A convenient synthesis of [11C]paraquat and other [N-methyl-11C]bisquaternary ammonium compounds

[C-11]Paraquat was synthesized by the reaction of [C-11]methyl triflate with the mono-triflate salt of 1-methyl-[4,4']bipyridinyl. The product was selectively separated from the precursor by a microcolumn of Chelex 100 ion exchange resin. The method was applied to the synthesis of a variety of [N-methyl-C-11]bisquaternary ammonium compounds. This is the first reported use of a chelating cation exchange resin for the selective purification of organic dications. Copyright (C) 2002 John Wiley Sons, Ltd.