[11C]methyl iodide from [11C]methane and iodine using a non‐thermal plasma method

A method and an apparatus for preparing ¹¹C]methyl iodide from ¹¹C]methane and iodine in a single pass through a non‐thermal plasma reactor has been developed. The plasma was created by applying high voltage (400 V/31 kHz) to electrodes in a stream of helium gas at reduced pressure. The ¹¹C]methane used in the experiments was produced from ¹¹C]carbon dioxide via reduction with hydrogen over nickel. ¹¹C]methyl iodide was obtained with a specific radioactivity of 412 ± 32 GBq/µmol within 6 min from approximately 24 GBq of ¹¹C]carbon dioxide. The decay corrected radiochemical yield was 13 ± 3% based on ¹¹C]carbon dioxide at start of synthesis. ¹¹C]Flumazenil was synthesized via a N‐alkylation with the prepared ¹¹C]methyl iodide. Copyright © 2006 John Wiley & Sons, Ltd.