Abstract: The present invention concerns the compounds of formula ##STR1## the N-oxide forms, the pharmaceutically acceptable acid addition salts and stereochemically isomeric forms thereof, wherein Alk is C.sub.1-6 alkanediyl or C.sub.3-6 alkenediyl; R.sup.1 is hydrogen or C.sub.1-4 alkyl; R.sup.2 and R.sup.3 each independently are hydrogen, C.sub.1-6 alkyl or C.sub.3-7 cycloalkyl; or R.sup.2 and R.sup.3 may also be taken together with the nitrogen atom to which they are attached, thus forming a pyrrolidine, a piperidine or a perhydro azepine ring; R.sup.

Abstract: The present invention concerns the compounds of formula ##STR1## the N-oxides, the pharmaceutically acceptable addition salts and the stereochemically isomeric forms thereof, wherein each R.sup.1 is independently hydrogen, halogen, C.sub.1-6 alkyl, nitro, hydroxy or C.sub.1-4 alkyloxy; Alk is C.sub.1-6 alkanediyl; n is 1 or 2; D is an optionally substituted mono-, bi- or tricyclic nitrogen containing heterocycle having central .alpha..sub.2 -adrenoceptor antagonist activity. It further relates to their preparation, compositions comprising them and their use as a medicine.