| abstract |
A compound having the following formula (1) or a salt thereof: n nwherein R 1 and R 2 represent hydrogen, a lower alkyl, a lower alkenyl, a lower alkynyl or a group having the following formula (2):n n(R 6 ) n —{circle around (A)}—Z— (2),n nR 3 represents hydroxy, a lower alkoxy, a lower cycloalkyloxy, an aryloxy, carboxy, a lower alkoxycarbonyl, or —NR a R b having the following formula (3):n n(R 7 ) o —{circle around (B)}— (3),n nR 4 and R 5 represent halogen, a lower alkyl, hydroxy, or a lower alkoxy; R 6 represents halogen, a lower alkyl, an aryl group, a heterocyclic, a hydroxy, a lower alkoxy, mercapto, a lower alkylthio, a lower alkylcarbonyl, amino, nitro or cyano; R 7 represents a lower alkyl, hydroxy or a lower alkoxy; R a and R b represent hydrogen or a lower alkyl; the ring A represents a cyclic hydrocarbon or a heterocyclic ring; the ring B represents a heterocyclic ring having one or more heteroatoms selected from the group consisting of nitrogen and oxygen; X represents a lower alkylene; Y represents a lower alkylene; Z represents a single bond or a lower alkylene; W 1 -W 2 represents N—CH or C—N and l, m, n and o represent 0, 1, 2, or 3. |