The chemical compounds of the invention are useful as the active compound in drugs because of their anticonvulsant and/or antianoxic activity. They have the general formula ##STR1## wherein Z is a hydroxyl group; a group--OM wherein M is an alkali metal atom or an equivalent atom fraction of an alkaline-earth metal or an amino group such as --NH.sub.2, and R is a linear or branched alkyl group containing from 1 to 9 carbon atoms, and optionally substituted by one or more halogen atoms; a linear or branched alkenyl or alkynyl, alkoxyalkyl, or acylalkyl group containing from 2 to 9 carbon atoms and optionally substituted by one or more halogen atoms; an aryl or arylalkyl or aryloxyalkyl group comprising at least one aromatic radical and an alkyl chain having from 1 to 4 carbon atoms.