ペンタクロルベンズアルドキシム異性体の構造およびその分離定量

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書誌事項

タイトル別名
  • Structure of pentachlorobenzaldoxime isomers and their separation and determination
  • ペンタクロルベンズアルドキシム イセイタイ ノ コウゾウ オヨビ ソノ ブンリ テイリョウ
  • Analytical studies on pesticides and related compounds. XVII
  • 農薬および関連化合物の分析に関する研究(第17報)

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説明

The physical and chemical properties of two geometrical isomers of pentachlorobenzaldoxime (Minokol) were studied and it was suggested that Minokol ordinarily synthesized gave syn configuration (hydroxyl group cis to methine hydrogen).<BR>NMR spectra of syn and anti Minokols in DMSO showed a difference of 0.66 ppm in the chemical shift for the CH hydrogen, which resonated at a higher field in anti Minikol than in the syn isomer owing to paramagnetic anisotropy effect of hydroxyimino group. The anti hydrogen of the hydroxyl group shifted 0.23 ppm to a higher field than the syn hydrogen. It suggested that hydroxyimino group of Minokol was not coplanar to phenyl group, the anti hydrogen was over the benzene ring and was shielded on account of peripheral paramagnetic effect of aromatic ring current. UV spectra supported the results of NMR spectra. The absorption maximum of Minokol was at shorter wave lenght (230 mμ) than those of other non-ortho-substituted benzaldoximes and π-electrons of phenyl and hydroxyimino groups were less conjugated than other oximes. The associated OH stretching frequency near 3280 cm-1 in syn Minokol was displaced towards lower frequency in the anti isomer to near 3210 cm-1, which indicated that the anti oxime associated to longer chain than the syn oxime. The polarographic half waves on syn and anti Minokols in the media of N, Ndimethylformamide-0.5 N HCl-water (15 : 5 : 5) were -0.595 and -0.756 volts vs. S. C. E., respectively.<BR>Both isomers of Minokol were separated from each other by thin layer chromatography (TLC) and Rf values of the anti isomer were higher than those of the syn one by various developing solvents.<BR>Each of syn and anti Minokols in tetrahydrofuran solution was irradiated by a UV lamp (253.6 mμ) and separated by TLC and determined polarographically. Both Minokols were converted to the corresponding isomers to each other and the ratio of anti to syn reached constant (anti>syn). Minokol has been reported to give much more fungicidal toxicity outdoors than indoors and the fact mentioned above suggested that syn Minokol was converted to the anti isomer and gave more toxicity.

収録刊行物

  • 分析化学

    分析化学 21 (6), 736-740, 1972

    公益社団法人 日本分析化学会

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