Compound of formula (I): wherein: represents 1-oxidopyridyl substituted by the remainder of the molecule in any one of the positions 2, 3 and 4, m and n, which may be identical or different, each represent an integer of from 1 to 3, R1 represents hydrogen or alkyl, R2 and R3, which may be identical or different, each represent an atom or group selected from hydrogen, halogen, alkyl, hydroxy, acyloxy and alkoxy, or, together with the carbon atom carrying them, form a cycloalkane having from 3 to 6 carbon atoms, R4 and R5 each represent hydrogen, or are adjacent and, together with the carbon atoms carrying them, form a benzo ring, Ar represents aryl or heteroaryl. Medicinal products containing the same which are useful as thrombin inhibitors.