Synthesis of a Paramagnetic Myeloperoxidase Substrate with Superoxide Dismutase Activity

A scheme was constructed for synthesizing a magnetic resonance imaging (MRI) contrast agent with both myeloperoxidase (MPO) sensing and superoxide dismutase (SOD) therapeutic ability. This contrast agent was designed by modifying a previously published paramagnetic SOD mimetic with therapeutic ability to contain a substrate group for MPO. This allows the contrast agent to accumulate in sites of high MPO concentration, increasing MRI signal intensity. The scheme relies on economic dipicolinic acid as a starting material for the functionalized ligand. The reaction intended to be utilized to attach the MPO substrate is an environmentally-friendly “click chemistry” reaction. Both synthetic building blocks for the click chemistry reaction were synthesized and characterized and a new, final scheme was devised in order to increase yield and convenience.