A compound of the formula:wherein Ar is an optionally substituted aromatic hydrocarbon or aromatic heterocyclic group, R is H, halogen or a group bonded through C, N, O, S or P, W is halogen or a group bonded through C, N, O, S or P, X is H or a group bonded through C, N, O or S, Y is H or a group bonded through C, N, O, S or P, or X and Y together with the adjacent nitrogen atom to Y may form an optionally substituted nitrogen-containing heterocyclic group which may further have N, O, S and/or P, or a salt thereof, a method of production thereof and agrochemicals containing the above compound [I]. The compound [I] and their salts are effective in preventing sanitary or horticultural insect pests and animal and plant parasites and can exert potent insecticidal activities when they are applied to harmed living animals or plants. Moreover, the compounds [I] and their salts possess safe and advantageous properties as agents for preventing sanitary, horticultural or agricultural injurious insects, such as no substantial damage on plants and less toxicity against fishes.