Novel insecticides of the formula ##STR1## in which R is a hydrogen atom or a lower alkyl group,X is a halogen atom, a lower alkyl group, a lower alkoxy group, a lower alkylthio-group, a lower alkylsulfinyl group, a lower alkylsulfonyl group, a lower alkenyl group, a lower alkynyl group, an aryl group, an aryloxy group which may be optionally substituted by a halogen atom, an arylthio group which may be optionally substituted by a halogen atom, or an aralkyl group,l is 1, 2, 3 or 4,m is 2, 3, or 4, andn is 0, 1, 2 or 3,or salts thereof. Intermediates therefor of the formula ##STR2## are also new.