Figure 4.
Polarization yield of hyper-SHIELDED sequence versus GPS.14 (a) Boltzmann polarized carbon-13 spectrum acquired from an aqueous solution containing 170 mmol of the reaction product. (b) Reaction schematic for synthesizing parahydrogenated 2-hydroxyethyl 1-13C-propionate-d3 (HEP). (c) Experimentally determined yields for hyper-SHIELDED and GPS comparison sequence were nearly identical and in accord with theory for the coupling arrangement in the test HEP molecule.