A compound of the formula (I): R1-A-X-NHCO???Y???R2 wherein R1 is phenyl, R2 is phenyl which have trihalo(lower)alkyl, A is a group of the formula: in which R3 and R4 are linked together to form imino, R5 is hydrogen, p is 1, n is 0, X is phenylene which have halogen and lower alkoxy, Y is vinylene, and a salt thereof. 4.