QUANTITATIVE STRUCTURE-ACTIVITY-RELATIONSHIPS IN ACARICIDAL 4H-1,3,4-OXADIAZIN-5(6H)-ONES

A series of 37 2,4-diphenyl-1,3,4-oxadiazin-5-one acaricides has been synthesized. Their acaricidal activity has been related to certain of their physicochemical properties by using a Hansch-type regression equation. The initial equation developed was validated by predicting the activity of an additional nine compounds which were subsequently synthesized and tested. The QSAR study was carried out to optimize activity, resulting in a 6-fold increase in activity over the lead compound. Two novel aspects of the study were (i) the use of a new technique for selecting the compounds in the original set, so as to maximize the information obtained for a given amount of synthesis effort, and (ii) the use of a statistical technique called censored data regression to make use of information from compounds that were insufficiently acaricidal to allow determination of an ED50.