Azetidine Derivatives

A method of treatment of a disease or medical condition which benefits from inhibition of FAAH activity, wherein the disease or condition is selected from vertigo, eating disorders, acute or chronic neurodegenerative diseases, epilepsy, sleeping disorders, renal ischaemia, cancers, immune system disorders, allergic diseases, parasitic infectious diseases, viral infectious diseases, bacterial infectious diseases, osteoporosis, ocular complaints, pulmonary complaints, gastrointestinal diseases, glaucoma related hypertension and urinary incontinence, comprising administering to a subject suffering such disease or condition an effective amount of a compound of formula (I), or a pharmaceutically acceptable salt thereof:

• wherein
• Ar1 is optionally substituted phenyl or optionally substituted monocyclic heteroaryl having 5 or 6 ring atoms;
• Ar2 is optionally substituted phenyl, optionally substituted monocyclic heteroaryl having 5 or 6 ring atoms or optionally substituted fused bicyclic heteroaryl having 5 or 6 ring atoms in each fused ring;
• and
• Ar3 is a divalent radical selected from the group consisting of optionally substituted phenylene and optionally substituted monocyclic heteroarylene radicals having 5 or 6 ring atoms.