Contrast agent containing silsesquioxane

A contrast agent containing:

• (A) a silsesquioxane represented by General Formula (I),
• wherein R1 is a substituent represented by General Formula (IIB),
• wherein p represents an integer of from 1 to 5, q is the same or different, and represents an integer of from 1 to 5, r is the same or different, and represents an integer of from 2 to 10, and R2 is hydrogen atom;
• and
• (B) a paramagnetic metal ion.

A contrast agent containing:

• (A) a silsesquioxane represented by General Formula (I),
• wherein R1 is a substituent represented by General Formula (IIC),
• wherein p represents an integer of from 1 to 5, q is the same or different, and represents an integer of from 1 to 5, r is the same or different, and represents an integer of from 2 to 10, and R2 is hydrogen atom;
• and
• (B) a paramagnetic metal ion.

A process for producing a silsesquioxane represented by General Formula (I2),

• wherein R12, the same or different, is a substituent bonded to Si through a carbon atom, the substituent having, at its terminal, a group represented by General Formula (II2),
• wherein p is an integer of from 1 to 5, and q is the same or different, and is an integer of from 1 to 5,
• or a group represented by General Formula (III2),
• wherein p and q are the same as above,
• the process comprising the steps of:
• (1) reacting an amino compound or its salt represented by General Formula (IV),
• wherein R3, the same or different, is a substituent bonded to Si through a carbon atom, the substituent having —(CH2)p—NH2, wherein p is the same as above, at its terminal,
• with an ester compound represented by General Formula (V),
• wherein R4 represents alkyl group, aralkyl group or acyl group, X represents Cl, Br or I, and q is the same as above,
• thereby obtaining a silsesquioxane represented by General Formula (I1),
• wherein R11 is the same or different, and is a substituent having, at its terminal,
• wherein p, q and R4 are the same as above;
• and
• (2) converting the R4 of the silsesquioxane (I1) obtained in Step (1) into a hydrogen atom.

A process for producing a silsesquioxane represented by General Formula (IB2),

• wherein p is an integer of from 1 to 5, q is the same or different, and is an integer of from 1 to 5, r is the same or different, and is an integer of from 2 to 10, and RIB2 is the same or different,
• the process comprising the steps of:
• (1) reacting an amino compound or its salt represented by General Formula (IVA),
• wherein R3A is the same or different, and represents —(CH2)p—NH2, wherein p is the same as above,
• with an ester compound represented by General Formula (VB1),
• wherein R4B1 represents alkyl group, aralkyl group or acyl group, XB1 represents Cl, Br or I, and q is the same as above,
• thereby obtaining a silsesquioxane represented by General Formula (IB1),
• wherein p, q and R4B are the same as above;
• (2) reacting the silsesquioxane (IB1) obtained in Step (1) with a diamine compound represented by General Formula (VIB),
• wherein r is the same as above,
• thereby obtaining an amide compound represented by General Formula (IVB),
• wherein p, q and r are the same as above, and R3B is the same or different;
• (3) reacting the amide compound obtained in Step (2) with an ester compound represented by General Formula (VB2),
• wherein R4B2 represents alkyl group, aralkyl group or acyl group, XB2 represents Cl, Br or I, and q is the same as above,
• thereby obtaining a silsesquioxane represented by General Formula (IB1′)
• wherein p, q, and R4B2 are the same as above, and RIB1′ is the same or different;
• and
• (4) converting the R4B2 of the silsesquioxane (IB1′) obtained in Step (3) into a hydrogen atom.

A process for producing a silsesquioxane represented by General Formula (IC2),

• wherein p is an integer of from 1 to 5, q is the same or different, and is an integer of from 1 to 5, and r is the same or different, and is an integer of from 2 to 10, and RIc2 is the same or different,
• the process comprising the steps of:
• (1) reacting a silsesquioxane represented by General Formula (IB1′)
• wherein p, q, and r are the same as above, and R4B2 represents alkylgroup, aralkyl group or acyl group, and RIB1 is the same or different;
• with a diamine compound represented by General Formula (VIC),
• wherein r is the same as above,
• thereby obtaining an amide compound represented by General Formula (IVC),
• wherein p, q and r are the same as above, R3C is the same or different;
• (2) reacting the amide compound obtained in Step (1) with an ester compound represented by General Formula (VC),
• wherein XC represents Cl, Br or I, R4C represents alkyl group, aralkyl group or acyl group, and q is the same as above,
• thereby obtaining a silsesquioxane represented by General Formula (IC 1),
• wherein p, q, r and R4C are the same as above, and RIc1 is the same or different;
• and
• (3) converting the R4C of the silsesquioxane (IC1) obtained in Step (2) into a hydrogen atom.