Comparison of two synthetic methods to obtain [18F] N-(2-aminoethyl)-5-fluoropyridine-2-carboxamide, a potential MAO-B imaging tracer for PET
作者:H.-F. Beer、M. Haeberli、S. Ametamey、P. A. Schubiger
DOI:10.1002/jlcr.2580361005
日期:1995.10
The compound Ro 19-6327, N-(2-aminoethyl)-5-chloropyridine-2-carboxamide, is known to inhibit reversibly and site specifically the enzyme monoamine oxidase B (MAO-B). The 123I-labelled iodo-analogue N-(2-aminoethyl)-5-iodopyridine-2-carboxamide (Ro 43-0463) was investigated successfully in human volunteers by means of SPET (Single Photon Emission Tomography). We developed therefore the synthesis and radiolabelling of the corresponding fluoro-analogue N-(2-aminoethyl)-5-fluoropyridine-2-carboxamide with 18F in order to carry out PET (Positron Emission Tomography) investigations of MAO-B related neuropsychiatric diseases. For this purpose two synthetic approaches leading to the electrophilic and the nucleophilic methods of 18F radiolabelling were undertaken. The nucleophilic approach appeared to be superior when factors such as precursor synthesis, beam time, specific activity and radiochemical purity of the product are considered.
化合物Ro 19-6327,即N-(2-氨基乙基)-5-氯吡啶-2-甲酰胺,已知能可逆且特异性地抑制单胺氧化酶B(MAO-B)。其123I标记的碘类似物N-(2-氨基乙基)-5-碘吡啶-2-甲酰胺(Ro 43-0463)已成功通过单光子发射断层扫描(SPET)在人体志愿者中进行了研究。因此,我们开发了相应的氟类似物N-(2-氨基乙基)-5-氟吡啶-2-甲酰胺与18F的合成及放射性标记,以进行正电子发射断层扫描(PET)研究与MAO-B相关的神经精神疾病。为此,我们采取了两种合成途径以实现18F放射性标记的亲电法和亲核法。当考虑到前体合成、束流时间、比活度和放射化学纯度等因素时,亲核法显示出优势。