Compounds of the general formula I ##STR1## wherein R.sup.1 is hydrogen or a methoxy, ethoxy, propoxy, butoxy, tetrafluoroethoxy, methylthio, ethylthio, propylthio, fluoro, chloro, bromo, methyl, ethyl, or nitro group, and R.sup.2 is hydrogen or a methyl group, or R.sup.1 and R.sup.2 together form a methylenedioxy group;R.sup.3 is hydrogen, or a lower alkyl group, or one of the following groups (a) to (f):(a) 3-phenoxybenzyl(b) 2-benzyl-4-furylmethyl(c) .alpha.-cyano-3-phenoxybenzyl(d) 3,4-methylenedioxybenzyl(e) .alpha.-ethynyl-3-phenoxybenzyl(f) .alpha.-cyano-3-(4'-chlorophenoxy)-benzyland Y.sup.1, Y.sup.2, Y.sup.3, Y.sup.4, Y.sup.5 and Y.sup.6 are the same or different groups and each is hydrogen or a fluoro, bromo or chloro group, with the proviso that when R.sup.1 is hydrogen, fluoro, chloro, bromo or methyl and R.sup.2 is hydrogen, then one of Y.sup.1 to Y.sup.6 is other than hydrogen.The compounds in which R.sup.3 is one of groups (a) to (f) are insecticides.