Compounds for insecticidal control, having the formula ##STR1## in which R.sub.1 is methyl or ethyl; R.sub.2 is a straight or branched chain alkyl group having from 3 to 5 carbon atoms; R.sub.3 is hydrogen, methyl or carbomethoxy; and R.sub.4 is an alkyl group having from 1 to 4 carbon atoms, together with insecticidal compositions containing such compounds, and methods for controlling insects.