Patent ID: 8053462

Claim:
A compound represented by formula (I′) or a salt thereof: wherein: X represents a bromine atom; R 1 represents a substituted or unsubstituted C 2-6 alkenyl, substituted or unsubstituted C 2-6 alkynyl, a substituted or unsubstituted aromatic group, substituted or unsubstituted aralkyl, substituted or unsubstituted arylsulfonyl, substituted or unsubstituted C 1-6 alkylsulfonyl, or hydroxyl; R 2 represents substituted or unsubstituted C 1-21 alkyl; R 3 and R 5 are the same or different and each represents a halogen atom; R 6 represents a hydrogen atom or a halogen atom; and R 4 represents a hydrogen atom or substituted or unsubstituted C 1-6 alkyl.