• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1469-1473
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• 2010

Influences of alrylamino (R) substituents on the herbicidal activity ($pI_{50}$) of 1-(4-chloro-2-fluoro-5-propargyloxypheny)-3-(R)-thiourea analogues (1 ~ 35) against the barnyard grass (Echinochloa crusgalli) in the pre-emergence step were discussed quantitatively using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) as the three dimensional quantitative structure-activity relationship (3D-QSAR) method. The statistically most satisfactory CoMFA models for the herbicidal activity against the barnyard grass had the better predictability ($r^2{_{cv.}}$) and correlativity ($r^2{_{ncv.}}$) than those of CoMSIA models. The optimized CoMFA model 1($r^2{_{cv.}}$ = 0.531 & $r^2{_{ncv.}}$ = 0.931) with the sensitivity to the perturbation (${d_q}^{2'}{dr^2}_{yy'}$ = 1.081) and the prediction ($q^2$ = 0.475) produced by a progressive scrambling analyses were not dependent on chance correlation. And statistical qualities with the atom based fit alignment (AF) were slightly higher than those of the field fit alignment (FF). According to the optimized CoMFA model 1, the contribution ratio (%) of the steric field (76.9%) on the herbicidal activity of the Thioureas was three-fold higher than that of the electrostatic field (20.1%) and the hydrophobic field (3.0%) had the least influence. A steric favor group is on the vicinity of the nitrogen atom in alrylamino (R) substituent, and a steric disfavor group is on the outer side of alrylamino (R) substituent. Thus, as the size of alrylamino (R) substituent increases, so does the herbicidal activity of the substituent.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.2
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• pp.109-115
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• 2008

The comparative molecular field analyses(CoMFA) models between the substituents with changing groups($R_1{\sim}R_4$) of $3{\beta}$-hydroxy-12-oleanen-28-oic acid derivatives as substrate molecule and their inhibitory activities($pI_{50}$) against protein tyrosine phosphatase(PTP)-1B were derived and discussed quantitatively. The optimized CoMFA F1 model have best predictability and fitness($r^2_{cv.}=0.654$ and $r^2_{ncv.}=0.995$). The order of contribution ratio (%) with CoMFA fields on the inhibitory activities was a steric field(53.0%), electrostatic field(36.2%) and hydrophobic field(10.8%). From the analytical results of CoMFA contour maps, the inhibitory activities were dependent on the R4 group in substrate molecules. Particularly, the new active compounds(P1 & P2) with the inhibitory activity against melanin synthesis were expected.

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.613-617
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• 2009

3D-QSARs for the inhibition activities against protox by herbicidal 2-N-phenylisoindolin-1-one derivatives were studied quantitatively using CoMFA and CoMSIA methods. The result of the statistical quality of optimized CoMSIA model 2 ($FF:\;{r^2}_{cv.};\;0.973\;&\;{r^2}_{ncv.};\;0.612$) was higher than that of CoMFA model 1 ($AF:\;{r^2}_{cv.};\;0.414\;&\;{r^2}_{ncv.};\;0.909$). Also, the relative contribution of the optimized CoMSIA model 2 showed the steric (24.6%), electrostatic (31.0%), hydrophobic (ClogP, 23.4%) and H-bond acceptor field (21.0%), respectively. From the results of the contour maps, the protox inhibition activities are expected to increase when steric favor and H-bond acceptor favor groups are substituted on $R_2$ position and positive favor group are substituted on $C_2,\;C_3,\;and\;C_5$ atom in phenyl ring of $R_2$ position. And the inhibition activities are expected to increase when hydrophobic favor group is substituted on $C_1,\;C_3$ atom in phenyl ring of $R_2$ position and $C_1$ atom of $R_2$ position and hydrophilic favor groups are substituted on $C_4$ atom in phenyl ring of $R_1$ position and the terminal group of $R_1$ position.

• The Korean Journal of Pesticide Science
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• v.9 no.1
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• pp.26-34
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• 2005

3D-QSAR studies for the fungicidal activities against resistance phytophthora blight (RPC; 95CC7303) and sensitive phytophthora blight (Phytopthora capsici) (SPC; 95CC7105) by a series of new 2-alkoxyphenyl-3-phenylthioisoindoline-1-one derivatives (A & B) were studieded using comparative molecular similarity indices analyses (CoMSIA) methodology. From the based on the results, the two CoMSIA models, R5 and S1: as the best models were derivated. The statistical results of the models showed the best predictability and fitness for the fungicidal activities based on the cross- validated value ($q^2=0.714{\sim}0.823$) and non cross-validated, value ($r^2_{ncv.}=0.918{\sim}0.954$), respectively. The model R5 for fungicidal activity of RPC generated from the field fit alignment and combination of electrostatic field, H-bond acceptor field and LUMO molecular orbital field. The model S1 (or S5) for fungicidal activity of SPC generated from the atom based fit alignment and combination of steric field and HOMO molecular orbital field. The models also shows that inclusion of H-bond acceptor field (A) improved the statistical significance of the models. From the based graphical analyses of CoMSIA contribution maps, it was revealed that the novel selective character for fungicidal activities between the two fungi by modify of X-sub-stituent on the N-phenyl group and R-substituent on the S-phenyl group will be able to achivement.