TABLE 2
1H and 13C chemical shift assignments of carbazeran and the AO metabolite
Carbazeran  | Carbazeran M1  | |||
|---|---|---|---|---|
| 1H (Multiplicity, Integration, Coupling Constant) | 13C | 1H (Multiplicity, Integration, Coupling Constant) | 13C | |
| 1 | 159.1 | 149.2 | ||
| 3 | 11.97 (s,1) | |||
| 4 | 9.11 (s, 1) | 147.4 | 159.1 | |
| 4a | 124.9 | 123.3 | ||
| 5 | 7.50 (s, 1) | 106.5 | 7.58 (s, 1) | 106.6 |
| 6 | 153.6 | —c | 152.7 | |
| H3CO-6 | 3.98 (s, 3)b | 56.5 | 3.93 (s, 3)a | 56.3 |
| 7 | 153.6 | —c | 153 | |
| H3CO-7 | 3.98 (s, 3)a | 56.2 | 3.95 (s, 3)a | 56 |
| 8 | 7.22 (s, 1) | 103.0 | 7.17 (s, 1) | 105.3 |
| 8a | 116.5 | 121.6 | ||
| 2′/6′ | 3.21/3.63 (cm, 2/2) | 48.5 | 2.91/3.28 (cm, 2/2) | 48.6 |
| 3′/5′ | 1.82/2.08 (cm, 2/2) | 31.3 | 1.76/2.02 (cm, 2/2) | 31.3 |
| 4 | 4.78 (cm, 1) | 69.8 | 4.71 (cm, 1) | 69.3 |
| Ethyl carbamate CO | —a | 155.6 | ||
| Ethyl carbamate NH | 7.10 (t, 1, j = 5.8 Hz) | 7.09 (t, 1, j = 5.3 Hz) | ||
| Ethyl carbamate CH2 | 3.03 (cm, 2) | 35.4 | 3.01 (cm, 2) | 35.2 |
| Ethyl carbamate CH3 | 1.02 (t, 3, j = 7.3 Hz) | 15.5 | 1.02 (t, 3, j = 7.2 Hz) | 15.8 |
| Citric acid | ||||