Alpha, alpha-dialkylbenzyl derivatives

The invention concerns alpha , alpha -dialkylbenzyl derivatives of the formula I wherein Ar is phenyl or naphthyl, or a 10-membered bicyclic heterocyclic moiety containing one or two nitrogen heteroatoms and optionally containing a further heteroatom selected from nitrogen, oxygen and sulphur; A is a direct link to X or is (1-3C)alkylene; X is oxy, thio, sulphinyl or sulphonyl; the phenylene group may optionally bear one or two substituents R ; each of R and R , which may be the same or different, is (1-4C)alkyl, (2-4C)alkenyl, (2-4C)alkynyl, fluoro-(1-4C)alkyl, phenyl or phenyl-(1-4C)alkyl, provided that both of R and R are not methyl or fluoromethyl; and Q is cyano, amino, nitro, formyl, (1-4C)alkoxy, thiazolyl or (2-4C)alkanoyl; or a pharmaceutically-acceptable salt thereof; processes for their manufacture; pharmaceutical compositions containing them and their use as 5-lipoxygenase inhibitors.