The invention concerns an aniline derivative of formula (I) wherein R includes hydrogen and (1-4C)alkyl; R includes hydrogen and (1-4C)alkyl; R is hydrogen or (1-4C)alkyl; X includes a group of the formula CR R wherein R is hydrogen or (1-4C)alkyl and R is hydrogen or (1-4C)alkyl; A includes a direct link to X ; X includes thio and sulphonyl; Ar includes phenylene, which may be optionally substituted; R includes hydrogen and (1-4C)alkyl; and R and R together form a ring having 5 to 6 ring atoms including one oxygen atom, and which ring may bear one, two or three substituents, including methyl alpha to the oxygen atom; or a pharmaceutically acceptable salt thereof; processes for their preparation; pharmaceutical compositions containing them and their use as 5-lipoxygenase inhibitors.