This invention is concerned with compounds of the formula ##STR00001## wherein X, A, B, R.sup.1, R.sup.2 and G are as defined in the description and claims, and pharmaceutically acceptable salts thereof. The invention further relates to pharmaceutical compositions containing such compounds, to a process for their preparation and to their use for the treatment and/or prevention of diseases which are associated with the modulation of SST receptors subtype 5.