Patent ID: 7084149

Claim:
A compound of the formula: wherein A 1 is a pyridyl group, which may be substituted with 1) a C 1-4 alkyl group unsubstituted or substituted with a C 1-4 alkanoyl, carboxyl, or a C 1-4 alkoxy-carbonyl, 2) a C 1-3 alkoxy group, 3) C 1-6 alkanoyl, 4) C 1-4 alkylsulfonyl, 5) carbamoyl, a mono- or di-C 1-10 alkyl carbamoyl group, a mono- or di-C 6-14 arylcarbamoyl group or a mono- or di-C 7-16 aralkylcarbamoyl group, or 6) sulfamoyl, a mono- or di-C 1-10 alkyl sulfamoyl group, a mono- or di-C 6-14 arylsulfamoyl group, or a mono- or di-C 7-16 aralkyl sulfamoyl group; R 11 is a hydrogen atom, a hydrocarbon group which may be substituted; or a monocyclic aromatic heterocyclic group which may be substituted; R 21 is a hydrogen atom or a lower alkyl group which may be substituted; R 3 , R 4 , R 5 , R 6 , R 7 , R 8 and R 9 are independently a hydrogen atom, a hydrocarbon group which may be substituted, a hydroxy group which may be substituted, a thiol group which may be substituted, an amino group which may be substituted, an acyl group or a halogen atom, provided (1) that R 7 is a hydroxy group which may be substituted or a lower alkyl group when A 1 is a pyridyl group and one of R 11 or R 21 is a hydrogen atom and (2) that R 21 is a lower alkyl group which may be substituted when R 11 is a hydrogen atom, or a salt thereof.