New urea derivatives, their preparation and their application in therapy

A urea derivative corresponding to the general formula ##STR9## in which:

• R.sup.1 represents a C.sub.1 -C.sub.4 alkyl group;
• R.sup.2 represents:
• a C.sub.5 -C.sub.7 cycloalkyl group
• a cycloalkylmethyl group in which the cycloalkyl radical contains from 5 to 7 carbon atoms
• a benzyl group
• a benzyl group in which the aromatic ring bears a C.sub.1 -C.sub.4 alkyl group, a C.sub.1 -C.sub.4 alkoxy group, a halogen atom or a nitro group;
• n represents 1 or 2;
• X represents an oxygen or sulfur atom;
• Ar represents:
• a pyridyl group
• a phenyl group of formula:
• ##STR10## where R.sub.3 and R.sub.4, independently of one another, represent a hydrogen atom, a halogen atom, a nitro goup, a C.sub.1 -C.sub.4 alkyl group, a C.sub.1 -C.sub.4 alkoxy group, a phenyl group or a trifluoromethoxy group;
• an oxofluorenyl group of formula:
• ##STR11## a dioxoanthracenyl group of formula:
• ##STR12## a naphthyl group, as well as the therapeutically acceptable organic or inorganic salts of this molecule.