New iodination reactions for the synthesis of SPECT imaging agents

This thesis describes the development of a mild, one-pot, diazotisation-iodination reaction, via a stable diazonium salt intermediate. The reaction is tolerant of various functional groups and substitution patterns, and was used as the final step in the synthesis of six potential or currently used radiotracers for SPECT imaging. The transformation was also adapted for use with sodium [125I]iodide as a mild, operationally simple method to access 125I-labelled SPECT radiotracers. The full radiosynthesis of the imaging agent iomazenil is described with iodine-125 and iodine-123. This one-pot reaction was then utilised for the development of new SPECT imaging agents for the N-methyl-D-aspartate (NMDA) receptor. A small library of analogues based on the SPECT imaging agent CNS1261 were synthesised. The final project describes the development of a metal-catalysed iodination reaction from non-halide starting materials. The use of a highly active ruthenium catalyst and a nonaflate leaving group gave promising results for a number of substrates.