Benzodiazepine derivative of formula (I), and pharmaceutically acceptable salts thereof, are found to be active against RSV Formula (I) Wherein: &mdash；R1 represents C1-6 alkyl, aryl or heteroaryl； &mdash；R2 represents hydrogen or C1-6 alkyl； -each R3 is the same or different and represents halogen, hydroxy, C1-6 alkyl, C1-6 alkoxy, C1-6 alkylthio C1-6 haloalkyl, C1-6 haloalkoxy, amino, mono(C1-6 alkyl)amino, di(C1-6 alkyl)amino, nitro, cyano, &mdash；CO2R&prime；, CONR&prime；R&Prime；, &mdash；NH&mdash；CO&mdash；R&prime；, &mdash；S(O)R&prime；, &mdash；S(O)2R&prime；, &mdash；NH&mdash；S(O)2R&prime；, &mdash；S(O)NR&prime；R&Prime； or &mdash；S(O)2NR&prime；R&Prime； wherein each R&prime； and R&Prime； is the same or different and represents hydrogen or C1-6 alkyl； -n is from 0 to 3； R4 represents hydrogen or C1-6 alkyl； &mdash；R6 represents C1-6 alkyl, aryl, heteroaryl, carbocyclyl, heterocyclyl, aryl-(C1-6 alkyl)-, heteroaryl-(C1-6 alkyl)-, carbocyclyl-(C1-6 alkyl)-, heterocyclyl-(C1-6 alkyl)-, aryl-C(O)&mdash；C(O)&mdash；, heteroaryl-C(O)&mdash；C(O)&mdash；, carbocyclyl-C(O)&mdash；C(O)&mdash；, heterocyclyl-C(O)&mdash；C(O)&mdash； or, &mdash；XR6； &mdash；X represents &mdash；CO&mdash；, &mdash；S(O)&mdash； or &mdash；S(0)2&mdash；； and &mdash；R6 represents C1-6 alkyl, hydroxy, C1-6 alkoxy, C1-6 alkylthio, aryl, heteroaryl, carbocyclyl, heterocyclyl, aryl-(C1-6 alkyl)-, heteroaryl-(C1-6 alkyl)-, carbocyclyl-(C1-6 alkyl)-, heterocyclyl-(C1-6 alkyl)-, aryl-(C1-6 hydroxyalkyl)-, heteroaryl-(C1-6 hydroxyalkyl)-, carbocyclyl-(C1-6 hydroxyalkyl)-, heterocyclyl-(C1-6 hydroxyalkyl)-, aryl-(C1-6 alkyl)-O&mdash；, heteroaryl-(C1-6 alkyl)-O&mdash；, carbocyclyl-(C1-6 alkyl)-O&mdash；, heterocyclyl-(C1-6 alkyl)-O&mdash； or &mdash；NR&prime；R&Prime； wherein each R&prime； and R&Prime； is the same or different and represents hydrogen, C1-6 alkyl, carbocyclyl, heterocyclyl, aryl, heteroaryl, aryl-(C1-6 alkyl)-, heteroaryl-(C1-6 alkyl)-, carbocyclyl-(C1-6 alkyl)- or heterocyclyl-(C1-6 alkyl)-.
