3D-QSAR study of flurine-containing pesticides

The quantitative structure - activity/toxicity relationships (QSAR/QSTR) of 112 fluorine containing pesticides were studied by means of the DISCO and CoMFA method. Using the 78 compounds among them chosen randomly as a traini ng set to build up the QSAR/QSTR model, it is found that the contribution t o activity from steric effect is 60.4%, and that from electrostatic effect is 39.6%. As to the QSTR model, the contribution from steric effect is 59.2 %, and that from electrostatic effect is 40.8%. The crossvalidated R-2 are 0.652 and 0.611, and the non - crossvalidated R-2 are 0.982 and 0.977, and the values of variance ratio F are 463.6 and 362.9 for the activity and the toxicity respectively. It was proved that the two models make good predict ion for activity and toxicity, These models are also used to predict the ac tivities and toxicities of other 34 compounds in the test set. The values o f ratio of standard error and extremal length obtained, s/Delta gamma, are 10.4% and 6.4% for activity and toxicity respectively. Finally these models are improved by adding more compounds into the training set. A new molecul e dth higher activity and lower toxicity is designed using the last model.