Table 1.
1H-NMR (600 MHz) and 13C-NMR (150 MHz) spectral data of the flavone nucleus of swertisin (1) and embinoidin (2) in DMSO-d6 (δ in ppm, J in Hz).
| Position | 1 | 2 | ||
|---|---|---|---|---|
| δC | δH | δC | δH | |
| C-2 | 164.01 | ― | 163.39 | ― |
| 163.87 | ― | 163.25 | ― | |
| C-3 | 102.79 | 6.85 ( s ) | 103.78 | 6.95 ( s ) |
| 6.83 ( s ) | 103.70 | 6.93 ( s ) | ||
| C-4 | 182.21 | ― | 182.02 | ― |
| 181.88 | ― | 182.34 | ― | |
| C-5 | 159.57 | ― | 159.66 | ― |
| 160.31 | ― | 160.53 | ― | |
| C-6 | 109.65 | ― | 108.62 | ― |
| 108.67 | ― | |||
| C-7 | 164.92 | ― | 165.14 | ― |
| 163.71 | ― | 163.86 | ― | |
| C-8 | 91.00 | 6.82 ( s ) | 90.83 | 6.81 ( s ) |
| 90.16 | 6.83 ( s ) | 90.37 | 6.84 ( s ) | |
| C-9 | 156.80 | ― | 157.12 | ― |
| 156.70 | ― | 157.01 | ― | |
| C-10 | 104.07 | ― | 104.24 | ― |
| 104.58 | ― | 104.49 | ― | |
| C-1′ | 120.37 | ― | 122.69 | ― |
| C-2′, C-6′ | 128.52 | 7.96 ( d, 8.9) | 128.37 | 8.08 ( d, 8.5) |
| C-3′, C-5′ | 116.16 | 6.92 ( d, 8.9) | 114.61 | 7.13 ( d, 8.5) |
| C-4′ | 162.12 | ― | 162.41 | ― |
| 7-OMe | 56.24 | 3.87 ( s ) | 56.13 | 3.92 ( s ) |
| 56.48 | 3.96 ( s ) | 56.55 | 3.91 ( s ) | |
| 4′-OMe | ― | ― | 55.60 | 3.87 ( s) |
| 5-OH | ― | 13.52 ( s ) | ― | 13.46 ( s ) |
| ― | 13.54 ( s ) | ― | 13.58 ( s ) | |
* The small δC and δH made it difficult to associate a specific set of signals from the flavone nucleus with one of the sets of signals from the saccharide moiety.