Compounds of the general formula (I): ##STR1##

or salts thereof, which exhibit CCR5 antagonism and exert preventive and therapeutic effects against HIV infections: wherein R¹ is a 5- to 6-membered aromatic ring which bears a substituent represented by the general formula: R-Z¹-X-Z²- (wherein R¹ is hydrogen or optionally substituted hydrocarbyl; X is optionally substituted alkylene; and Z¹ and Z² are each a heteroatom) and may be further substituted, with R being optionally bonded to the aromatic ring to form another ring; Y is optionally substituted imino; and R² and R³ are each optionally substituted aliphatic hydrocarbyl or an optionally Substituted hetero-alicyclic group.