A new lactone, 7-epi-griffonilide (1), and six known compounds, 2, 3a - 3c, 4a and 4b, were isolated from the leaves of Bauhinia pentandra (Fabaceae). The structures elucidation of 1 and 2 were based on detailed 2D NMR techniques and spectral comparison with related compounds, leading to complete assignment of the 1H and 13C NMR spectra.
Key words:
Bauhinia pentandra; Fabaceae; cyanoglucoside; lactones; RMN.
| Position | 1 | 5 (Griffonilide) | |||
|---|---|---|---|---|---|
| dC | dH (J in Hz) | HMBC (J H-C) | dC | dH (J in Hz) | |
| 1 | 176.7 | - | 175.8 | - | |
| 2 | 113.3 | 5.89 (s) | C1, C3, C4, C8 | 112.5 | 5.89 (d, ~2.0) |
| 3 | 163.3 | - | 164.7 | - | |
| 4 | 121.0 | 6.63 (dd, 10.0, 2.5) | C3, C6, C8 | 120.6 | 6.62 (dd, 9.5, 2.5) |
| 5 | 143.0 | 6.16 (d, 10.0) | C3, C7 | 144.2 | 6.27 (dd, 9.5, 1.9) |
| 6 | 70.1 | 4.52 (br s) | 73.6 | 4.33 (dt, 7.6, 2.5, 1.9) | |
| 7 | 72.8 | 4.49 (br s) | C3, C5, C8 | 80.0 | 3.53 (dd, 10.8, 7.6) |
| 8 | 83.5 | 5.11 (br s) | C2, C3 | 85.1 | 4.90 (dd, 10.8, 1.9) |
| Position | 2 | Dasycarponilide | |||
|---|---|---|---|---|---|
| dC | dH (J in Hz) | HMBC (J H-C) | dC | dH (J in Hz) | |
| 1 | 176.7 | - | 175.8 | - | |
| 2 | 113.4 | 5.90 (d, 1.8) | C1, C3, C4, C8 | 113.3 | 5.90 (d, 1.9) |
| 3 | 164.5 | - | 164.3 | - | |
| 4 | 123.4 | 6.70 (d, 9.6) | C2, C3, C5, C6, C8 | 123.3 | 6.69 (d, 9.5) |
| 5 | 139.8 | 6.42 (dd, 9.6, 5.5) | C3, C4, C6, C7 | 139.7 | 6.41 (dd, 9.5, 5.4) |
| 6 | 68.7 | 4.40 (dd, 5.3, 4.2) | C4, C5, C7, C8 | 68.7 | 4.39 (dd, 5.4, 4.1) |
| 7 | 74.5 | 3.64 (dd, 10.4, 4.2) | C3, C8 | 74.4 | 3.63 (dd, 10.5, 4.1) |
| 8 | 83.5 | 5.23 (dd, 10.4, 1.7) | C3, C7 | 83.4 | 5.22 (dd, 10.5, 1.9) |
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