Radiosynthesis of the tumor hypoxia marker [18F]TFMISO via O-[18F]trifluoroethylation reveals a striking difference between trifluoroethyl tosylate and iodide in regiochemical reactivity toward oxygen nucleophiles.
Bioorg Med Chem
; 19(7): 2287-97, 2011 Apr 01.
Article
em En
| MEDLINE
| ID: mdl-21398131
ABSTRACT
The MRI hypoxia marker trifluoromisonidazole (TFMISO) [1-(2-nitro-1H-imidazol-1-yl)-3-(2,2,2-trifluoroethoxy)propan-2-ol] was successfully labeled with (18)F to expand its role into a bimodal PET/MRI probe. (18)F-Labeling was achieved via a three-step procedure in which 2,2,2-[(18)F]trifluoroethyl p-toluenesulfonate prepared by (18)F-(19)F exchange served as the [(18)F]trifluoroethylating agent. The O-[(18)F]trifluoroethylation reaction proceeded efficiently to give the intermediate 1,2-epoxy-3-(2,2,2-[(18)F]trifluoroethoxy)propane, with approximately 60% of (18)F incorporated from the tosylate precursor, which was condensed with 2-nitroimidazole to yield [(18)F]TFMISO. Approximately 40% of the [(18)F]trifluoroethyl tosylate precursor was converted into the final product. In stark contrast, 2,2,2-[(18)F]trifluoroethyl iodide failed to produce [(18)F]TFMISO, giving instead 1,1-[(18)F]difluoro-2-iodoethoxy and 1-[(18)F]fluoro-2-iodovinyloxy analogs of [(18)F]TFMISO. Thus, this investigation has identified 2,2,2-[(18)F]trifluoroethyl tosylate as an excellent [(18)F]trifluoroethylating agent, which can convert efficiently an alcohol into the corresponding [(18)F]trifluoroethyl ether.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Radioisótopos de Flúor
/
Hidrocarbonetos Fluorados
/
Misonidazol
Limite:
Humans
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article