• Applied Biological Chemistry
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• v.48 no.4
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• pp.394-399
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• 2005

The comparative molecular field analyses (CoMFA) models for the herbicidal activities against barnyardgrass (Echinochloa crus-galli) and rice plant (Orysa sativa L.) by the substituent (R) on the hexahydroisoindol-1-one ring in a series of new 2-(4-chloro-5-(2-chloroallyloxy)-2-fluorophenyl)-3-thioalkoxy-2,3,4,5,6,7-hexahydroisoindol-1-one derivatives were conducted and discussed for selectivity between both plants. The statistical results of the two best models (B2 & R7) showed the best predictability for the herbicidal activities based on the cross-validated value $q_2(r^2cv.=0.529{\sim}0.755)$ and none cross-validated value $({r^2}_{ncv.}=0.937{\sim}0.945)$, respectively. Based on the findings, the predictability and fitness of the model (B2) for barnyard grass was better than that of the model (R7) for rice plant. From the two models and contour maps, it is revealed that the novel selective character for herbicidal activity between the two plants depend on the electrostatic field and steric field for the substituent of ortho-positions on the S-phenyl group as R-substituent in hexahydroisoindol-1-one ring.

• The Korean Journal of Pesticide Science
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• v.9 no.3
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• pp.199-204
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• 2005

The herbicidal activities against barnyardgrass (Echinochloa crus-galli) by R-groups on the hexahydroisoindol-1-one ring of new 2-(4-chloro-5-(2-chloroallyloxy)-2-fluorophenyl) -3-thioalkoxy-2,3,4,5,6,7-hexahydroisoindol-1-one derivatives were studied using molecular holographic quantitative structure-activity relationships (HQSAR) methodology. Based on the results, the statistical results of the optimised HQSAR model (I-2) exhibited the best predictability and fitness for the herbicidal activities based on the cross-validated value ($r^2_{cv.}$ or $q^2=0.714$) and non-cross-validated value ($r^2_{ncv.}=0.922$), respectively. From the based graphical analyses of atomic contribution maps, herbicidal activities against barnyardgrass were confirmed depends upon the C4-C6 atoms of hexahydroisoindoline-l-one ring, carbon atom of ortho-position and meta-methyl group of 3-tolylthio substituent (8).