NMR experiments were performed at 14.1 T in a 5 mm BBO probe using a Bruker AVANCE console. In the experiment to obtain the 13 C polarization level, spectra were acquired of the hyperpolarized reaction mixture every 2 s using 5° flip-angle pulses. After this, a thermal equilibrium spectrum of the sample was acquired with 512 transients, using 90° flip-angle pulses separated by 90 s intervals.