Geometrical Isomerism of Phenylhydrazones of α-Keto Esters. II.p-Substituted Phenylhydrazones of Ethyl Pyruvate and 2,4-Dinitrophenylhydrazones of Some α-Keto Esters

Autor:	Takeo Nashima, Fumihide Ishibashi, Keiko Yamamoto, Shigeko Sasaki, Yoshimi Kitagawa, Masako Yoshikawa, Yoshinori Ichihara, Junko Nishino, Atsuko Matsuoka, Ikuko Kobayashi
Rok vydání:	1986
Předmět:	chemistry.chemical_classification Solvent chemistry Hydrogen bond Intramolecular force Proton NMR Hydrazone Organic chemistry General Chemistry Nuclear magnetic resonance spectroscopy Aliphatic compound Medicinal chemistry Cis trans isomerization
Zdroj:	Bulletin of the Chemical Society of Japan. 59:73-76
ISSN:	1348-0634 0009-2673
DOI:	10.1246/bcsj.59.73
Popis:	Each geometrical isomer of various substituted phenylhydrazones of ethyl pyruvate and 2,4-dinitrophenylhydrazones of some α-keto esters was isolated in a pure state. Partial isomerizations of the E-isomers of the former hydrazones to the Z-isomers took place by keeping solutions of the hydrazones in organic solvents containing C, H, and Cl in the dark. An E- or Z-structure was assigned to each 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 as that proposed in a previous investigation.
Databáze:	OpenAIRE
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