Imaging and radiotherapeutics agents targeting fibroblast-activation protein-α (FAP-α)

A low molecular weight compound of Formula (I):

• B-L-A (I)
• wherein:
• A is a targeting moiety for FAP-α, wherein A has the structure of:
• wherein:
• R1x and R2x are each independently selected from the group consisting of H, OH, halogen, C1-6alkyl, —O-C1-6alkyl, and —S-C1-6alkyl;
• R3x is selected from the group consisting of H, —CN, —B (OH)2—C(O) alkyl, —C(O)aryl-, —C—C—C(O) aryl, —C—C—S(O)2aryl, —CO2H, —SO3H, —SO2NH2, —PO3H2, and 5-tetrazolyl;
• R4x is H;
• R5x, R6x and R7x are H;
• v is 0;
• and
• represents a quinolinyl ring having a point of attachment to a remainder of the FAP binding moiety at the 4-position of the quinolinyl ring;
• B is any optical or radiolabeled functional group suitable for optical imaging, positron-emission tomography (PET) imaging, single-photon emission computed tomography (SPECT) imaging, or radiotherapy;
• and L is a linker having bi-functionalization adapted to form a chemical bond with B and A;
• or
• a stereoisomer, tautomer, racemate, salt, hydrate, or solvate thereof.