Patent ID: 8461142

Claim:
A compound of formula I or II: or a pharmaceutically acceptable salt thereof, wherein the compound contains at least one group having a negative charge at physiological pH, wherein M represents 2H or a metal atom selected from divalent Pd, Pt, Co, Sn, Ni, Cu, Zn and Mn, and trivalent Fe, Mn and Cr; R 1 and R 4 each independently is Y—R 5 ; Y is O, S or NR 5 R 6 ; R 2 is —OCH 3 ; R 3 is selected from —CH═CH 2 , —C(═O)—CH 3 , —C(═O)—H, —CH═NR 7 , —C(CH 3 )═NR 7 , —CH 2 —OR 7 , —CH 2 —SR 7 , —CH 2 —NR 7 R′ 7 , —CH(CH 3 )—OR 7 , —CH(CH 3 )—SR 7 , —CH(CH 3 )—NR 7 R′ 7 , —CH(CH 3 )Hal, —CH 2 -Hal, —CH 2 —R 7 , —CH═CR 7 CR 7 R′ 7 , —C(CH 3 )═CR 7 R′ 7 , —CH═CR 7 Hal, —C(CH 3 )═CR 7 Hal, and —C≡CR 7 ; R 5 , R 6 , R 7 and R′ 7 each independently is H or selected from the group consisting of: (a) C 1 -C 25 hydrocarbyl optionally containing one or more heteroatoms, phenyl moieties, or pyridyl moieties, each heteroatom individually selected from O, S, and N, wherein the C 1 -C 25 hydrocarbyl is unsubstituted or substituted by one or more functional groups selected from the group consisting of halogen, oxo, OH, SH, CHO, NH 2 , CONH 2 , COOH, COSH, SO 3 H, and PO 3 H 2 ; (b) a residue of an amino acid, a peptide or of a protein; and (c) when Y is O or S, R 5 may further be R 8 + ; m is 0 or 1; and R 8 + is H + or a cation; provided that: (i) at least one of R 5 , R 6 , R 7 and R′ 7 is a C 1 -C 25 hydrocarbyl substituted by a group selected from COOH, COSH, SO 3 H, and PO 3 H 2 ; or (ii) at least one of R 1 , R 2 , and R 4 is OH, SH, O − R 8 + or S − R 8 + ; excluding compounds of formula I and pharmaceutically acceptable salts thereof when R 1 is OH; and excluding compounds of formula II and pharmaceutically acceptable salts thereof devoid of a central metal atom and having a —CH 2 CH 2 COOH group at position 17, a —CH 2 COOH or —COOH group at position 15, a —COOH group at position 13, methyl groups at positions 2, 7, 12, and 18, and ethyl groups at positions 3 and 8.