Compound and photoacoustic imaging contrast medium containing the compound

A compound represented by any one of formula (1) to formula (6):

• wherein, in the formula (1), A1 represents an organic dye which absorbs light in a near-infrared wavelength region, L1 represents a linker part which is any one of —NH—, —CO—, —O—, and —S— or which contains at least one of —NH—, —CO—, —O—, and —S—, q represents an integer of 1 to 5, m and n represent independently an integer of 10 or more and 2,500 or less, and R1 and R2 represent independently an alkyl group having 1 to 5 carbon atoms,
• wherein, in the formula (2), A1 represents an organic dye which absorbs light in the near-infrared wavelength region, L1 represents a linker part which is any one of —NH—, —CO—, —O—, and —S— or which contains at least one of —NH—, —CO—, —O—, and —S—, p and q represent independently an integer of 1 to 5,1, m, and n represent independently an integer of 10 or more and 2,500 or less, and R1 and R2 represent independently an alkyl group having 1 to 5 carbon atoms,
• wherein, in the formula (3), A1 represents an organic dye which absorbs light in the near-infrared wavelength region, L1 represents a linker part which is any one of —NH—, —CO—, —O—, and —S— or which contains at least one of —NH—, —CO—, —O—, and —S—, q represents an integer of 1 to 5,1, m, and n represent independently an integer of 10 or more and 2,500 or less, and R1 and R2 represent independently an alkyl group having 1 to 5 carbon atoms,
• wherein, in the formula (4), A1 and A2 represent independently an organic dye which absorbs light in the near-infrared wavelength region, L1 and L2 represent independently a linker part which is any one of —NH—, —CO—, —O—, and —S— or which contains at least one of —NH—, —CO—, —O—, and —S—, p, q and r represent independently an integer of 1 to 5, m and n represent independently an integer of 10 or more and 2,500 or less, and R1 and R2 represent independently an alkyl group having 1 to 5 carbon atoms,
• wherein, in the formula (5), A1, A2, A3, and A4 represent independently an organic dye which absorbs light in the near-infrared wavelength region, L1, L2, L3, and L4 represent independently a linker part which is any one of —NH—, —CO—, —O—, and —S— or which contains at least one of —NH—, —CO—, —O—, and —S—, p and q represent independently an integer of 1 to 5, and n represents an integer of 10 or more and 2,500 or less, and
• wherein, in the formula (6), A1 represents an organic dye which absorbs light in the near-infrared wavelength region, L1 represents a linker part which is any one of —NH—, —CO—, —O—, and —S— or which contains at least one of —NH—, —CO—, —O—, and —S—, p and q represent independently an integer of 1 to 5, and n represents an integer of 10 or more and 2,500 or less wherein, in the formulae (1) to (6), A1, A2, A3, and A4 are independently represented by any one of formulae (7) and (8):
• wherein, in the formula (7) and in the formula (8), the symbol * represents a bond with any one of L1, L2, L3, and L4 in the formulae (1) to (6),
• wherein, in the formula (7) and in the formula (8), Z forms a cyclic aromatic ring composed of a benz[e]indole ring, benz[f]indole ring, or benz[g]indole ring together with a hydrogen atom, a sulfonate group, or an indole ring bonded to Z, and furthermore, a hydrogen atom of the cyclic aromatic ring may be substituted with an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or a sulfonate group,
• wherein, in the formula (7) and in the formula (8), R3 represents any one of an alkyl group having 1 to 10 carbon atoms and —(CH2)b—SO3− where b represents an integer of 1 to 10, and when R3 is an alkyl group, a halogen ion or an organic acid ion may be contained as a counter ion, and R4 and R5 represent independently any one of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, —(CH2)b—-SO3−, where b represents an integer of 1 to 10, and —(CH2)b—SO3X, where b represents an integer of 1 to 10 and X represents any one of sodium, potassium, ammonium, triethylammonium, lysine, and arginine,
• wherein, in the formula (7) and in the formula (8), a represents an integer of 1 to 10 and s represents 2 or 3, and
• wherein, in the formula (8), R6 represents any one of an alkyl group having 1 to 10 carbon atoms, —(CH2)b—SO3−, where b represents an integer of 1 to 10, —(CH2)b—SO3X where b represents an integer of 1 to 10 and X represents any one of sodium, potassium, ammonium, triethylammonium, lysine, and arginine.