Abstract: The present invention relates to the compound of formula (I), in which R1 represents Sn(R)3, B(OH)2, B(OR)2, a halogen atom, NO2, a radionuclide or a —N+(R)3 group, where R is a (C1-C6) alkyl group, R2 represents a hydrogen atom or a (C1-C6)alkyl group, R3 represents: a —(CH2CH2O)n2—(CH2)n3—X group, or a —(CH2CH2O)n4—(CH2)n5—Y group with Y representing a —C?C—H, a —N3 or a —Ar—(CH2)n6—(OCH2CH2)n7—X group, and X represents a halogen atom, a radionuclide or a —OSO2R? group, where R? is a CF3, CH3, t-Bu, Ph, p-NO2Ph, p-BrPh or p-CH3Ph group, and their addition salts with pharmaceutically acceptable acids, The present invention also relates to pharmaceutical compositions comprising them and to their use in diagnosis, in particular with SPECT or PET imaging and in therapy of melanoma, via targeted radionuclide therapy.