*3.4. High-Pressure Liquid Chromatography (HPLC)*

The liquid samples were analyzed by HPLC (Waters, Alliance separation module e2695) with RI detector (Waters, 2414 module) and a Rezex ROA-Organic Acid H+ (8%) column. As mobile phase, 25 mM H2SO4 was used at 0.5 mL/min of flow rate. The temperatures of the column and the detector were 40 and 30 ◦C.

#### *3.5. Nuclear Magnetic Resonance Spectroscopy (NMR Spectroscopy)*

Spectra of all the samples in which SB-13C was used as carbon source were recorded on a 500 MHz Agilent instrument equipped with a OneNMR probe. The acquisition parameters for 13C NMR spectra were as follows: 25 ◦C, 70 s relaxation delay between transients, 45◦ pulse width, spectral width of 31250 Hz, a total of 16 transients and 1.048 s acquisition time. The inverse gated decoupling technique to suppress the nuclear Overhauser effect (NOE) was used to obtain quantitative measurement. The acquisition parameters for 1H NMR spectra were as follows: 25 ◦C, 70 s relaxation delay between transients, 90◦ pulse width, spectral width of 8012.8 Hz, a total of 4 transients and 2.044 s acquisition time. The sequence PRESAT was used in order to suppress the strong signal of water.

1H and 13C NMR chemical shifts (δ) were reported in parts per million (ppm) and referenced to tetramethylsilane (TMS).
