氟化合物的NMR光谱提供了通过空间的J（F-H）耦合值。利用红外和NMR数据，对这些化合物的相对分子内氢键强度（N-H...F或N-H...O）进行了大致排序。
