A compound of formula wherein R 1 is hydrogen, C 1-7 -alkyl, C 1-7 -alkoxy, halogen, S-C 1-7 -alkyl, C 1-7 -alkoxy substituted by halogen, di-C 1-7 -alkyl amino, C O-C 1-7 -alkyl, C 1-7 -alkyl substituted by hydroxy or hydroxy; R 2 is hydrogen, C 1-7 -alkyl, halogen, C 1-7 -alkoxy, S-C 1-7 -alkyl, C 1-7 -alkoxy substituted by halogen, O(CH 2) 2 -C 1-7 -alkoxy substituted by halogen, di-C 1-7 -alkyl amino, C 1-7 -alkyl amino, NH-C 1-7 -alkyl substituted by halogen, N(C 1-7 -alkyl)-benzyl, C 1-7 -alkyl substituted by hydroxy, heterocycloalkyl optionally substituted by halogen, CH 2 -C 1-7 -alkoxy, CH2-C 1-7 -alkoxy substituted by halogen or hydroxy; or R 1 and R 2 form together with the carbon atoms to which they are attached a ring containing -OCH 2 CH 2 O-, OCH 2 O-, OCH 2 CH 2 CH 2 O- or -NHC CH 2 O-; R 3 is hydrogen or C 1-7 -alkoxy; R 4 is hydrogen or C 1-7 -alkyl; R 5 is C 1-7 -alkyl, cycloalkyl, C 1-7 -alkyl substituted by hydroxy or C 1-7 -alkyl substituted by halogen; or R 4 and R 5 form together with the nitrogen atom to which they are attached a ring containing -CH 2 CH 2 CHRCH 2 CH 2 -, -CH 2 CHRCH 2 CH 2 -, -CH 2 CH 2 OCH 2 CH 2 -, -CH 2 CH 2 NR'CH 2 CH 2 -, CH 2 CHR- or -CH 2 CH 2 CH 2 -; wherein R is hydrogen, halogen, C 1-7 -alkyl, C 1-7 -alkoxy or C 1-7 -alkyl substituted by halogen; R' is C 1-7 -alkyl substituted by halogen; R a is hydrogen or 3 H; R b is hydrogen, hydroxy or 3 H; R 6 is hydrogen, halogen or C 1-7 -alkyl; HetAr is selected from the group consisting of thiophenyl, furanyl, thiozolyl, benzofuranyl, pyrazolyl, benzoimidazolyl or pyridinyl; n is 1 or 2; or a pharmaceutically acceptable acid addition salt, a racemic mixture or its corresponding enantiomer and/or optical isomers thereof. R 1 is hydrogen, C 1-7 -alkyl, C 1-7 -alkoxy, halogen, S-C 1-7 -alkyl, C 1-7 -alkoxy substituted by halogen, di-C 1-7 -alkyl amino, C O-C 1-7 -alkyl, C 1-7 -alkyl substituted by hydroxy or hydroxy; R 2 is hydrogen, C 1-7 -alkyl, halogen, C 1-7 -alkoxy, S-C 1-7 -alkyl, C 1-7 -alkoxy substituted by halogen, O(CH 2) 2 -C 1-7 -alkoxy substituted by halogen, di-C 1-7 -alkyl amino, C 1-7 -alkyl amino, NH-C 1-7 -alkyl substituted by halogen, N(C 1-7 -alkyl)-benzyl, C 1-7 -alkyl substituted by hydroxy, heterocycloalkyl optionally substituted by halogen, CH 2 -C 1-7 -alkoxy, CH2-C 1-7 -alkoxy substituted by halogen or hydroxy; or R 1 and R 2 form together with the carbon atoms to which they are attached a ring containing -OCH 2 CH 2 O-, OCH 2 O-, OCH 2 CH 2 CH 2 O- or -NHC CH 2 O-; R 3 is hydrogen or C 1-7 -alkoxy; R 4 is hydrogen or C 1-7 -alkyl; R 5 is C 1-7 -alkyl, cycloalkyl, C 1-7 -alkyl substituted by hydroxy or C 1-7 -alkyl substituted by halogen; or R 4 and R 5 form together with the nitrogen atom to which they are attached a ring containing -CH 2 CH 2 CHRCH 2 CH 2 -, -CH 2 CHRCH 2 CH 2 -, -CH 2 CH 2 OCH 2 CH 2 -, -CH 2 CH 2 NR'CH 2 CH 2 -, CH 2 CHR- or -CH 2 CH 2 CH 2 -; wherein R is hydrogen, halogen, C 1-7 -alkyl, C 1-7 -alkoxy or C 1-7 -alkyl substituted by halogen; R' is C 1-7 -alkyl substituted by halogen; R a is hydrogen or 3 H; R b is hydrogen, hydroxy or 3 H; R 6 is hydrogen, halogen or C 1-7 -alkyl; HetAr is selected from the group consisting of thiophenyl, furanyl, thiozolyl, benzofuranyl, pyrazolyl, benzoimidazolyl or pyridinyl; n is 1 or 2;