The compounds of the formula (I) (I) in which X denotes CH2, O, S or NR6, R1 denotes alkyl, cycloalkyl, alkenyl, (substituted) phenyl, or (substituted) naphthyl, R2 and R3 denote alkyl, alkenyl or phenyl, or R2 and R3 together denote an alkylene chain, R4 denotes -H, -CN, -CCl3, -C 3BOND CH, alkyl, F, or -C(S)-NH2, R5 denotes pyridyl, furyl, thienyl, phthalimidyl, di(C1-C4)alkylmaleinimidyl, thiophthalimidyl, dihydrophthalimidyl or tetrahydrophthalimidyl, which may all be substituted, or substituted phenyl, or R4 and R5-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 which R1 denotes phenyl which is substituted in the para-position by (C1-C4)alkoxy, halogen or (C1-C4)alkyl; R2 and R3 denote CH3; X denotes O; R4 denotes H and R5 denotes 3-phenoxyphenyl or (4-fluoro-3-phenoxy)phenyl being excepted, have advantageous insecticidal, acaricidal and nematocidal properties.