The compounds of the formula (I) ##STR1## in which X denotes CH.sub.2, O, S or NR.sup.6,R.sup.1 denotes alkyl, cycloalkyl, alkenyl, (substituted) phenyl, or (substituted) naphthyl,R.sup.2 and R.sup.3 denote alkyl, alkenyl or phenyl, or R.sup.2 and R.sup.3 together denote an alkylene chain,R.sup.4 denotes --H, --CN, --CCl.sub.3, --C.tbd.CH, alkyl, F, or --C(S)--NH.sub.2,R.sup.5 denotes pyridyl, furyl, thienyl, phthalimidyl, di(C.sub.1 -C.sub.4)alkylmaleinimidyl, thiophthalimidyl, dihydrophthalimidyl or tetrahydrophthalimidyl, which may all be substituted, or substituted phenyl, orR.sup.4 and R.sup.5 --together with the carbon atom bridging them--denote an optionally substituted indanyl, cyclopentenoyl or cyclopentenyl radical,with the proviso that compounds of the formula I in whichR.sup.1 denotes phenyl which is substituted in the para-position by (C.sub.1 -C.sub.4)alkoxy, halogen or (C.sub.1 -C.sub.4)alkyl;R.sup.2 and R.sup.3 denote CH.sub.3 ;X denotes O;R.sup.4 denotes H andR.sup.5 denotes 3-phenoxyphenyl or (4-fluoro-3-phenoxy)phenyl being excepted,have advantageous insecticidal, acaricidal and nematocidal properties.