RESUMO
The present paper is concerned with radiochemical methodology to furnish the trifluoromethyl motif labelled with (18)F. Literature spanning the last four decades is comprehensively reviewed and radiochemical yields and specific activities are discussed.
Assuntos
Compostos de Flúor/síntese química , Radioisótopos de Flúor/química , Radioquímica/métodos , Compostos Radiofarmacêuticos/síntese química , Compostos de Flúor/química , Compostos Radiofarmacêuticos/químicaRESUMO
This report is concerned with an efficient, Cu(I)-mediated method for the radiosynthesis of [(18)F]trifluoromethyl arenes, abundant motifs in small molecule drug candidates and potential radiotracers for positron emission tomography. Three (18)F-labelled radiotracer candidates were synthesised from [(18)F]fluoride ions as proof of principle. The new protocol is widely applicable for the synthesis of novel radiotracers in high radiochemical yields.
Assuntos
Radioisótopos de Flúor/química , Marcação por Isótopo/métodos , Compostos Radiofarmacêuticos/síntese química , Catálise , Cobre/química , Fluoretos/química , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos/farmacologiaRESUMO
Radiolabelling of cocaine-derived 3-phenyltropanes for dopamine transporter positron emission tomography with (18) F and (11) C is reviewed.
Assuntos
Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Compostos Radiofarmacêuticos/síntese química , Tropanos/síntese química , Animais , Radioisótopos de Carbono/química , Radioisótopos de Flúor/química , Humanos , Marcação por Isótopo , LigantesRESUMO
Recent reports have claimed a superior performance of HEPES buffer in comparison to alternative buffer systems for (67/68) Ga labeling in aqueous media. In this paper we report spectroscopic ((1) H and (71) Ga NMR), radiochemical, mass spectrometry and theoretical modeling studies on the Ga(3+)/HEPES system (HEPES = N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) performed with the aim of elucidating a potential contribution of HEPES in the (68/67) Ga radiolabeling process. Our results demonstrate that HEPES acts as a weakly but competitive chelator of Ga(3+) and that this interaction depends on the relative Ga(3+): HEPES concentration. A by-product formed in the labeling mixture has been identified as a [(68) Ga]Ga(HEPES) complex via chromatographic comparison with the nonradioactive analog. The formation of this complex was verified to compete with [(68) Ga]Ga(NOTA) complexation at low NOTA concentration. Putative chelation of Ga(3+) by the hydroxyl and adjacent ring nitrogen of HEPES is proposed on the basis of (1)H NMR shifts induced by Ga(3+) and theoretical modeling studies.
