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Radiosynthesis of bromine‐76 and iodine‐123 labelled enantiomers of A‐69024: radioligands for dopamine D1 receptor studies using PET and SPECT
Author(s) -
Kassiou Michael,
Loc'h Christian,
Katsifis Andrew,
Papazian Vahan,
Mattner Filomena,
Dikic Branko,
Mazière Bernard
Publication year - 2000
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/(sici)1099-1344(20000330)43:4<339::aid-jlcr321>3.0.co;2-6
Subject(s) - chemistry , enantiomer , radiosynthesis , radioligand , high performance liquid chromatography , electrophile , bromine , biodistribution , chromatography , stereochemistry , organic chemistry , receptor , positron emission tomography , nuclear medicine , in vitro , biochemistry , medicine , catalysis
Abstract The racemic dopamine D1 receptor antagonist A‐69024 was labelled with bromine‐76 for studies using PET and with iodine‐123 for SPECT. [ 76 Br]A‐69024 was prepared via electrophilic bromodestannylation with NH 4 76 Br. The use of chloramine‐T in acid media resulted in radiochemical yields of 70–80%. The racemic radioligand was purified by semi‐preparative C‐18 reverse‐phase HPLC while the (+) and (−) enantiomers were separated and isolated using chiral HPLC. Average specific activities of 11 GBq/μmol were obtained. In an analogous manner, 2‐[ 123 I]A‐69024 was prepared via electrophilic iododestannylation with Na 123 I resulting in rediochemical yields of 65–70%. Chiral HPLC gave the (+) and (−) enantiomers with specific activities of >74 GBq/μmol. The chemical and enantiomeric purity of each enantiomer of both radioligands assessed by chiral HPLC was >98%. Radiochemical purities measured by radio‐TLC were >98%. The average time of synthesis for both preparations was 70 minutes. Copyright © 2000 John Wiley & Sons, Ltd.