Compounds of formula ##STR1## where A is an alkylene chain of 1 or 2 carbon atoms optionally substituted by one or more lower alkyl groups, R is hydrogen or lower alkyl, R.sup.1 is an aryl or heteroaryl radical, R.sup.2 is a mono- or bicyclic heterocyclic radical, R.sup.3 is hydrogen, lower alkyl or hydroxy and R.sup.4 is a aryl or heteroaryl radical, and their pharmaceutically acceptable acid addition salts are 5-HT.sub.1A binding agents which may be used, for example, for the treatment of CNS--disorders such as anxiety.