iv includes r 3 being u2014 n r u2032 u2014 c o u2014 r 4 wherein r 4 and r u2032 are as defined above and n is 3 4 or 5 a further preferred compound of formula i c includes r 3 being u2014 c o nr u2032 r u2033 wherein r u2032 and r u2033 are as defined above an additional preferred compound of formula iv includes r 3 being 5 or 6 membered heteroaryl groups containing from 1 to 4 heteroatoms selected independently from each other from n or o which are unsubstituted or substituted by lower alkyl or cycloalkyl one further preferred compound of formula iv includes r 3 being a substituted 5 membered heteroaryl group with n being 0 1 or 2 or with n being 3 4 or 5 another preferred compound of formula i c includes r 3 being an unsubstituted 5 membered heteroaryl group with n being 0 1 or 2 or the case when n is 3 4 or 5 one more preferred compound of formula i c includes r 3 being u2014 or u2032 with r u2032 is as above and n is 0 1 or 2 or 3 4 or 5 preferred compounds of formula i in the scope of the present invention are those in which r 3 signifies 5 or 6 membered heteroaryl groups containing from 1 to 4 heteroatoms selected independently from each other from n or o which are optionally substituted by lower alkyl or cycloalkyl especially preferred are compounds of formula i wherein the heteroaryl group is selected from imidazole pyrazole 1 2 4 triazole 1 2 4 oxadiazole or tetrazole which is optionally substituted by lower alkyl or cycloalkyl 2rs 5sr 5 2 5 4 fluoro phenyl 1 toluene 4.