Compounds represented by the general formula: <;CHEM>; Äwherein R<;1>; represents methoxy, ethyl, methylthio, etc., R<;2>;, R<;3>; and R<;4>; each represent hydrogen, a halogen, etc., R<;5>; and R<;6>; each represent -X<;5>;-X<;6>;-X<;7>; (wherein X<;5>; represents a single bond or -CO-, X<;6>; represents a single bond, -NR<;3a>;, etc. and X<;7>; and R<;3a>; each represent hydrogen, C1-10 alkyl, etc.), and Ar represents phenyl, pyridyl, etc.Ü, salts thereof and hydrates of the foregoing.