Table 1.
NMR spectral data for the major conformer of largamide D oxazolidine (1) and largamide D (2) [24].
| Unita | 1 (DMF-d7) δH (J in Hz) |
δC | COSY | HMBC | 1 (methanol-d4) δH (J in Hz) |
δC | 2 (methanol-d4) δH (J in Hz) |
δC | |
|---|---|---|---|---|---|---|---|---|---|
| Val-1 | 1 | 171.4 | 173.6 | 174.8 | |||||
| 2 | 4.53, m | 56.8 | H-3, NH | 1, 3, 4, 5, 1 (N-Me-Br-Tyr) | 4.72, m | 58.1 | 4.49, d (7.4) | 58.9 | |
| 3 | 2.32, m | 31.1 | H-2, H3-4, H3-5 | 2, 4, 5 | 2.38, m | 32.7 | 2.15, m | 31.8 | |
| 4 | 0.92, d (7.0) | 19.0 | H-3 | 2, 3, 5 | 0.92, d (7.2) | 18.8 | 0.93, d (6.9) | 18.9 | |
| 5 | 0.86, d (7.0) | 17.5 | H-3 | 2, 3, 4 | 0.89, d (7.2) | 18.0 | 0.99, d (6.9) | 19.8 | |
| NH | 6.76, d (8.3) | H-2 | |||||||
| N-Me- Br-Tyr | 1 | 169.2 | 170.9 | 171.4 | |||||
| 2 | 5.71, dd (11.5, 2.5) | 62.5 | H-3a/3b | 1 | 5.75, dd (11.5, 2.4) | 63.9 | 5.06, dd (11.5, 3.1) | 62.6 | |
| 3a | 3.34, dd (−14.3, 11.5) | 32.4 | H-2, H-3b H-2, H-3a |
2, 4 | 3.28, dd (−14.4, 2.4) | 33.5 | 3.40, dd (−14.6, 3.1) | 33.8 | |
| 3b | 2.89, dd (−14.3, 2.5) | 2.84, dd (−14.4, 11.5) | 2.80, m | ||||||
| 4 | 130.5 | 131.4 | 130.4 | ||||||
| 5 | 7.44, d (1.9) | 133.8 | 4, 6, 7, 9 | 7.32, d (1.2) | 134.8 | 7.34, d (2.0) | 134.8 | ||
| 6 | 109.3 | 111.2 | 110.8 | ||||||
| 7 | 153.6 | 154.7 | 154.4 | ||||||
| 8 | 7.03, d (8.2) | 116.7 | H-9 | 4, 6, 7, 9 | 6.83, d (8.3) | 117.7 | 6.87, d (8.2) | 117.6 | |
| 9 | 7.13, dd (8.2, 1.9) | 129.9 | H-8 | 5, 8 | 7.02, dd (8.3, 1.2) | 130.8 | 7.17, dd (8.2, 2.0) | 130.7 | |
| N-Me | 2.92, s | 30.8 | 1, 2, 1 (Thr-1) | 2.90, s | 31.8 | 2.87, s | 31.2 | ||
| Thr-1a | 1 | 169.7 | 172.0 | 173.0 | |||||
| 2 | 4.04, d (3.4) | 59.5 | H-3 | 1, 3, 2 (Ahp), H-6 (Ahp) | 3.96, d (2.3) | 61.0 | 4.57, d (6.8) | 55.9 | |
| 3 | 4.36, qd (6.4, 3.4) | 76.4 | H3-4 | 1, 2, 4 | 4.38, dq (6.2, 2.3) | 77.4 | 3.74, m | 66.6 | |
| 4 | 0.71, d (6.4) | 19.4 | H-3 | 2, 3 | 0.70, d (6.2) | 20.5 | 0.57, d (6.2) | 19.6 | |
| Ahpa | 2 | 168.8 | 170.5 | 171.3 | |||||
| 3 | 4.63, ddd (12.4, 8.7, 4.9) | 50.3 | H-4a/4b, NH | 2, 4, 5, 6 | 4.63, dd (9.9, 5.3) | 51.7 | 4.64, dd (12.4, 6.4) | 50.7 | |
| 4a | 1.95, m | 24.6 | H-3, H-4b, H-5a/5b | 2, 3, 5, 6 | 1.97, m | 25.3 | 2.82, m | 22.0 | |
| 4b | 1.88, m | H-3, H-4a, H-5a/5b | 1.93, m | 1.88, m | |||||
| 5a | 2.38, m | 27.9 | H-4a/4b, H-5b, H-6 | 3, 4, 6 | 2.40, m | 29.2 | 2.04, m | 30.6 | |
| 5b | 1.68, m | H-4a/4b, H-5a, H-6 | 1.66, m | 1.87, m | |||||
| 6 | 5.01, dd (8.5, 6.2) | 87.4 | H-5a/5b | 2, 4, 5 | 5.03, dd (8.5, 6.5) | 88.6 | 5.33, brs | 76.9 | |
| NH | 7.22, d (8.7) | H-3 | 3, 1 (Leu) | ||||||
| Leu | 1 | 171.7 | 174.6 | 174.4 | |||||
| 2 | 4.49, m | 51.4 | H-3a/3b | 1, 3 | 4.58, dd (11.0, 3.0) | 52.6 | 4.56, dd (8.5, 3.3) | 52.9 | |
| 3a | 1.84, m | 40.6 | H-2, H-3b | 1, 2, 4 | 1.88, m | 41.3 | 1.98, ddd (12.6, 12.6, 3.3) | 40.2 | |
| 3b | 1.47, m | H-2, H-3a | 1.47, m | 1.55, m | |||||
| 4 | 1.61, m | 24.5 | H-3a/3b, H3-5, H3-6 | 2, 3, 5, 6 | 1.56, m | 25.8 | 1.65, m | 25.8 | |
| 5 | 0.87, d (6.6) | 22.9 | H-4 | 4 | 0.91, d (6.0) | 23.8 | 0.87, d (6.8) | 20.0 | |
| 6 | 0.82, d (6.6) | 20.8 | H-4 | 4 | 0.83, d (6.0) | 21.5 | 0.97, d (6.7) | 23.7 | |
| NH | 8.50, d (8.5) | H-2 | 2, 1 (Thr-2) | ||||||
| Thr-2 | 1 | 169.7 | 171.1 | 170.9 | |||||
| 2 | 4.92, dd (9.0, 1.7) | 55.4 | NH | 1, 3, 1 (Val-2) | 4.72, m | 56.7 | 4.78, d (1.2) | 56.3 | |
| 3 | 5.78, qd (6.0, 1.7) | 72.1 | H3-4 | 1, 2, 4, 1 (Val-1) | 5.64, qd (6.5, 1.4) | 73.2 | 5.59, qd (6.5, 1.2) | 73.4 | |
| 4 | 1.33, d (6.0) | 16.6 | H-3 | 2, 3 | 1.30, d (6.5) | 17.7 | 1.36, d (6.5) | 18.1 | |
| NH | 8.25, d (9.0) | H-2 | 2, 1 (Val-2) | ||||||
| Val-2 | 1 | 171.7 | 173.8 | 173.9 | |||||
| 2 | 4.53, dd (8.6, 5.5) | 58.0 | H-3, NH | 1, 3, 4, 5 | 4.30, d (7.8) | 60.2 | 4.39, d (7.4) | 59.7 | |
| 3 | 2.17, m | 31.2 | H-2, H3-4, H3-5 | 2, 4, 5 | 2.09, dd (7.8, 6.8) | 32.0 | 2.17, m | 31.9 | |
| 4 | 0.90, d (7.0) | 18.5 | H-3 | 2, 3, 5 | 0.94, d (6.8) | 18.8 | 0.98, d (6.9) | 18.5 | |
| 5 | 0.87, d (7.0) | 17.5 | H-3 | 2, 3, 4 | 0.90, d (6.8) | 19.4 | 0.98, d (6.9) | 19.8 | |
| NH | 7.76, d (8.6) | H-2 | 2, 1 (Ala) | ||||||
| Ala | 1 | 172.0b | 174.8 | 174.4 | |||||
| 2 | 4.49, dq (9.0, 7.2) | 48.9 | H-3, NH | 1, 3 | 4.38, q (7.0) | 49.0 | 4.45, m | 49.9 | |
| 3 | 1.30, d (7.2) | 17.0 | H-2 | 1, 2 | 1.33, d (7.0) | 17.8 | 1.38, d (7.2) | 17.6 | |
| NH | 8.26, d (9.0) | H-2 | 2, 1 (Ahppa) | ||||||
| Ahppa | 1 | 171.9b | 174.1 | 173.5 | |||||
| 2 | 4.52, m | 52.6 | H-3a/3b, NH | 1, 3, 4, NH | 4.41, m | 54.4 | 4.46, m | 53.9 | |
| 3a | 1.89, m | 32.4 | H-2, H-3b, H-4a/4b | 2, 4, 5 | 1.87, m | 32.7 | 1.91, m | 32.6 | |
| 3b | 1.73, m | H-2, H-3a, H-4a/4b | 1.69, m | 1.73, m | |||||
| 4a | 1.68, m | 28.2 | H-3a/3b, H-4b | 2, 3, 5, 6 | 1.68, m | 29.0 | 1.70, m | 28.8 | |
| 4b | 1.62, m | H-3a/3b, H-4a | 1.63, m | 1.66, m | |||||
| 5 | 2.52, m | 34.2 | H-4a/4b | 3, 4, 6 | 2.54, m | 35.6 | 2.57, t (7.3) | 35.2 | |
| 6 | 132.6 | 134.0 | 133.6 | ||||||
| 7/11 | 7.03, d (8.3) | 129.8 | H-8/10 | 6, 8/10, 9 | 7.00, d (8.4) | 130.4 | 7.02, dd (8.2, 1.8) | 130.2 | |
| 8/10 | 6.76, d (8.3) | 115.2 | H-7/11 | 7/11, 9 | 6.67, d (8.4, 2.4) | 116.1 | 6.70, dd (8.2, 1.8) | 115.8 | |
| 9 | 156.0 | 7/11, 8/10 | 156.5 | 156.2 | |||||
| 9-OH | 9.36, s | 8/10, 9 | |||||||
| NH | 7.87, d (7.6) | H-2 | 1, 2, 1 (Ga) | ||||||
| Ga | 1 | 172.4 | 175.4 | 174.9 | |||||
| 2 | 4.11, m | 73.5 | H-3a/3b | 1, 3 | 4.11, d (3.5) | 74.2 | 4.13, t (3.8) | 73.9 | |
| 2-OH | c | ||||||||
| 3a | 3.76, dd (−10.9, 3.5) | 64.7 | H-2, H-3b | 1, 2 | 3.78, 2H, d (3.5) | 65.6 | 3.79, 2H, d (3.8) | 65.2 | |
| 3b | 3.70, dd (−10.9, 5.6) | H-2, H-3a |
a
The initial numbering from largamide D. (2) has been retained for comparison of data [24].
b
Can be interchanged.
c
Not observed.