Geometrical Isomerism of Phenylhydrazones of α-Keto Esters. II.<i>p</i>-Substituted Phenylhydrazones of Ethyl Pyruvate and 2,4-Dinitrophenylhydrazones of Some α-Keto Esters
作者:Fumihide Ishibashi、Takeo Nashima、Junko Nishino、Ikuko Kobayashi、Yoshinori Ichihara、Yoshimi Kitagawa、Shigeko Sasaki、Masako Yoshikawa、Atsuko Matsuoka、Keiko Yamamoto
DOI:10.1246/bcsj.59.73
日期:1986.1
molecule on the basis of IR and 1H NMR spectra. In all cases, isomers with higher Rf-values on a silica gel TLC (using benzene as a developing solvent) involved an intramolecular hydrogen bonding between the imino hydrogen and the ester carbonyl oxygen. Thus, the Z-structure was assigned. An E-structure was assigned to other isomers with lower Rf-values. The present assignment is, thus, entirely the same
丙酮酸乙酯的各种取代苯腙和一些α-酮酯的2,4-二硝基苯腙的每种几何异构体均以纯态分离。通过将腙在含有 C、H 和 Cl 的有机溶剂中的溶液保持在黑暗中,使前腙的 E-异构体部分异构化为 Z-异构体。根据 IR 和 1H NMR 光谱,每个分子都具有 E 或 Z 结构。在所有情况下,在硅胶 TLC(使用苯作为展开溶剂)上具有较高 Rf 值的异构体涉及亚氨基氢和酯羰基氧之间的分子内氢键。因此,指定了 Z 结构。E 结构被分配给具有较低 Rf 值的其他异构体。因此,目前的分配与先前调查中提出的分配完全相同。