Hamilton-connectivity of 3-domination critical graphs with alpha=delta+1 >= 5.

The novel acylated guanidines, ureas and substituted ureas correspond to the general formula: in which R1 repesents a substituted or unsubstituted aromatic ring, R2 represents an alkyl, aryl, or arylalkyl group, R4 repesents hydrogen or a variously substituted aryl group, X is oxygen or an imine group: NH and Y represent an alkyl aryl alkyloxy or aryloxy group or a hydrogen atom when X represents oxygen or the group COR3 with R3 representing an aromatic group, an aryloxy, aralkyloxy or alkyloxy group when X represents the NH group. They are prepared by heating an appropriate compound under reflux with an oxyaminoalcohol, in a suitable solvent. The products are useful as medicaments for the treatment of arterial hypertension, ischemica diseases of the heart and rhythmic disorders of the latter.