005AK - Mini-Reviews in Organic Chemistry, 2007, 4, 317-329...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Mini-Reviews in Organic Chemistry, 2007, 4, 317-329 317 1570-193X/07 $50.00+.00 © 2007 Bentham Science Publishers Ltd. Recent Developments and Trends in 18 F-Radiochemistry: Syntheses and Applications Ralf Schirrmacher 1* , Carmen Wängler 2 and Esther Schirrmacher 3 1 Montreal Neurological Institute, McGill University, Montreal, Canada 2 Department of Radiopharmaceutical Chemistry, German Cancer Research Center, Heidelberg, Germany 3 Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montreal, Canada Abstract : In this short review we describe recent methods and novel trends for the introduction of fluorine-18 into molecules which in turn are intended to serve as imaging agents for the in vivo imaging modality positron emission tomography (PET). These 18 F-labeling schemes are based on enzymatic fluorination, the use of ionic liquids, protic solvents acting as catalysts, application of “click chemistry”, thiol-reactive labeling agents for peptide and protein labeling and the most recent introduction of “non-classical” radiochemistry based on organo-phosphorous, organo-boron and organo-silicon radiochemistry. The latter approach for the first time introduced an 18 F-chemistry characterized by high selectivity and unique efficiency making complicated work-up procedures obsolete. Keywords: Fluorine-18, positron emission tomography (PET), labeling chemistry. 1. INTRODUCTION Due to the high dissemination of positron emission tomography (PET) [1], an imaging modality investigating the distribution of radiolabeled biomarkers in vivo (humans and animals), the syntheses of radiolabeled biologically active compounds such as peptides, neuro-transmitter ligands and enzyme targets with the positron emitting radio- halide fluorine-18 has gained widespread interest in life science [2]. Fluorine-18 can be considered to be among the “ideal” positron emitters for PET because of its physical characteristics: a half-life of 110 min to conduct scans over several hours and a low positron energy allowing for images of highest resolution. The labeling methods for the introduction of 18 F into complex organic molecules such as peptides or proteins so far described are most often characterized by multi-step synthetic pathways, synthesizing small 18 F-labeled molecules (prosthetic groups) which have to be prepared in advance by complicated procedures before final conjugation to the bio-marker of interest [3]. Due to the very restricted chemistry of 18 F which is determined by the production method of 18 F ( via irradiation of specific targets e.g. [ 18 O]water with protons or neon-20 with deuterons) [4] yielding either anionic 18 F - or carrier (non radioactive [ 19 F]fluorine gas) added [ 18 F]F 2 , the general synthesis of those 18 F-prosthetic groups is very limited in terms of chemistry. In the case of anionic 18 F - , the syntheses of these precursor compounds, mainly 18 F-labeled alkylating agents, amines, aldehydes and acid chlorides involve nucleophilic substitutions using suitable leaving groups [5]. A most recent achievement
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/17/2011 for the course CHEMISTRY 101 taught by Professor Csr during the Spring '11 term at University of Louisville.

Page1 / 13

005AK - Mini-Reviews in Organic Chemistry, 2007, 4, 317-329...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online