In recent years, the role of chemical mediators in asthma and other allergic diseases has been rapidly elucidated. In addition to histamine, PAF, leukotrienes, thromboxane, etc. have become known. It has been shown that leukotrienes are biosynthesized by the activity of 5-lipoxygenase from arachidonic acid, and thromboxane A.sub.2 is biosynthesized by thromboxane synthase after the catabolism with cyclooxygenase from arachidonic acid. Further, both leukotrienes and thromboxane A.sub.2 have been found to be important chemical mediators in allergic reactions, which cause various diseases such as asthma, chronic obstructive pulmonary disease, psoriasis, enteritis, nephritis, ulcers, and ischemia. Therefore, if it were possible to inhibit the biosynthesis of both chemical mediators, a greater effect could be obtained in treating or alleviating the above diseases when compared with the inhibition of single mediator.
Recently, as compounds for inhibiting the biosynthesis of such two mediators, benzothiazole derivatives (see Japanese Unexamined Patent Publication (Kokai) No. 5-178855), quinone derivatives (see Japanese Unexamined Patent Publication (Kokai) No. 5-78321), imidazolylphenol derivatives (see Japanese Unexamined Patent Publication (Kokai) No. 6-9571), and N-hydroxyurea derivatives (see WO96/23772) have become known.