Table 4.
1H-NMR (300 MHz, MeOH-d4, TMS; δH in ppm, J in Hz) and 13C-NMR (75 MHz, MeOH-d4, TMS, δC in ppm) spectral data of aucubin (43) and ajugol (42) isolated from flowers of Verbascum calvum.
| Proton/Carbon | Aucubin (43) | Ajugol (42) | ||
|---|---|---|---|---|
| 1H a | 13C b | 1H a | 13C b | |
| 1 | 1H, 4.96 d (7.0) | 97.7 (CH) | 1H, 5.47 d (2.2) | 93.7 (CH) |
| 3 | 1H, 6.31 dd (6.0 and 1.8) | 141.6 (CH) | 1H, 6.16 dd (6.3 and 1.9) | 140.4 (CH) |
| 4 | 1H, 5.10 dd (6.0 and 4.0) | 105.7 (CH) | 1H, 4.78–4.82 (m) | 105.9 (CH) |
| 5 | 1H, 2.60–2.70 (m) | 46.3 (CH) | 1H, 2.69–2.74 (m) | 41.2 (CH) |
| 6 | 1H, 4.39–4.48 (m) | 82.8 (CH) | 1H, 3.90 ddd (5.6, 5.0, and 3.0) | 78.0 (CH) |
| 7 | 1H, 5.76 br s (t) | 130.3 (CH) | 1H, 1.79 dd (13.5, 5.0);1H, 2.05 dd (13.5 and 5.6) | 50.0 (CH2) |
| 8 | - | 148.0 (C) | - | 79.5 (C) |
| 9 | 1H, 2.89 br t (7.2) | 47.9 (CH) | 1H, 2.53 dd (9.5 and 2.2) | 51.8 (CH) |
| 10 | 2H, ABq centered at 4.25 (15.4) | 61.4 (CH2) | 3H, 1.30 s | 25.2 (CH3) |
| 1′ | 1H, 4.68 d (7.8) | 99.9 (CH) | 1H, 4.63 d (7.9) | 99.4 (CH) |
| 2′ | 1H, 3.21 dd (7.8 and 9.0) | 74.9 (CH) | 1H, 3.21 dd (8.0 and 9.0) | 74.8 (CH) |
| 3′ | 1H, 3.34 t (9.0) | 77.9 (CH) | 1H, 3.30–3.37 m | 77.8 (CH) |
| 4′ | 1H, 3.28 t (9.0) | 71.6 (CH) | 1H, 3.20–3.25 m | 71.7 (CH) |
| 5′ | 1H, 3.28–3.33 m | 78.3 (CH) | 1H, 3.28–3.33 m | 78.2 (CH) |
| 6′ | 1H, 3.65 dd (12.2 and 5.2);1H, 3.87 dd (12.2 and 1.5) | 62.7 (CH2) | 1H, 3.66 dd (12.0 and 5.2);1H, 3.91 dd (12.0 and 1.5) | 62.9 (CH2) |
a Proton assignments are based on COSY and HSQC experiments. b The number of hydrogens attached to each carbon was determined by DEPT experiments. Carbon assignments were established by HSQC and HMBC experiments.