the invention relates to compounds of the general formula wherein r 1 , r 2 , r 3 , r 4 , r 5 , r 6 , r 7 , r 8 , and x are as defined in the description , or pharmaceutically acceptable salts , hydrates , geometrical isomers , racemates , tautomers , optical isomers , n - oxides and prodrug forms thereof . the compounds may be used for the treatment or prophylaxis of disorders related to the mch1r receptor and for modulation of appetite . the invention also relates to such use as well as to pharmaceutical formulations comprising a compound of formula .