Table 3 NMR spectroscopic data for the oligosaccharide moieties of the triterpene glycosides (recorded in methanol-d4; δ in ppm; J in Hz). Assignments aided by HMQC and HMBC experiments. mult., multiplicity.
Position | TPG1 | TPG2 | TPG3 | TPG4 | TPG5 | |||||
|---|---|---|---|---|---|---|---|---|---|---|
δ C | δH mult. (J)c | δ C | δH mult. (J) | δ C | δH mult. (J) | δ C | δH mult. (J)b | δ C | δH mult. (J)b | |
α-L-Ara (C-3) | ||||||||||
1 | 105.2, | 4.47 m | 105.0 | 4.49 dd (5.0, 1.5) | 104.4 | 4.56 dd (5.0, 1.5) | 106.3 | 4.31 d (7.6) | 106.3 | 4.31 d (7.6) |
2 | 76.7 | 3.64 m | 76.9 | 3.65 m | 76.9 | 3.71 m | 72.9 | 3.71 m | 72.9 | 3.72 d (11.5) |
3 | 74.1 | 3.64 m | 74.0 | 3.65 m | 74.0 | 3.71 m | 74.6 | 3.54 m | 74.6 | 3.53 dd (9.6, 3.4) |
4 | 69.9 | 3.76 m | 69.8 | 3.76 m | 69.8 | 3.77 m | 70.1 | 3.85 dt (3.5, 1.6) | 70.1 | 3.84 dt (3.3, 1.5) |
5 | 66.0 | 3.84 m;3.52 dd (12.4, 1.9) | 65.7 | 3.84 dd (12.3, 3.9); 3.51 dd (12.3, 2.2) | 65.7 | 3.84 dd (12.0, 5.0); 3.50 dd (11.6, 2.2) | 67.8 | 3.93 dd (12.7, 2.1); 3.65 dd (12.8, 1.3) | 67.8 | 3.93 dd (12.7, 2.1); 3.65 d (12.4) |
α-L-Rha | ||||||||||
1 | 101.6 | 5.19 d (1.8) | 101.7 | 5.17 d (1.9) | 101.9 | 5.16 d (1.7) | ||||
2 | 70.9 | 4.25 dd (3.2, 1.8) | 71.1 | 4.24 dd (3.2, 1.9) | 71.1 | 3.91 dd (3.5, 1.7) | ||||
3 | 82.9 | 3.87 dd (9.5, 3.1) | 82.8 | 3.88 dd (9.5, 3.0) | 82.8 | 3.48 d (11.2) | ||||
4 | 72.4 | 3.56 m | 72.3 | 3.56 t (9.5) | 72.3 | 3.37 q (9.5) | ||||
5 | 70.0 | 3.93 dq (9.6, 6.2) | 70.1 | 3.92 dq (9.7, 6.2) | 70.1 | 3.85 q (6.2) | ||||
6 | 17.8 | 1.27 d (6.0) | 18.1 | 1.26 d (6.2) | 18.1 | 1.24 d (6.3) | ||||
β-D-Glc | ||||||||||
1 | 105.7 | 4.52 d (7.8) | 105.8 | 4.51 d (7.8) | ||||||
2 | 75.44 | 3.36 m | 75.3 | 3.31 dd (7.9, 1.32) | ||||||
3 | 76.6 | 3.39 m | 77.8 | 3.38 t (8.9) | ||||||
4 | 73.7 | 3.42 d (9.5) | 71.3 | 3.33 d (11.2) | ||||||
5 | 76.3 | 3.48 t (9.0) | 77.8 | 3.57 d (11.3) | ||||||
6 | 61.6 | 3.82 m; 3.67 dd (12.0, 3.7) | 62.4 | 3.87 dd (11.9, 2.4); 3.86 dd (12.3, 3.9) | ||||||
α-L-Rha (terminal) | ||||||||||
1 | 102.8 | 4.85 d (1.7) | ||||||||
2 | 72.1 | 3.64 m | ||||||||
3 | 79.0 | 3.59 m | ||||||||
4 | 72.39 | 3.84 m | ||||||||
5 | 70.6 | 3.99 dq (9.5, 6.2) | ||||||||
6 | 18.2 | 1.26 d (6.0) | ||||||||
β-D-Glc (C-28) | ||||||||||
1 | 95.7 | 5.37 d (8.1) | ||||||||
2 | 73.9 | 3.33 m | ||||||||
3 | 78.2 | 3.35 d (8.5) | ||||||||
4 | 71.1 | 3.39 m | ||||||||
5 | 78.5 | 3.42 m | ||||||||
6 | 62.5 | 3.80 m; 3.71 m | ||||||||
