3,6,9, 15-tetraaza-bicyclo [9.3.1]pentadeca-1(14), 11(15), 12-triene based compounds and their application as ligands of essential metal ion based MRI and 52MN based PET contrast agents

A compound of general formula (I)

• wherein
• Ra is —OH group;
• Rb is H-atom or alkyl group;
• X is —CH3, —COOH, —OH, —OCH3, alkoxy-, —NO2, —NH2, —NCS, —NHS-activated ester, alkyl, or aryl, wherein alkyl and aryl may be optionally substituted with hydroxyl, hydroxyalkyl, nitro, amino, or isothiocyanate group;
• and
• Y means —NH—, >N—C(O)-Q group, or >NCH2—Z group,
• where Q group is selected from:
• where R2 is a H atom, carboxyl or alkyl-carbonyl;
• where Z group is selected from:
• where z=0-18,
• where z=0-18 and R2 is H atom, alkyl, or —(CH2)n—COOH where n=1-10,
• where R2b is H atom, —CH3, —OCH3, —CF3, —COOH, —COON(CO)2(CH2)2, —NO2, —NH2, or —NCS— group,
• where z=0-18 and R2c is H atom, —NO2, —NH2, or —NCS— group,
• where z=0-18, and x=1-5,
• where z=1-5, and x=1-5, R2d is H atom, —CH3, —OCH3, —CF3, —NO2, —NH2, —NCS—COOH, or —COON(CO)2(CH2)2 group.