Table 1.
The 1H NMR (500 MHz) and13C NMR (125 MHz) data of necbergamotenoic acid A (1), necbergamotenoic acid B (2) and its ionized form (2′)
| No | 1a |
2b |
2′b |
|||
|---|---|---|---|---|---|---|
| δH mult. (J in Hz) | δC | δH mult. (J in Hz) | δC | δH mult. (J in Hz) | δC | |
| 1a | 1.28, d (8.0) | 29.7 | 1.23, d (8.5) | 31.9 | 1.21, d (8.0) | 32.0 |
| 1b | 2.28, dd (8.0, 6.0) | 2.38, dd (8.5, 6.0) | 2.36, m | |||
| 2 | 2.26, d (6.0) | 43.5 | 2.30, m | 44.0 | 2.30–2.32c, m | 43.8 |
| 3 | 146.1 | 145.0 | 145.0 | |||
| 4 | 5.15, brs | 116.5 | 5.27, d (1.5) | 117.8 | 5.26, brs | 117.9 |
| 5a | 2.61, m | 31.7 | 2.20, m | 31.9 | 2.20, m | 32.0 |
| 5b | 2.24, m | 2.23, m | ||||
| 6 | 2.57, m | 39.3 | 2.36, m | 41.0 | 2.30–2.32c, m | 41.2 |
| 7 | 52.9 | 45.0 | 45.0 | |||
| 8a | 2.15, brt (6.0) | 33.4 | 1.95, dd (15.0, 3.5) | 42.2 | 1.95, dd (15.0, 4.0) | 42.8 |
| 8b | 2.05, dd (15.0, 9.5) | 1.98, dd (15.0, 8.5) | ||||
| 9 | 2.37, m | 24.9 | 4.70, ddd (9.5, 8.5, 3.5) | 67.1 | 4.63, ddd (9.5, 8.5, 4.0) | 67.3 |
| 10 | 6.81, t (6.0) | 144.9 | 6.74, dq (8.5, 1.0) | 145.9 | 6.53, dq (9.5, 1.0) | 141.1 |
| 11 | 128.0 | 128.3 | 133.7 | |||
| 12 | 173.7 | 171.6 | 177.6 | |||
| 13 | 1.78, s | 12.2 | 1.88, d (1.0) | 12.8 | 1.87, d (1.0) | 14.1 |
| 14a | 181.6 | 3.72, d (10.5) | 63.7 | 3.71, d (10.5) | 63.9 | |
| 14b | 3.37, d (10.5) | 3.30, d (10.5) | ||||
| 15 | 1.71, d (1.0) | 22.6 | 1.73, d (1.5) | 22.8 | 1.73, d (1.5) | 22.8 |
a
Recorded in CDCl3.
b
Recorded in CD3OD.
c
Overlapped.