• Title/Summary/Keyword: Polar substituent constant

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Substituent Effect on the Fungicidal Activity of New N-substituted Benzotriazol-1-yl Derivatives (새로운 N-치환 benzotriazol-1-yl유도체의 항균활성에 미치는 치환기 효과)

  • Yu, Seong-Jae;Sung, Min-Gyu;Kim, Dae-Whang;Sung, Nack-Do
    • Applied Biological Chemistry
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    • v.40 no.1
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    • pp.80-84
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    • 1997
  • Series of new chiral N-substituted benzotriazol-1-yl derivatives were synthesized and their fungicidal activities in vitro against gray mold(Botrytis cinerea), black spot(Alternaria kikuchiana) and phytophthora blight(Phytophthora capsici) were measured by the agar medium dilution method. The substituents effects between the fungicidal activities (obs. $pI_{50}$) and a various physicochemical parameters of phenoxy or thiophenoxy group(X) & alkyl or phenyl group(Y) were analyzed by the multiple regression technique. From the analyzed substituent effects, the structure-activity relationship(SAR) equations shows that the antifungal activities depend on the parameters for the optimal molecular hydrophobicity($({\Sigma}logP)_{opt}$), Van der Waals (${\Sigma}Vw$>0) volume(${\AA}^3$) and inductive constant with electron withdrawing group(${\sigma}_I$,Y>0). The activity in affected by the inductive effect (${\sigma}_I$,Y>${\sigma}_g$X) of Y-group rather than the X-group. The phenoxy substituents, 1, showed higher antifungal activity tn the thiophenoxy substituents, 2. For 1, polar substituent constant(${\sigma}^*$) was an important factor in determining the activity. And the tribromomethyl substituent, 1g showed the highest activity against the tee fungi.

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Parameter focusing on the fungicidal activity of methanesulfonamide and phenylhydrazone derivatives (Methanesulfonamide와 phenylhyazone 유도체의 살균활성에 대한 parameter focusing)

  • Sung, Nack-Do;Kim, Sun-Young;Choi, Joong-Kwon;Ok, Whan-Suk
    • The Korean Journal of Pesticide Science
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    • v.3 no.2
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    • pp.86-89
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    • 1999
  • A series of methanesulfonamide (I a- I g) and phenylhydrazone (IIa-IIh) derivatives were synthesized and their fungicidal activity in vitro against gray mold (BC: Botrytis cinerea), phytophthora blight (PC: Phytophthora capsici) and sheath blight (RS: Rhizoctonia solani) were measured by agar dilution method. The (II) deriviatives showed higher activity than ( I ) derivitives. And the relative orders of the fungicidal activity are BC=PC>RS, Among these compounds, 3-chlorophenyl substituent, IIg showed the most highest activity ($pI_{50}=3.96$) against PC. From the parameter focusing technique, major factors on the activity were ovality, polar and logP constant and so on.

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A Study of the Retention Mechanism of the Monosubstituted Benzenes in Reversed-phase Liquid Chromatography (II) (역상 액체크로마토그래피에서 벤젠 일치환체들의 머무름 메카니즘에 관한 연구 (제 2 보))

  • Lee, Dai-Woon;Choi, Yong-Wook;Lee, Won
    • Journal of the Korean Chemical Society
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    • v.32 no.2
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    • pp.135-143
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    • 1988
  • The correlations between chromatographic parameters of monosubstituted benzenes and several physical parameters in reversed phase liquid chromatography were studied. The relationships between retention data and polarity index were investigated by plotting $log(log k'_S/k'_B)$ vs. $P'_S/P'_B$ which were relative retention and relative polarity index of monosubstituted benzenes with respect to benzene, respectively. The linear relationship between relative retention and polarity index was observed for the monosubstituted benzenes having polar group, while in case of those having nonpolar group, the good linearity was observed by combination with relative molecular weight i.e. $(P'_S/P'_B)/(MW_S/MW_B)$. Multivariant regression analysis, $a(P'_S/P'_B)+b(MW_S/MW_B)$+c did not give significantly better correlations compared to single variant analysis, $a[(P'_S/P'_B)/(MW_S/MW_B)]$+c, but multiple stepwise regression analysis was recommended when several physical parameters simultaneously were chosen. The best correlation between retention data for monosubstituted benzenes taken from the literature and substituent constant(${\pi}$), derived from hydrophobic parameter and the first order molecular connectivity index$(^1{\chi}^{\nu})$, was established for methanol/water mobile phase system. The larger the surface coverage of the stationary phase, the higher was the correlation coefficient between these two parameters and retention data.

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