Table 1.
1H (400 MHz) and 13C (100 MHz) NMR spectroscopic data of 2–4 (CDCl3, δ in ppm, J in Hz)a
| Position | 2 | 3 | 4 | |||
|---|---|---|---|---|---|---|
| δH | δC | δH | δC | δH | δC | |
| 1 | 6.50 s | 104.4 | 6.39 s | 103.9 | - | 140.2 |
| 2 | - | 152.0 | - | 150.3 | - | 140.2 |
| 3 | - | 136.4 | - | 134.5 | 6.15 s | 107.6 |
| 4 | - | 147.2 | - | 146.8 | - | 161.5 |
| 4a | - | 114.9 | - | 114.7 | - | 124.2 |
| 4b | - | 121.1 | - | 107.8 | - | 117.4 |
| 5 | - | 141.7 | 8.02 s | 111.5 | - | 156.6 |
| 6 | -- | 147.6 | -- | 147.2 | 6.93 d (2.0) | 108.9 |
| 7 | 6.74 d (8.0) | 109.2 | 147.1 | - | 161.0 | |
| 8 | 6.79 d (8.0) | 119.1 | 6.79 s | 111.1 | 6.82 d (2.0) | 102.0 |
| 8a | - | 132.6 | - | 125.4 | - | 129.0 |
| 9 | 2.64 s | 30.6 | 2.74 s | 29.5 | 8.06 d (8.4) | 137.7 |
| 10 | 2.64 s | 31.8 | 2.74 s | 30.9 | 8.12 d (8.4) | 122.9 |
| 10a | - | 136.4 | - | 130.1 | - | 132.7 |
| OMe-2 | 3.89 s | 56.3 | 3.88 s | 56.2 | - | - |
| OMe-3 | 3.86 s | 61.0 | 3.89 s | 61.3 | - | - |
| OMe-4 | - | - | - | - | 3.96 s | 57.2 |
| OMe-6 | 3.85 s | 56.1 | 3.92 s | 56.0 | - | - |
| OMe-7 | - | - | 3.92 s | 56.1 | 3.90 s | 55.7 |
a
Assignments confirmed by APT, gHMQC, gCOSY and gHMBC experiments