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Comparison of two synthetic methods to obtain [ 18 F] N‐(2‐aminoethyl)‐5‐fluoropyridine‐2‐carboxamide, a potential MAO‐B imaging tracer for PET
Author(s) -
Beer H.F.,
Haeberli M.,
Ametamey S.,
Schubiger P. A.
Publication year - 1995
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.2580361005
Subject(s) - chemistry , carboxamide , pet imaging , nucleophile , chemical synthesis , electrophile , positron emission tomography , monoamine oxidase , monoamine oxidase b , stereochemistry , nuclear medicine , enzyme , in vitro , biochemistry , medicine , catalysis
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 123 I‐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 18 F 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 18 F 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.