Patent ID: 8367831

Claim:
A compound represented by a formula (2): wherein X 1a denotes an optionally substituted C 1 -C 3 alkylene group; Y 2 denotes an optionally protected carbonyl group; Z 1 is CR 7 , Z 2 , Z 3 , Z 4 , Z 5 and Z 6 are the same or different and are each a nitrogen atom or a group represented by a formula CR 7 , provided that at least one of Z 3 , Z 4 , Z 5 and Z 6 is a nitrogen atom, wherein R 7 denotes a hydrogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, a formyl group, an optionally protected or substituted amino group, an optionally substituted lower alkyl, cycloalkyl, aryl, lower alkoxy, cycloalkyloxy, aralkyloxy, alkanoyl, ureido or monocyclic heterocyclic group, or a group represented by a formula Q 1 CONR 8 R 9 , Q 1 CO 2 R 10 or Q 1 CN, wherein R 8 and R 9 are the same or different and are each a hydrogen atom, an optionally substituted lower alkyl, cycloalkyl, aralkyl, aryl, lower alkoxy, alkanesulfonyl or monocyclic heterocyclic group, or form, together with the nitrogen atom to which R 8 and R 9 bind, an optionally substituted cyclic amino group; R 10 denotes a hydrogen atom or a carboxyl-protecting group; and Q 1 denotes an optionally substituted lower alkylene or lower alkenylene group or a bond.