Table 2.
NMR Dataa (DMSO-d6) for natural 6-Br-8-keto-conicamin A (2), synthetic 6-Br-8-keto-conicamin (2a), and synthetic 5-Br-8-keto-conicamin A (3).
| position | 2
|
2a
|
3
|
||||
|---|---|---|---|---|---|---|---|
| δC, Typeb | δH, mult (J, Hz) | HMBCc | δC | δH, mult (J, Hz) | δC | δH, mult (J, Hz) | |
| 1 | 8.47, bs | 8.51, s | 8.54, s | ||||
| 2 | 136.9, CH | 8.58, bs | 3, 3a, 7a | 138.2 | 8.51, s | 138.8 | 8.52, s |
| 3 | 114.6, C | – | 114.5 | – | 114.1 | – | |
| 3a | 124.3, C | – | 124.8 | – | 127.7 | – | |
| 4 | 122.7, CH | 8.08, d (8.5) | 3, 3a, 5, 7, 7a | 122.5 | 8.07, d (8.5) | 123.0 | 8.27, s |
| 5 | 125.4, CH | 7.39, dd (1.3, 8.5) | 3a, 7 | 125.0 | 7.35, bd (8.5) | 115.6 | – |
| 6 | 115.9, C | – | 115.5 | – | 125.4 | 7.34, d (8.4) | |
| 7 | 115.6, CH | 7.77, bs | 3a, 5, 6, 7a | 116.1 | 7.78, bs | 114.8 | 7.54, d (8.6) |
| 7a | 138.1, C | – | 139.5 | – | 137.6 | – | |
| 8 | 185.4, C | – | 184.6 | – | 184.4 | – | |
| 9 | 66.1, CH2 | 4.99, s | 8, N-(CH3)3 | 66.1 | 4.90, s | 66.0 | 4.91, s |
| N-(CH3)3 | 53.5, CH3 | 3.33, s | 9 | 53.5 | 3.31, s | 53.5 | 3.32, s |
a
Measured at 600 MHz (1H) and 150 MHz (13C);
b
Carbon type determined by gHSQC;
c
gHMBC(AD) correlations to indicated carbon with JnCH optimized for 6 Hz couplings and using a two second relaxation delay.