Compounds of formula (I): ##STR00001## wherein: R.sub.1 represents hydrogen, a halogen or alkyl, R.sub.1a represents hydrogen or alkyl, R.sub.2 represents hydrogen, a halogen or hydroxy, A represents NR.sub.4, R.sub.3 represents hydrogen, alkyl or cycloalkyl, R.sub.4 represents hydrogen or alkyl, X is as defined in the description, their isomers, and also addition salts thereof.Medicinal products containing the same which are useful in treating disorders of the AMPA system.