%0 Journal Article
%A Drerup, Christian
%A Ermert, Johannes
%A Coenen, Heinrich Hubert
%T Synthesis of a Potent Aminopyridine-Based nNOS-Inhibitor by Two Recent No-Carrier-Added $^{18}$F-Labelling Methods
%J Molecules
%V 21
%N 9
%@ 1420-3049
%C Basel
%I MDPI75390
%M FZJ-2016-06731
%P 1160 -
%D 2016
%X Nitric oxide (NO), an important multifunctional signaling molecule, is produced by threeisoforms of NO-synthase (NOS) and has been associated with neurodegenerative disorders. Selectiveinhibitors of the subtypes iNOS (inducible) or nNOS (neuronal) are of great interest for decodingneurodestructive key factors, and 18F-labelled analogues would allow investigating the NOS-functionby molecular imaging with positron emission tomography. Especially, the highly selective nNOSinhibitor 6-((3-((3-fluorophenethylamino)methyl)phenoxy)methyl)-4-methylpyridin-2-amine (10)lends itself as suitable compound to be 18F-labelled in no-carrier-added (n.c.a.) form. For preparationof the 18F-labelled nNOS-Inhibitor [18F]10 a “build-up” radiosynthesis was developed based on acorresponding iodonium ylide as labelling precursor. The such activated phenethyl group of thecompound was efficiently and regioselectively labelled with n.c.a. [18F]fluoride in 79% radiochemicalyield (RCY). After conversion by reductive amination and microwave assisted displacement of theprotecting groups, the desired nNOS-inhibitor was obtained in about 15% total RCY. Alternatively,for a simplified “late-stage” 18F-labelling procedure a corresponding boronic ester precursor wassynthesized and successfully used in a newer, copper(II) mediated n.c.a. 18F-fluoro-deboroniationreaction, achieving the same total RCY. Thus, both methods proved comparatively suited to providethe highly selective NOS-inhibitor [18F]10 as probe for preclinical in vivo studies.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000385479800057
%$ 27598109
%R 10.3390/molecules21091160
%U https://juser.fz-juelich.de/record/824107