Imidazo - and pyrimido - 1,3,5 - thiadiazine - 4 - one

摘要

The invention relates to novel substituted imidazo- and pyrimido-1,3,5- thiadiazin-4-ones of the formula ##STR1## wherein each of R.sub.1, R.sub. 2 and R.sub.3 independently of one another is hydrogen, halogen, C.sub.1 - C.sub.4 alkyl, trifluoromethyl, C.sub.1 -C.sub.4 alkoxy, nitro, benzyl, phenyl, phenoxy, phenylthio, or phenoxy which is substituted by one or two members selected from the group consisting of halogen C.sub.1 -C.sub. 4 alkyl, trifluoromethyl, nitro, methoxy and ethoxy; each of R.sub.4, R. sub.5, R.sub.6 and R.sub.7 independently of one another is hydrogen or C. sub.1 -C.sub.4 alkyl; and n is 0 or 1, to the preparation of these novel compounds and to compositions containing them for use in pest control, especially for controlling insects and representatives of the order Acarina which are pests of plants and animals. The novel compounds are particularly effective against larval stages and nymphs of plant- destructive feeding insects, and most particularly against plant destructive cicadas, especially in rice crops.