A compound selected from those of formula (I): ##STR00001## wherein: R.sub.1 represents an NR.sub.3SO.sub.2R.sub.4 group wherein: R.sub.3 represents a hydrogen atom or an alkyl group, R.sub.4 represents an alkyl group, aryl group or NR.sub.5R.sub.6 group, R.sub.2 represents an alkyl, cycloalkyl or cycloalkylalkyl group, and medicinal products containing the same which are useful in treating conditions treatable by antagonists of type H.sub.3 central histamine receptors.