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[ 11 C]Fluoroform, a Breakthrough for Versatile Labeling of PET Radiotracer Trifluoromethyl Groups in High Molar Activity
Author(s) -
Haskali Mohammad B.,
Pike Victor W.
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201701701
Subject(s) - trifluoromethyl , chemistry , pet imaging , radiochemistry , positron emission tomography , molar ratio , specific activity , nuclear chemistry , nuclear medicine , organic chemistry , medicine , enzyme , alkyl , catalysis
Positron‐emission tomography (PET) is an immensely important imaging modality in biomedical research and drug development but must use selective radiotracers to achieve biochemical specificity. Such radiotracers are usually labeled with carbon‐11 ( t 1/2 =20 min) or fluorine‐18 ( t 1/2 =110 min), but these are only available from cyclotrons in a few simple chemical forms. [ 18 F]Fluoroform has emerged for labeling tracers in trifluoromethyl groups but is severely limited in utility by low radioactivity per mass (low molar activity). Here, the synthesis of [ 11 C]fluoroform is described, based on CoF 3 ‐mediated fluorination of cyclotron‐produced [ 11 C]methane. This process is efficient and repetitively reliable. [ 11 C]Fluoroform shows versatility for labeling small molecules in very high molar activity (>200 GBq μmol −1 ), far exceeding that possible by using [ 18 F]fluoroform. Therefore, [ 11 C]fluoroform represents a major breakthrough for labeling prospective PET tracers in trifluoromethyl groups at high molar activity.