Comparison of the NMR data ( Table 1) of 1 with those see more of 2 suggested that the only difference was the presence of one additional glucopyranosyl
group in 1, and this was supported by the presence of more units of 162 in the molecular formula of 1 than that of 2. All the proton and carbon signals for compound 2 were assigned using 2D NMR spectra ( Fig. 1). Therefore, compound 2 could be established to be (20S,23R)-3β-hydroxy-12β,23-epoxy-dammar-24-ene 20-O-α-L-arabinofuranosyl-(1→6)-β-D-glucopyranoside (notoginsenoside-LY). Compound 3 was obtained as white amorphous powder. It was determined to have a molecular formula of C58H98O26 based on a [M+Na]+ ion at m/z 1233.6235 (calculated for C58H98O26Na, 1233.6244) in the HRESIMS. The IR spectrum showed absorption bands for hydroxyl (3426 cm−1) and olefinic carbons (1650 cm−1). The 1H NMR spectrum ( Table 1) showed eight methyl groups [δ 0.78 (3H, s), 0.93 (3H, s), 1.63 (3H, s), 1.61 (3H, s), 1.64 (3H, s), 1.26 (3H, s), 1.09 (3H, s), 0.94 (3H, s)], one olefinic proton [δ 5.31 (1H, m)], two oxygen substituted Cobimetinib molecular weight protons [δ 3.28 (1H, dd, J = 11.4, 4.2 Hz), 3.62 (1H, m)], and five anomeric protons [δ 4.93 (1H, d, J = 7.8 Hz), 5.52 (1H, d, J = 7.8 Hz), 5.43 (1H, d, J = 6.6 Hz), 5.14 (1H, d, J = 7.8 Hz),
5.00 (1H, d, J = 6.0 Hz)]. The 13C NMR ( Table 1) showed 58 carbon signals including a pair of olefinic carbons at C-24 (δc 125.8) and C-25 (δc 131.0). The chemical structure of 3 was further elucidated by a HMBC ( Fig. 1) experiment, in which the following correlations were observed from H-3 (δH 3.28, 1H, dd, J = 11.4, 4.2 Hz) to C-1Glc (δc 104.7); H-1Glc′ (δH 5.52, 1H, d, J = 7.8 Hz) to C-2Glc (δc 82.9); H-1xyl (δH 5.43, 1H, d, J = 6.6 Hz) to C-2Glc′ (δc 84.3); H-1Glc″ (δH 5.14, 1H, d, J = 7.8 Hz) to C-20
(δc 83.4); and H-1Ara (δH 5.00, 1H, d, J = 6.0 Hz) to C-6Glc″ (δc 69.1). The NMR data for the tetracyclic part of the aglycone and the glycosyl moieties linked to C-3 of aglycone were similar to those of notoginsenoside Fa , and glycosyl moieties linked to C-20 of aglycone were almost indistinguishable from those of ginsenoside Rb2 . The sugar moieties Cytidine deaminase of 3 were determined to be D-glucose (Glc), D-xylose (Xyl), and L-arabinose (Ara) [tR (min): 26.60, 8.86, and 6.23] by GC. The standard monosaccharides were subjected to the same reaction and GC analysis under the same condition. Retention times were consistent. Five anomeric protons were observed at δ 4.93 (1H, d, J = 7.8 Hz), 5.52 (1H, d, J = 7.8 Hz), 5.43 (1H, d, J = 6.6 Hz), 5.14 (1H, d, J = 7.8 Hz), and 5.00 (1H, d, J = 6.0 Hz).