The invention relates to molecules ANT-ligands having a substituted nitrogeneous heterocycle A wherein A is a substituted pyrazinone of formula I wherein R1 is &mdash；(CH2)n&mdash；CO&mdash；OH； &mdash；(CH2)n&mdash；CO&mdash；OR； &mdash；(CH2)n&mdash；CO&mdash；NHR； &mdash；(CH2)n&mdash；CO&mdash；N(R,R&prime；)； &mdash；(CH2)n&mdash；OH； &mdash；(CH2)n&mdash；OR； &mdash；(CH2)n&mdash；OAr； &mdash；(CH2)n&mdash；C(R,R&prime；)&mdash；(CH2)n&mdash；OH, R and R&prime；, in the above radicals, being identical or different and representing H or a C1-C12 alkyl or cycloalkyl radical； and Ar is a phenyl or Het., Het. representing an heterocyclic radical with one or several hetero atoms selected between N, S and O, said phenyl or heterocycle being optionally substituted by one or several atoms, groups or radicals selected from halogen atoms such as Cl, Br, I, or halogenated groups such as &mdash；CCl3 or &mdash；CF3； one or several &mdash；OH, &mdash；OR, &mdash；COOH or &mdash；COOR groups； a phenyl； a linear or branched C1-C12 alkyl radical； &mdash；NH&mdash；COR； or &mdash；CN； said groups occupying the same or different positions on the phenyl or heterocyclic radical； a linear or branched C1-C12 alkyl radical； a linear or branched C2-C12 alkylene radical； &mdash；(CH2)n&mdash；C3-C6 cycloalkyl radical； &mdash；(CH2)nAr or &mdash；(CH2)nHet.； &mdash；(CH2)n&mdash；NH&mdash；CO&mdash；R； &mdash；(CH2)n&mdash；NH2； &mdash；(CH2)n&mdash；N(R,R&prime；)； &mdash；(CH2)n&mdash；NH&mdash；CO&mdash；OH； &mdash；(CH2)n&mdash；NH&mdash；CO&mdash；OR； &mdash；NH&mdash；(CH2)n&mdash；CO&mdash；OH； &mdash；NH&mdash；(CH2)n&mdash；CO&mdash；OR； R2 is &mdash；(CH2)n&mdash；Ar, Ar being such as above defined and being optionally substituted such as above defined； a linear or branched C1-C12 alkyl or C2-C12 alkylene radical with one or several double bonds； &mdash；(CH2)n&mdash；OH； &mdash；(CH2)n&mdash；OR； &mdash；(CH2)n&mdash；CO&mdash；Het； &mdash；(CH2)n&mdash；NH&mdash；CO&mdash；R； &mdash；(CH2)n&mdash；NH2； &mdash；(CH2)n&mdash；N(R,R&prime；)； &mdash；(CH2)
