Folate-conjugates and corresponding metal-chelate complexes for use in diagnostic imaging and radiotherapy

A compound of formula I

• wherein
• F is a folate or derivative thereof,
• Z1, Z2, Z3 are independently of each other C or N,
• S1, S2, S3 are independently of each other a single bond or a spacer, such as straight chain or branched C1-C12 alkyl, which is unsubstituted or substituted by at least one —CN, -Hal, —OH, —NH2, —SH, —SO3H or —NO2, and wherein one or more of the non-adjacent CH2 groups may independently be replaced by —O—, —CO—, —CO—O—, —O—CO—, —NR′—, —N═, —NR′—CO—, —CO—NR′—, —NR′—CO—O—, —O—CO—NR′—, —NR′—CO—NR′—, —CH═CH—, —C C—, —S—, —SO3R′—, —PR′— or a five- or six-membered aromatic carbocyclic or heterocyclic ring, which is unsubstituted or substituted with —CN, -Hal, —NO2, —COR′ or —COOR′, wherein R′ represents H or C1-C6 alkyl,
• Ra, Ra′, Rb are independently of each other H, —OR′, —COOR′, —NHR′, —CONHR′, —SR′, a phosphine or a heterocyclic group, wherein R′ represents H or C1-C6 alkyl, or a F as defined hereinabove, and wherein of groups Ra, Ra′ and Rb at least two adjacent groups are a donor group —OH, —COOH, —NHR′, —CONH2, —SH, a phosphine or a heterocyclic group
• Rc is H, CO2R′, COR′, —SO3R′, —NHR′, wherein R′ represents H, C1-C6 alkyl, or straight-chain or branched C1-C12 alkyl, which is unsubstituted or substituted by at least one CN, Hal, or NO2, or a F as defined hereinabove,
• m is 0, 1, 2, 3, or 4, and
• n is 1 or 2.