Studies on Girard Hydrazones. II. Polarographic Reduction Mechanisms of Girard Hydrazones
作者:Masaichiro Masui、Hidenobu Ohmori
DOI:10.1248/cpb.12.877
日期:——
Polarographic reduction processes of Girard hydrazones of aliphatic and aromatic ketones were studied. From the results of controlled potential electrolysis, the two-electron reduction process proposed by Prelog and Hafliger for Girard-T Hydrazones of aliphatic and alicyclic ketones was found to be not correct, and a mechanism shown in scheme (4) containing a four-electron reduction process was proposed instead. In the case of the Girard hydrazones of aromatic ketones, the electrode reaction processes seem to be more complicated than the aliphatic series : A reduction mechanism shown as scheme (6) containing four and two-electron reduction processes has been proposed. These mechanisms can explain the polarographic behaviours of Girard hydrazones most adequately. In connection with this study, ultraviolet absorption spectra of Girard hydrazones were measured under various conditions. The molecular forms of Girard hydrazones under the experimental conditions have been discussed from the results.
研究了脂肪族和芳香族酮的吉拉尔肼的极谱还原过程。从受控电势电解的结果来看,Prelog 和 Hafliger 提出的脂肪族和脂环族酮的吉拉尔肼的双电子还原过程并不正确,因此提出了如方案 (4) 所示的包含四电子还原过程的机理。对于芳香族酮的吉拉尔肼,电极反应过程似乎比脂肪族系列更为复杂:有人提出了如方案 (6) 所示的还原机理,其中包含四电子和双电子还原过程。这些机制可以最充分地解释吉拉尔肼的极谱行为。为配合这项研究,我们在不同条件下测量了吉拉尔肼的紫外吸收光谱。根据结果讨论了吉拉尔肼在实验条件下的分子形式。