2.8. 1H NMR and 13C NMR
30 mg of the sample were analyzed by 1H and 13C NMR spectra were recorded using a Varian 500 MHz NMR spectrometer in methanol-D4 solutions (Budryn et al., 2009 and Hernandez et al., 2009). Chemical shifts were read relative to the internal standard (TMS).