W. Wadsak, M. Mitterhauser, L. Mien
Nov 1, 2003
Citations
0
Influential Citations
11
Citations
Journal
Journal of Labelled Compounds and Radiopharmaceuticals
Abstract
Recently, two fluorine-18 labelled derivatives of flumazenil were described: 5-(2′-[18F]fluoroethyl)-5-desmethylflumazenil (ethyl 8-fluoro-5-[18F]fluoroethyl-6-oxo-5,6-dihydro-4H-benzo-[f]imidazo[1,5-a] [1,4]diazepine-3-carboxylate; [18F]FEFMZ) and 3-(2′-[18F]fluoro)-flumazenil (2′-[18F]fluoroethyl 8-fluoro-5-methyl-6-oxo-5,6-dihydro-4H-benzo-[f]imidazo[1,5-a]-[1,4]diazepine-3-carbo- xylate; [18F]FFMZ). Since the biodistribution data of the latter were superior to those of the former we developed a synthetic approach for [18F]FFMZ starting from a commercially available precursor, thereby obviating the need to prepare a precursor by ourselves. The following two-step procedure was developed: First, [18F]fluoride was reacted with 2-bromoethyl triflate using the kryptofix/acetonitrile method to yield 2-bromo-[18F]fluoroethane ([18F]BFE). In the second step, distilled [18F]BFE was reacted with the tetrabutylammonium salt of 3-desethylflumazenil (8-fluoro-5-methyl-6-oxo-5,6-dihydro-4H-benzo-[f]imidazo[1,5-a] [1,4]diazepine-3-carboxylic acid) to yield [18F]FFMZ. The synthesis of [18F]FFMZ allows for the production of up to 7 GBq of this PET-tracer, enough to serve several patients. [18F]FFMZ synthesis was completed in less than 80 min and the radiochemical purity exceeded 98%. Copyright © 2003 John Wiley & Sons, Ltd.