ANT-ligands having a substituted nitrogeneous heterocycle A whereinA is a substituted pyrimidinone of formula IwhereinR1 is —(CH2)n-CO—OH—(CH2)n-CO—OR—(CH2)n-CO—NHR—(CH2)n-CO—N(R, R′)—(CH2)n-OH—(CH2)n-OR—(CH2)n-OAr—(CH2)n-C(R,R′)—(CH2)n-OH,R and R′, 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 —CCl3 or —CF3 one or several —OH, —OR, —COOH or —COOR groups a phenyl a linear or branched C1-C12 alkyl radical —NH—COR or —CN said groups occupying the same or different positions on the phenyl or heterocyclic radical a linear or branched C1-C12 alkyl radicala linear or branched C2-C12 alkylene radical—(CH2)n-C3-C6 cycloalkyl radical—(CH2)n Ar or —(CH2)n-Het.—(CH2)n-NH—CO—R—(CH2)nNH2 —(CH2)n-N(R,R′)—(CH2)n-NH—CO—OH—(CH2)n-NH—CO—OR—NH—(CH2)n-CO—OH—NH—(CH2)n-CO—ORR2 is —(CH2)n-Ar, Ar being such as above defined and being optionally substituted such as above defineda linear or branched C1-C12 alkyl or C2-C12 alkenyl radical,—(CH2)n-OH—(CH2)n-OR—(CH2)n-CO-Het—(CH2)n-NH—CO—R—(CH2)n-NH2—(CH2)n-N(R,R′)—(CH2)n-CO—OH—(CH2)n-CO—ORa linear or branched C1-C12 alkyl radical—(CH2)n-C(R)═CH—C(R)═CH2R3 forms a phenyl or an heterocyclic condensed group with the two adjacent carbons of the pyrazinone residue, said condensed group being optionally substituted such as above defined for Ar and Het. and/or condensed to a cyclohexyl or oxanyl group, in turn optionally substituted such as above defined for Arn is 0 or an integer from 1 to 5 orA is a substituted pyrimidine of formula IIwhereinR4 is a —CO—NH—Ar radical, optionally substituted such as above definedR5 forms a phenyl or heterocyclic gr
