CONFORMATIONAL STUDY OF ESTERS AND RELATED COMPOUNDS

建议的研究分为六个部分，每个部分 涉及到动态核磁共振波谱在下列问题中的应用 构象分析。前三部分的项目是 有望提供实验证据，证明“芳香性”是 对稳定酯类化合物的Z构象很重要，次要 酰胺(蛋白质)及相关化合物。乙烯基、乙炔基、苯基和 环丙基预计不能提供 第三对电子完成芳香族六重态，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。这个 已知控制芳香酰胺构象的能力是 在药物设计中很有用，拟议的研究是可望的 提供一组组，这些组可用于更改 某些酯、酰胺和相关化合物的构象 除了有助于理解构象 三类重要生物化合物的偏好 (酰胺、酯和硫代酯)。 在第一部分中，将介绍低温17O、14N和13C核磁共振波谱 用于研究硫氰酸根和亚硒酸根中的E-Z异构体。零件 II描述了构象的~(13)C和~1H核磁共振研究 在几种硫代乙酸酯中的平衡。在第三部分， 一种羧酸和一种硫醇酸的乙酰酯将是 用~1H和~(13)C核磁共振进行了研究。第四部分、第五部分和第六部分介绍了 三氟硫代乙酸，几种环己基化合物，可以 E-Z和轴-赤道异构体，以及几种内酯， 分别进行了分析。

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.