• Korean Journal of Agricultural Science
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• v.34 no.2
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• pp.171-179
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• 2007

The new insecticidal active molecules from the based on the holographic quantitative structure-activity relationships (HQSAR) between a series of $1-(R_1)-2-(n-octyl)-3-(R_2)$, $3-(R_3)-pseudothiourea$ derivatives and their insecticidal activities against Diamond-back moth (Plutella Xylostella Linnaeus) were designed and discussed quantitatively. The most active molecule from the based graphical analyses of atomic contribution maps with the optimized HQSAR C-1 model ($q^2=0.764$ & $r^2{ncv}=0.942$) was 1-(n-butyl)-2-(t-butyl)-3,3-diisopropylpseudothiourea (P1: $pI_{50}=5.30$, $IC_{50}=1.397ppm$). Therefore, it is suggested that the new designed molecule would increased the activity as much as 23.5 times as compared to X=n-octyl substituent 17($pI_{50}=4.00$, $IC_{50}=32.86ppm$) which was the highest active molecule in training set compounds.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2749-2753
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• 2009

Structural characteristics that influence on the insecticidal activity ($pI_{50}$) of 2-(n-octyl)isothiourea analogues (1-45) against the diamondback moth (Plutella xylostella, L.) based on three dimensional quantitative structure activity relationships (3D-QSARs) were discussed quantitatively using a comparative molecular field analysis (CoMFA) and a comparative molecular similarity indeces analysis (CoMSIA) methods. The statistical values of the CoMFA 2 model were better than those of the CoMSIA 1 model. The CoMFA 2 model was the optimized model with the correlativity (the training set: Ave. = 0.104 & PRESS = 0.613) and the predictability (the test set: Ave. = 0.086 & PRESS = 0.096). Insecticidal activities with the optimized CoMFA 2 model were dependent upon steric factors (79.4%) of $R_1-R_3$ substituents. From the analytical results of CoMFA contour maps, it is predicted that the R1 substituent of 1-45 which has a steric favor in a broad space, $R_2\;and\;R_3$ groups with a steric favor in a narrow space and a H-bond donor favor would have better the insecticidal activity.