Fig. 6. 1 H in Discovery of a stable vitamin C glycoside in crab apples (Malus sylvestris)

Fig. 6. 1 H NMR spectra of β-glucoside 2 in D O (400 MHz) demonstrating the effect of pH on proton resonances 1′-H and 4-H. Top: one drop of 2 M NaOH added to 2 NMR tube; middle: nothing added; bottom: one drop of conc. HCl added to NMR tube.