Optimizing the Reaction Conditions for the Formation of Fumarate via Trans-Hydrogenation

Abstract Parahydrogen-induced polarization is a hyperpolarization method for enhancing nuclear magnetic resonance signals by chemical reactions/interactions involving the para spin isomer of hydrogen gas. This has allowed biomolecules to be hyperpolarized such level that they can used real time in vivo metabolic imaging. One particularly promising example fumarate, which rapidly and efficiently at low cost hydrogenating an acetylene dicarboxylate precursor molecule using parahydrogen. The reaction relatively slow compared timescale on relaxes back thermal equilibrium, undesirable 2nd hydrogenation step convert fumarate into succinate. To date, chemistry not been thoroughly investigated, so previous work inconsistent chosen conditions search ever-higher rate yield. In this we investigate solution preparation protocols yield formation. We report reproducibly over 100 mM short timescale, discuss aspects protocol hinder formation or lead irreproducible results. also provide experimental procedures recommendations performing reproducible kinetics experiments gas repeatedly bubbled aqueous solution, overcoming challenges related viscosity surface tension water.