or more substituents for example f cl br i oh nh 2 sh n 3 no 2 alkyl groups such as methyl or ethyl heteroalkyl groups such as methoxy methylamino dimethylamino or cyanide wherein one or more preferably one or two of the hydrogen atoms of the aryl residue are independently of each other replaced by one or more of the above defined substituents examples are a phenyl naphthyl biphenyl 2 fluorophenyl anilinyl 3 nitrophenyl or 4 hydroxyphenyl group the term heteroaryl refers to an aryl group as defined herein wherein one two or more preferably one or two ring carbon atoms are independently of each other replaced by an oxygen nitrogen boron phosphorous or sulphur atom for example a pyridyl imidazolyl pyrazolyl quinolinyl indolyl benzimidazolyl benzoxazolyl benzisoxazolyl benzthiazolyl isoquinolinyl pyrrolyl oxazolyl isoxazolyl thiazolyl isothiazolyl 1 2 3 triazolyl 1 2 4 triazolyl oxadiazolyl thiadiazolyl indolyl indazolyl tetrazolyl pyrazinyl pyrimidinyl and pyridazinyl groups any heteroaryl group as defined herein may be substituted with one two or more substituents for example f cl br i oh nh 2 sh n 3 no 2 alkyl groups such as methyl or ethyl heteroalkyl groups such as methoxy methylamino dimethylamino or cyanide wherein one or more preferably one or two of the hydrogen atoms of the heteroaryl residue are independently of.