Compounds of formula (I): ##STR00001## wherein: R.sup.1 represents a (C.sub.3-C.sub.8)cycloalkyl group, R.sup.2 represents a group of formula (II) as defined in the description, X represents an oxygen atom or an N--OR' group wherein R' represents a hydrogen atom, a linear or branched (C.sub.1-C.sub.6)alkyl group, an aryl group or an aryl-(C.sub.1-C.sub.6)alkyl group in which the alkyl moiety may be linear or branched. Medicinal products containing the same which are useful as hypoglycaemic and hypolipaemic agents.