The invention provides novel compounds of formula (I). ##STR1## and pharmaceutically acceptable salts thereof wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 which may be the same or different, represent hydrogen, halogen, lower alkyl, and lower alkoxy, or any adjacent two of R.sub.1 to R.sub.4 taken together represent an alkylene group containing from 3 to 5 carbon atoms or a 1,4-buta-1,3-dienylene group. The compounds are useful as anti-allergic agents.
                            该发明提供了式(I)的新化合物。其中 R1、R2、R3 和 R4 可能相同或不同,表示氢、卤素、较低烷基和较低烷氧基,或者 R1 到 R4 中的任意相邻两个一起表示含有 3 到 5 个碳原子的烷基基团或 1,4-
丁二烯基团。这些化合物可用作抗过敏剂。