Table 1. NMR spectroscopic data for caulamidine A (1) in CD3CN.
| Position | δ C | δ N a | δ H (mult, J in Hz) | HMBC b |
| 1-N | — | 78.9 | — | — |
| 2 | 174.0 | — | — | |
| 3-N | — | 241.7 | — | — |
| 4 | 156.0 | — | — | — |
| 5 | 117.8 | — | 7.17 (d, 8.5) | 3, 4, 6, 7, 9 |
| 6 | 129.4 | — | 7.31 (dd, 8.4, 2.0) | 4, 5, 7, 8 |
| 7 | 126.3 | — | — | — |
| 8 | 123.8 | — | 6.95 (bs) | 4, 6, 7, 10 |
| 9 | 133.3 | — | — | — |
| 10 | 58.9 | — | — | — |
| 11 | 54.8 | — | 5.02 (dd, 10.8, 4.7) | 2, 9, 10, 12, 23 |
| 12a | 52.6 | — | 3.87 (dd, 13.3, 6.6) | 11, 13, 14, 15, 27 |
| 12b | 3.66 (dd, 13.3, 10.5) | 11, 13, 14, 15 | ||
| 13-N | — | 87.5 | — | — |
| 14 | 159.1 | — | — | — |
| 15-N | — | 216.6 | — | — |
| 16 | 143.9 | — | — | — |
| 17 | 124.2 | — | 6.94 (d, 8.2) | 15, 16, 19, 21 |
| 18 | 127.2 | — | 7.12 (dd, 8.2, 2.4) | 16, 19 |
| 19 | 125.8 | — | — | — |
| 20 | 127.3 | — | 6.96 (s) | 16, 18, 19, 21, 22 |
| 21 | 125.4 | — | — | — |
| 22a | 29.6 | — | 2.48 (d, 15.9) | 10, 14, 16, 21, 23, 24 |
| 22b | 2.28 (d, 15.9) | 10, 13, 14, 16, 21, 23, 24 | ||
| 23 | 39.8 | — | — | — |
| 24a | 24.7 | — | 2.25 (m) | 10, 14, 22, 23, 25 |
| 24b | 1.73 (dd, 15.0, 6.2) | 1, 10, 22, 23, 25 | ||
| 25a | 47.4 | — | 3.38 (ddd, 12.5, 7.5, 1.6) | 2, 3, 24 |
| 25b | 3.18 (dt, 11.7, 5.9) | 24, 26 | ||
| 26 | 37.2 | — | 3.00, 3H (s) | 1, 2, 3, 25 |
| 27 | 35.8 | — | 3.24, 3H (s) | 12, 13, 14, 15 |
a 15N assignments were based on 1H–15N HMBC correlations. The δN values were not calibrated to an external standard but were referenced to neat NH3 (δ 0.00) using the standard Bruker parameters.
b 1H–13C (optimized for 8.3 Hz) and 1H–15N (optimized for 8 Hz) HMBC correlations are listed.