Arylalkyl(thio)amides

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

• ##STR21## in which :
• A represents a --CH.sub.2 --CH.sub.2 -- chain, unsubstituted or substituted with lower alkyl,
• R.sub.1 represents hydrogen or lower alkyl,
• R.sub.2 represents hydrogen, halogen, or lower alkyl,
• R.sub.3 and R.sub.4, together with the benzene ring which carries them, form a ring-system E.sub.3 chosen from :
• benzothiophene, benzofuran, and benzodioxane, on the understanding that the portion of the ring-system E.sub.3 formed by R.sub.3 and R.sub.4 and the two carbon atoms of the benzene ring which carry them is :
• unhydrogenated or partially hydrogenated,
• and unsubstituted or substituted with one or more radicals chosen from :
• halogen, hydroxyl, lower alkyl, lower alkoxy, lower alkoxycarbonyl, and trifluoromethyl,
• R.sub.5 represents hydrogen or lower alkyl,
• R.sub.6 represents a group ##STR22## in which X represents oxygen and R.sub.7 represents a radical chosen from :
• lower alkyl, unsubstituted or substituted with one or more radicals chosen from halogen, hydroxyl, and lower alkoxy,
• linear or branched alkenyl having 2 to 7 carbon atoms, inclusive, unsubstituted or substituted with one or more radicals chosen from halogen, hydroxyl, and lower alkoxy, and --(CH.sub.2).sub.m -E.sub.4 in which m represents 0 or 1 to 4, inclusive, and E.sub.4 represents a mono- or bicyclic cycloalkyl having 3 to 12 carbon atoms, inclusive, unsubstituted or substituted with one or more radicals chosen from halogen, and lower alkyl, optical isomers,
• and its addition salts thereof with a pharmaceutically-acceptable acid or base when R.sub.3 or R.sub.4 represents a salifiable group,
• on the understanding that the terms "lower alkyl" and "lower alkoxy" denote linear or branched groups having 1 to 6 carbon atoms, inclusive, and that the terms "cycloalkenyl" and "alkenyl" denote hydrocarbon groups containing one or more double bonds.