CONFORMATIONAL STUDY OF ESTERS AND RELATED COMPOUNDS

本研究共分为六个部分， 涉及应用动态核磁共振光谱学的问题， 构象分析 前三部分的项目分别是 预计将提供实验证据表明，“芳香性”是 重要的是稳定酯的Z构象，仲 酰胺（蛋白质）和相关化合物。 乙烯基、乙炔基、苯基和 预期环丙基不能提供环丙基化。 第三对电子来完成芳香族六重体，以及 含有这些基团的化合物将被研究，以确定 E-异构体的数量是否如预期的那样大。 的 已知控制芳族酰胺构象的能力 在药物设计中有用，并且预期所提出的研究 以提供一组可用于改变 某些酯、酰胺和相关化合物的构象， 除了有助于理解构象 三种重要的生物化合物的偏好 （酰胺、酯和硫酯）。 在第一部分中，低温17 O，14 N和13 C NMR光谱将被 用于研究亚硫硝和亚硒硝的E-Z异构现象。 部分 II描述了通过13 C和1H NMR研究的构象 在几种乙酸硫酯中平衡。 在第三部分中， 羧酸和硫醇酸的炔属酯将是 通过1H和13 C NMR研究。 第四、五和六部分介绍了 三氟硫代乙酸，几种环己基化合物， E-Z和轴向-赤道异构体，以及几种内酯， 分别

The proposed research is divided into six parts, each of which involves the application of dynamic NMR spectroscopy to problems in conformational analysis. The projects of the first three parts are expected to provide experimental evidence that "aromaticity" is important for stabilizing the Z conformations of esters, secondary amides (proteins), and related compounds. Vinyl, ethynyl, phenyl and cyclopropyl groups are expected to be incapable of providing the third pair of electrons to complete the aromatic sextet, and compounds containing these groups will be studied to determine whether the populations of E-isomers are large, as expected. The ability to control the conformation of aromatic amides is known to be useful in the design of drugs, and the proposed research is expected to provide a set of groups which can be used to change the conformation of certain esters, amides, and related compounds, in addition to contributing to an understanding of the conformational preferences of three important classes of biological compounds (amides, esters, and thioesters). In part I, low-temperature 17O, 14N, and 13C NMR spectroscopy will be used to study E-Z isomerism in thionitries and a selenonitrite. Part II describes a study by 13C and 1H NMR of conformational equilibration in several thioesters of acetic acid. In part III, acetylenic esters of a carboxylic acid and a thiol acid will be studied by 1H and 13C NMR. Parts IV, V and VI describes studies of trifluorothioacetic acid, several cyclohexyl compounds that can have both E-Z and axial-equatorial isomers, and several lactones, respectively.