A compound of formula (I): ##STR1## in which: R.sub.1, R.sub.2, R.sub.3, which are identical or different, represent hydrogen, halogen, alkyl, nitro, cyano, aminosulfonyl, imidazolyl, or pyrrolyl, or alternatively, when two of them are situated on adjacent carbons, may form with the carbon atoms to which they are attached a benzene ring on C.sub.3 -C.sub.7 cyloalkyl R.sub.4 represents hydroxyl, alkoxy, phenoxy, or amino, their isomers as well as their addition salts with a pharmaceutically-acceptable base, and medicinal products containing the same which are useful as inhibitors of the the pathological phenomena linked to hyperactivation of the neurotransmission pathways by the excitatory amino acids.