Research Article
1H and 13C NMR Assignments of Cytotoxic 3S-1,2,3,4-Tetrahydro-β-carboline-3-carboxylic Acid from the Leaves of Cichorium endivia
Table 1
1H and 13C NMR spectroscopic data for compound 1.
| | Number | | | | [4] | [5] | [5] |
| | 1a | 4.38 d (15.6) | 40.5 t | 4.15 d (15.3) | — | — | 40.3 | | 1b | 4.54 d (15.6) | | 4.23 d (15.9) | 4.22 d (4.8) | — | | | 3 | 4.27 dd (10.4, 5.6) | 55.0 d | 3.60 m | 3.14 | — | 55.3 | | 4a | 3.13 dd (10.8, 16.4) | 21.7 t | 2.81 dd-like | 2.83 ddd (10.5, 5.0, 2.4) | — | 18.0 | | 4b | 3.38 dd (5.6, 16.4) | | 3.13 br d-like | 3.69 dd (10.5, 5.0) | — | | | 4a′ | | 104.9 s | | | | 104.3 | | 4b′ | | 125.6f s | | | | 128.5 | | 5 | 7.53 d (8.0) | 118.2 d | 7.32 d (7.5) | 7.33 d (8.0) | 7.38 d (8.2) | 118.5 | | 6 | 7.13 t (7.6) | 120.0 d | 7.06 t (7.5) | 7.08 t (8.0) | 7.06 t (8.2) | 117.5 | | 7 | 7.22 t (8.0) | 122.9 d | 6.97 t (7.8) | 6.99 t (7.5) | 6.96 t (8.2) | 121.1 | | 8 | 7.43 d (8.0) | 111.9 d | 7.43 d (7.5) | 7.44 d (7.5) | 7.44 d (8.2) | 111.8 | | 8a | | 136.7 s | | | | 136.1 | | 9a | | 125.4f s | | | | — | | COOH | | 171.3 s | 10.91 s | 10.93 s | — | 165.6 | | 9-NH | | | | — | 10.66 s | |
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aD2O + drops of F3CCOOD; b400 MHz. c100 MHz. din DMSO-d6; e300 MHz. fAssignments may be interchanged.
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