Health & Environmental Research Online (HERO)


Print Feedback Export to File
858570 
Journal Article 
No-carrier-added 11C-labelling of benzenoid compounds in ring positions by condensation of nitro-[11C]methane with pyrylium salts 
Mäding, P; Steinbach, J; Johannsen, B 
2000 
Yes 
Journal of Labelled Compounds and Radiopharmaceuticals
ISSN: 0362-4803
EISSN: 1099-1344 
43 
6 
565-583 
English 
WOS:000087034500004 
A new synthesis is described for three no-carrier-added nitro-[1-11C]benzenes 3a–c by condensation of nitro[11C]methane (1) with the appropriate pyrylium salts 2a–c in the presence of a base such as t-BuOK in t-BuOH. For synthesizing 4-nitro-[4-11C]anisole (3a), tetrabutylammonium fluoride was successfully used as an auxiliary base. The best results were obtained in the synthesis of 3a. The conversion of 1 with 4-methoxypyrylium perchlorate (2a) yielded 3a of a radiochemical purity of up to 82 % and a mean specific radioactivity of 30 GBq/μmol (0.8 Ci/μmol) within 20 min. Related to 1, the reproducible radiochemical yields of 3a are in the range of 77±5 % (decay-corrected). 2,6-Dimethyl-4-methoxy-nitro-[1-11C]benzene (3b) was prepared by reaction of 1 with 2,6-dimethyl-4-methoxy-pyrylium perchlorate (2b) in radiochemical yields of about 37 % (decay-corrected) within 10 min. 2-Nitro-[2-11C]mesitylene (3c) was obtained by condensation of 1 with 2,4,6-trimethylpyrylium tetrafluoroborate (2c) in radiochemical yields of about 29 % (decay-corrected) within 20 min. 13C/11C Co-labelling experiments were carried out in order to confirm the identity of 3a–c and the position of the label. 
C-11-ring labelling; nitro-[C-11]methane; 4-nitro-[4-C-11]anisole; 2,6-di-methyl-4-methoxy-nitro-[1-C-11]benzene; 2-nitro-[2-C-11]mesitylene