Table 1.
1H and 13C NMR spectral data for diterpene 4.
| δC | δH (J [Hz]) | HMBC[a] | ||
|---|---|---|---|---|
| 1 | CH-O | 72.6 | 3.35, d (9.5) | 2, 14, 15, 16 |
| 2 | C | 38.0 | ||
| 3 | CH2 | 39.0 | 2.30, dd (14.2, 9.4); 1.68, dd (14.2, 6.2) | 1, 4, 5, 17 |
| 4 | CH= | 120.8 | 5.16, t (7.8) | 18 |
| 5 | C= | 135.3 | ||
| 6 | CH2 | 38.7 | 2.11, m; 2.07, m | 8 |
| 7 | CH2 | 24.4 | 2.22, t (3.5); 2.16, m | 6, 8, 9 |
| 8 | CH= | 124.4 | 4.94, t (6.0) | 6, 7, 10 |
| 9 | C= | 134.2 | ||
| 10 | CH2 | 39.2 | 2.07, t (6.9) | 9, 12 |
| 11 | CH2 | 24.7 | 2.16, m; 2.07, t (6.9) | 9, 12 |
| 12 | CH= | 125.5 | 5.05, t (5.9) | 11, 14, 20 |
| 13 | C= | 134.0 | ||
| 14 | CH2 | 35.1 | 2.19, m; 1.99, m | 1, 12, 15, 20 |
| 15 | CH2 | 27.4 | 1.55, m; 1.28, m | 1 |
| 16 | CH3 | 24.0 | 0.83, s | 1, 3, 17 |
| 17 | CH3 | 22.9 | 0.87, s | 3, 16 |
| 18 | CH3 | 16.5 | 1.61, s | 4, 5, 6 |
| 19 | CH3 | 16.1 | 1.54, s | 8, 9, 10 |
| 20 | CH3 | 16.0 | 1.58, s | 12, 13, 14 |
The data were recorded in CDCl3.
[a]
Proton showing HMBC correlation to indicated carbon.