The present invention relates to compounds of formula (I): in which R.sup.1 and R.sup.2 independently represent phenyl, thienyl or pyridyl and R.sup.3 represents a group --X--Y--NR.sup.4R.sup.5 in which X is CO or SO.sub.2; Y is absent or represents NH and the other substituente are as defined in the description and their use in the treatment of obesity, psychiatric and neurological disorders and to pharmaceutical compositions containing them.