Imidazonaphthyridines and their use in inducing cytokine biosynthesis

A compound of the formula I, or a pharmaceutically acceptable salt thereof, wherein: A is =N-CR=CR-CR=; =CR-N=CR-CR=; =CR-CR=N-CR=; or =CR-CR=CR-N=; R1 is selected from the group consisting of hydrogen, alkyl or alkenyl that is unsubstituted or substituted by one or more substituents selected from the group consisting of aryl, heteroaryl, heterocyclyl, alkyl,-O-(alkyl)0-1-aryl, -O-(alkyl)0-1-heteroaryl, -O-(alkyl)0-1-heterocyclyl, alkoxycarbonyl, -S(O)0-2-alkyl, -S(O)0-2-(alkyl)0-1-aryl, -S(O)0-2(alkyl)0-1-heteroaryl, -S(O)0-2-(alkyl)0-1-heterocyclyl, -N(R3)2, -N3, oxo, halogen, -NO2, -OH and -SH; alkyl-NR3-Q-X-R4 or alkenyl-NR3-Q-X-R4; Q is-CO-or SO2-; X is a bond, -O- or -NR3-; R4 is aryl; heteroaryl; heterocyclyl; or alkyl or alkenyl that is unsubstituted or substituted by one or more substituents selected from the group consisting of aryl, heteroaryl, heterocyclyl, O-alkyl, -O-(alkyl)0-1-aryl, -O-(alkyl)0-1-heteroaryl, -O-(alkyl)0-1-heterocyclyl, -alkoxycarbonyl, -S(O)0-2-alkyl, -S(O)0-2-(alkyl)0-1-aryl, -S(O)0-2-(alkyl)0-1-heteroaryl, -S(O)0-2-(alkyl)0-1-heterocyclyl, -N(R3)2; -NR3-CO-O-alkyl, -N3, oxo, halogen, -NO2, -OH, and -SH; or R4 is a group of formula (Ia) wherein Y is -N-or -CR-; R2 is selected from the group consisting of -hydrogen; -alkyl; -alkenyl; -aryl; -alkyl-O-alkyl; -alkyl-O-alkenyl; and -alkyl or alkenyl substituted by one or more substituents selected from the group consisting of -OH, -halogen, -N(R3)2, -CO-N(R3)2, -CO-alkyl, -N3, -aryl, -heteroaryl, -heterocyclyl, -CO-aryl and -CO-heteroaryl; each R3 is independently selected from the group consisting of hydrogen and alkyl; and each R is independently selected from the group consisting of hydrogen, alkyl, alkoxy, halogen and trifluoromethyl. A compound of the formula II or a pharmaceutically acceptable salt thereof, wherein B is -NR-C(R)2-C(R)2-C(R)2-, -C(R)2-NR-C(R)2-(R)2-, -C(R)2-C(R)2-NR-C(R)2- or -C(R)2-C(R)2-C(R)2-NR- and R and R1 are as defined in formula (I). A compound of formula (III) or a pharmaceutically acceptable salt thereof, wherein A is -N=CR-CR=CR-, -CR=N-CR=CR-, -CR=CR-N=CR- or -CR=CR-CR=N-, and R and R1 are as defined in formula (I). Compounds of formulae (XXXIII) and (XXXIV) or pharmaceutically acceptable salts thereof, wherein R and R1 are as defined in formula (I). A compound of formula (IV) or a pharmaceutically acceptable salt, wherein A is =N-CR=CR-CR=, =CR-N=CR-CR=, =CR-CR=N-CR=, or =CR-CR=CR-N=, R7 is OH, halogen, or NHR1, R and R1 are as defined in formu