¹⁵N magnetic resonance hyperpolarization via the reaction of parahydrogen with ¹⁵N-Propargylcholine

¹⁵N-Propargylcholine has been synthesized and hydrogenated with para-H ₂. Through the application of a field cycling procedure, parahydrogen spin order is transferred to the ¹⁵N resonance. Among the different isomers formed upon hydrogenation of ¹⁵N- propargylcholine, only the nontransposed derivative contributes to the observed N-15 enhanced emission signal. The parahydrogen-induced polarization factor is about 3000. The precise identification of the isomer responsible for the observed ¹⁵N enhancement has been attained through a retro-INEPT ( ¹⁵N- ¹H) experiment. T ₁ of the hyperpolarized ¹⁵N resonance has been estimated to be ca. 150 s, i.e., similar to that reported for the parent propargylcholine (144 s). Experimental results are accompanied by theoretical calculations that stress the role of scalar coupling constants (J _HN and J _HH) and of the field dependence in the formation of the observed ¹⁵N polarized signal. Insights into the good cellular uptake of the compound have been gained.