Table 1.
1H-NMR (300 MHz) and 13C-NMR (75 MHz) data of compounds 14, 15, and 16; measured at 300 K; solvent: CDCl3 (δ in ppm, J in Hz)
| 14 | 15 | 16 | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Position | δH | δC | HMBC | δH | δC | HMBC | δH | δC | HMBC |
| 1 | – | 133.5 | – | – | 132.1 | – | – | 130.3 | – |
| 2 | 6.62 (s) | 101.8 | C-3, 4, 6, 7 | 6.51 (s) | 103.4 | C-7, 3, 4, 6 | – | 142.9 | – |
| 3 | – | 147.1 | – | – | 146.8 | – | – | 137.2 | – |
| 4 (16 : 3a) | – | 133.9 | – | – | 133.8 | – | – | 144.6 | – |
| 5 (16 : 5a) | – | 147. 1 | – | – | 146.8 | – | – | 125.9 | – |
| 6 | 6.62 (s) | 101.8 | C-2, 4, 5, 7 | 6.51 (s) | 103.4 | C-7, 2, 4, 5 | 7.05 (s) | 114.3 | C-1, 2, 3a, 5, 5a |
| 7 | 5.07 (dd, 8.8, 4.1) | 69.6 | C-2, 6, 9 | 3.54 (d, 8.8) | 48.1 | C-2, 6, 8, 9 | 3.10 (m) 3.21 (m) |
26.3 | C-1, 2, 6, 8, 9 |
| 8 | 2.73 (dd, 8.8, 4.1) | 43.0 | C-1, 7, 9 | 3.43 (d, 8.8) | 44.1 | C-1, 7 | 2.65 (m) 2.77 (m) |
34.5 | C-1, 7, 9 |
| 9 | – | 172.7 | – | – | 172.8 | – | – | 174.2 | – |
| 16 : 4 | – | – | – | – | – | – | 7.58 (d, 2.1) | 145.3 | C-3a, 5, 5a |
| 16 : 5 | – | – | – | – | – | – | 6.68 (d, 2.1) | 106.5 | C-3a, 4, 5a |
| 3-OCH3 | 3.90 (s) | 55.6 | C-3 | 3.85 (s) | 56.1 | C-3 | 4.22 (s) | 60.6 | C-3 |
| 5-OCH3 | 3.90 (s) | 55.6 | C-5 | 3.85 (s) | 56.1 | C-5 | – | – | – |
| 9-OCH3 | 3.74 (s) | 50.7 | C-9 | 3.75 (s) | 52.0 | C-9 | 3.69 (s) | 51.5 | C-9 |