Compounds of the 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 of different, represent hydrogen, halogen, nitro, 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 are disclosed. The compounds are useful as anti-allergic agents.
式(I)的化合物:##
STR1##及其药用可接受的盐,其中R.sub.1、R.sub.2、R.sub.3和R.sub.4可能相同或不同,代表
氢、卤素、硝基、较低烷基和较低烷
氧基,或R.sub.1至R.sub.4中任意相邻的两个共同代表含有3至5个
碳原子的亚烷基基团或1,4-丁-1,3-二
烯基团。这些化合物可用作抗过敏药物。