Aminoalkyl benzoxazolinones and benzothiazolinones

A compound which is selected from those of formula (I):

• ##STR16## in which:
• R.sub.1 represents hydrogen or alkyl,
• n represents 1 or 2,
• X represents oxygen or sulfur,
• R.sub.2 represents hydrogen or alkyl,
• and R.sub.3 represents the group --(CH.sub.2).sub.m --R.sub.4 in which:
• m represents 1,2, 3 or 4,
• and R.sub.4 represents a heterocyclic radical of formula:
• ##STR17## wherein s is four (4), which is unsubstituted or substituted with a radical selected from aryl, arylalkyl, substituted aryl, and substituted arylalkyl,
• or alternatively, when X represents sulfur R.sub.2 forms, with R.sub.3 and the nitrogen atom which bears them, a group:
• ##STR18## wherein s is four (4), wherein the substituent R.sub.5 is chosen from aryl, arylalkyl, substituted aryl, and substituted arylalkyl,
• the term "substituted", used in reference to the "aryl" and "arylalkyl" radicals, meaning that these groups are substituted with one or more groups chosen from halogen, alkyl, hydroxyl, alkoxy, and trifluoromethyl,
• the terms "alkyl" and "alkoxy" denote linear or branched groups containing 1 to 6 carbon atoms inclusive,
• the term "aryl" represents a phenyl or naphthyl group,
• the term "cycloalkyl" denotes a group of 3 to 9 carbon atoms inclusive,
• the optical isomers thereof and the addition salts thereof with a pharmaceutically-acceptable acid and, when R.sub.1 represents a hydrogen atom, with a pharmaceutically-acceptable base.