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Synthesis of [ 18 F] 4‐amino‐ N ‐(3‐chloro‐4‐fluorophenyl)‐ N′ ‐hydroxy‐1,2,5‐oxadiazole‐3‐carboximidamide (IDO5L): a novel potential PET probe for imaging of IDO1 expression
Author(s) -
Huang Xuan,
Gillies Robert J.,
Tian Haibin
Publication year - 2015
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.3263
Subject(s) - chemistry , radiosynthesis , moiety , oxadiazole , yield (engineering) , radiochemistry , chloride , chemical synthesis , fluorobenzene , aniline , stereochemistry , positron emission tomography , organic chemistry , in vitro , nuclear medicine , medicine , materials science , metallurgy , biochemistry , benzene
To synthesize 18 F‐labeled positron emission tomography (PET) ligands, reliable labeling techniques inserting 18 F into a target molecule are necessary. The 18 F‐fluorobenzene moiety has been widely utilized in the synthesis of 18 F‐labeled compounds. The present study utilized [ 18 F]‐labeled aniline as intermediate in [ 18 F]‐radiolabeling chemistry for the facile radiosynthesis of 4‐amino‐ N ‐(3‐chloro‐4‐fluorophenyl)‐ N′ ‐hydroxy‐1,2,5‐oxadiazole‐3‐carboximidamide ([ 18 F]IDO5L) as indoleamine 2,3‐dioxygenase 1 (IDO1) targeted tracer. IDO5L is a highly potent inhibitor of IDO1 with low nanomolar IC 50 . [ 18 F]IDO5L was synthesized via coupling [ 18 F]3‐chloro‐4‐fluoroaniline with carboximidamidoyl chloride as a potential PET probe for imaging IDO1 expression. Under the optimized labeling conditions, chemically and radiochemically pure (>98%) [ 18 F]IDO5L was obtained with specific radioactivity ranging from 11 to 15 GBq/µmol at the end of synthesis within ~90 min, and the decay‐corrected radiochemical yield was 18.2 ± 2.1% ( n = 4).