saturated ring system contains 4 to 6 carbon atoms and 1 to 3 nitrogen and atom s and the substituent may be selected from the group of carboxyl alkoxy haloalkyl nitro sulphate amino acylamino carboxylate amide monoalkylamino dialkylamino alkylthio alkylsulfinyl alkylsulfonyl and cyano where c1 3 alkyl e g methyl halogen e g fluoro or a saturated ring system containing 4 to 6 carbon and 1 to 3 n e g piperazinyl are preferred the alkyl substituent is especially preferred as used herein the term u201c aryl u201d alone or in combinations means an aromatic monocyclic or multicyclic ring system comprising 6 to 14 carbon atoms preferably 6 to about 10 carbon atoms more preferably 6 carbon atoms e g phenyl or naphthyl especially phenyl those substituted aryl groups are also within the scope which contain one or more substituent s e g 1 to 5 or 1 to 4 or 1 to 3 or 1 or 2 substituent s independently selected from each other usually applied in the organic chemistry for substitution of aryl groups so the substituted aryl groups carry one or more preferably one to three substituent s independently selected from the group of halogen optionally substituted alkyl more preferably methyl and trifluoromethyl optionally substituted alkoxy more preferably methoxy hydroxyl carboxyl carboxylate haloalkyl nitro sulphate amino amide acylamino monoalkylamino dialkylamino alkylthio alkylsulfinyl alkylsulfonyl and cyano the saturated partially unsaturated or aromatic ring systems may contain.