Table 2.
1H and 13C NMR chemical shift differences for plocamenone (4) and isoplocamenone (5) (500 MHz, CD3OD).
| plocamenone (4) | isoplocamenone (5) | Differences (ppm) | ||||
|---|---|---|---|---|---|---|
| Position | δH | δCa | δH | δCa | ∆δH | ∆δC |
| 1a | 6.17, s | 132.3, (t) | 5.91, s | 129.0, (t) | +0.26 | +3.3 |
| 1b | 6.23, s | 6.00, s | +0.23 | |||
| 2 | - | 143.3, (s) | - | 143.5, (s) | −0.2 | |
| 3 | - | 193.2, (s) | - | 192.3, (s) | +0.9 | |
| 4 | - | 130.5, (s) | - | 133.7, (s) | −3.2 | |
| 5 | 6.39, s | 134.7, (d) | 6.84, s | 140.8, (d) | −0.45 | −6.1 |
| 6 | - | 70.7, (s) | - | 69.7, (s) | +1.0 | |
| 7 | 4.57, dd, (3, 9.5) | 63.5, (d) | 4.97, dd, (2.5, 9) | 61.5, (d) | −0.40 | +2.0 |
| 8a | 3.80, dd, (9.5, 12) | 47.6, (t) | 3.93, dd, (9, 13) | 47.1, (t) | −0.13 | +0.5 |
| 8b | 4.27, dd, (3, 12) | 4.37, dd (2.5, 13) | −0.10 | |||
| 9 | 1.93 | 16.6, (q) | 1.97, s | 18.0, (q) | −0.04 | −1.4 |
| 10 | 1.76 | 27.6, (q) | 2.05, s | 26.2, (q) | −0.29 | +1.4 |
a Carbon assignments based on gHSQCAD and gHMBC NMR experiments.