Patent ID: 7238812

Claim:
A compound represented by formula (VII) or a salt or solvate thereof: wherein R 2 and R 5 represent a hydrogen atom, and R 3 and R 4 , which may be the same or different, represent any one (a) to (d): (a) a hydrogen atom; (b) an optionally protected hydroxyl group; (c) C 1-6 alkyl which may be substituted by a halogen atom; (d) C 1-6 alkoxy which may be substituted by (1) a halogen atom, (2) a hydroxyl group, (3) cyano, (4) C 3-7 cycloalkyl, (5) phenyl, (6) C 1-4 alkoxy, (7) phenoxy, (8) amino which may be substituted by C 1-4 alkyl, (9) —COR 13 wherein R 13 represents a hydrogen atom, C 1-6 alkyl, phenyl optionally substituted by halogen or C 1-4 alkoxy, or phenyl C 1-4 alkyl, (10) —COOR 14 wherein R 14 represents a hydrogen atom or C 1-6 alkyl, (11) —CONR 15 R 16 wherein R 15 and R 16 , which may be the same or different, represent a hydrogen atom or C 1-6 alkyl which may be substituted by a saturated or unsaturated five- to seven-membered heterocyclic ring, or (12) a saturated or unsaturated five- to seven-membered heterocyclic ring which may be substituted by C 1-4 alkyl or phenyl C 1-4 alkyl; and R 52 represents a hydrogen atom or a protective group for carboxyl.