Base-substituted debenz�b,f!oxepines of formula I ##STR1## wherein alk is a divalent aliphatic radical, R is an amino group that is unsubstituted or mono- or di-substituted by monovalent aliphatic and/or araliphatic radicals or disubstituted by divalent aliphatic radicals, and R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each, independently of the others, hydrogen, lower alkyl, lower alkoxy, halogen or trifluoromethyl, and pharmaceutically acceptable salts thereof, may be used as anti-neurodegenerative active ingredients of medicaments. The invention relates also to novel compounds of formula I.