• The Korean Journal of Pesticide Science
• /
• v.12 no.2
• /
• pp.111-117
• /
• 2008

The comparative molecular field analysis (CoMFA) for the fungicidal activity with N-phenylbenzenesulfonamide analogues (1-45) against gray mold (Botriyts cinerea) were studied quantitatively. The statistical values of CoMFA models had much better predictability and fitness than those of comparative molecular similarity indices analysis (CoMSIA) models. The statistical values of the optimized CoMFA I model were predictablity, $r^2_{cv.}(or\;q^2)=0.457$ and correlation coefficient, $r^2_{ncv.}=0.959$, and their fungicidal activity was dependent on the steric field (52%) and electrostatic field (35.6%) of the substrate molecules. And also, it was found that the optimized CoMFA I model with the sensitivity to perturbation ($d_q^{2'}/dr^2_{yy'}=0.898$) and prediction ($q^2=0.346$ & SDEP=0.614) produced by a progressive scrambling analysis was not dependent on chance correlation. From the results of graphical analyses on the contour maps with the optimized CoMFA I model, it is expected that the $R_3$ and $R_4$-substituents on the N-phenyl ring as steric favor group and para-substituents ($R_1$) on the S-phenyl ring as steric disfavor group will contribute to the fungicidal activity. Therefore, the optimized CoMFA I model should be applicable to the prediction of the fungicidal activities against gray mold.

• Korean Journal of Agricultural Science
• /
• v.35 no.1
• /
• pp.33-40
• /
• 2008

The structural characteristics that influence on the fungicidal activities of N-phenylbenzenesulfonamide (1~24) and N-phenyltheinylsulfonamide (25~30) derivatives against Dampping-off (Pythium ultimum) were discussed quantitatively using the models of molecular holographic quantitative structure-activity relationships (HQSAR). From the based on these findings, the statistical results of the optimized HQSAR F-3 model showed better predictablity ($r^2_{cv.}$ or $q^2=0.581$) and correlation coefficient ($r^2_{ncv.}=0.963$). And, from the analytical results of the atomic contribution maps on the fungicidal activities, the most active compound is $R_1=2-fluoro-4-chloro$ substituent (4) and the most inactive one is $R_1=4-methoxy$ substituent (20). It was found that the 2-fluoro-4-chlorophenyl group as a $R_1$-group was an important structure and a characteristic factor not only for herbicidal activity but also for fungicidal activity.

• The Korean Journal of Pesticide Science
• /
• v.11 no.1
• /
• pp.8-17
• /
• 2007

Three-dimensional quantitative structure-activity relationships (3D-QSARs) on the fungicidal activity against damping-off (Pythium ultimum) with N-phenylbenzenesulfonamide and N-phenyl-2-thienylsulfonamide analogues (1-34) were studied quantitatively using CoMFA (comparative molecular field analysis) and CoMSIA (comparative molecular similarity indeces analysis) methodologies. On the whole, the statistical qualities of CoMSIA models with field fit alignment (FF1-FF5) were slightly higher than that of atom based fit alignment (AF1-AF5) but, the deviations of statistical quality between two alignments in case of CoMFA models were slightly lower. The statistical results of CoMFA and CoMSIA model showed that the optimized CoMSIA model (FF1: $r_{cv.}^2\;(q^2)=0.674$ & $r_{ncv.}^2=0.964$) for damping-off is better predictability and fitness for fungicidal activities than CoMFA model (AF5: $r_{cv.}^2\;(q^2)=0.616$ & $r_{ncv.}^2=0.930$). The fungicidal activities according to the information of the CoMSIA (FF1) model were dependence upon the electrostatic and hydrophobic field of the N-phenylbenzene sulfonamide analogues. Therefore, from the results of graphical analyses on the contour maps with CoMSIA (FF3) model, it is expected that the characters of R4-substituent on the N-phenyl ring as hydrophobic and hydrogen bond acceptor will be contributed to the fungicidal activity against damping-off.

• Applied Biological Chemistry
• /
• v.50 no.3
• /
• pp.192-197
• /
• 2007

3D-QSARs on the fungicidal activity of N-phenylbenzenesulfonamide and N-phenyl-2-thienylsulfonamide analogues (1-37) against Phytophthora blight (Phytophthora capsici) were studied quantitatively using CoMFA and CoMSIA methods. The statistical results of the optimized CoMFA (2) model ($r^2_{cv.}(q^2)$ = 0.692 & $r^2_{ncv.}$= 0.965) show better predictability and fitness than CoMSIA (2) model ($r^2_{cv.}(q^2)$ = 0.796 & $r^2_{ncv.}$= 0.958). The fungicidal activities according to the information of the optimized CoMFA (2) model were dependent upon the steric and electrostatic fields of the molecules. Therefore, from the contribution contour maps of CoMFA (2) model, it is expected that 63% contribution was caused by the steric bulk of meta-substituent ($R_1$) on the S-phenyl ring. Also, the other contribution level of 32.9% was represented by the positive charged $R_4-group$ ($R_1$) on the N-phenyl ring and para-substituent ($R_1$) on the S-phenyl ring. A series of higher active compounds, $R_1$= 3-decyl substituent ($pred.pI_50$= 5.88) etc. were predicted based on the findings.