Table 1.
1H and 13C NMR Spectroscopic Data of MELs (δ in ppm, J in Hz).
| MEL-A a | MEL-B a | MEL-C b | ||||
|---|---|---|---|---|---|---|
| Functional Groups | 1H NMR δ (ppm) | 13C NMR δ (ppm) | 1H NMR δ (ppm) | 13C NMR δ (ppm) | 1H NMR δ (ppm) | 13C NMR δ (ppm) |
| D-Mannose | ||||||
| H-1′ (C-1′) | 5.50, d | 99.35 | 5.50, dd | 99.39 | 5.50, dd | 99.14 |
| H-2′ (C-2′) | 5.06, dd | 68.56 | 4.91, dd | 68.74 | 5.10, dd | 68.70 |
| H-3′ (C-3′) | 5.24, t | 70.60 | 4.77, m | 71.23 | 5.18, t | 70.64 |
| H-4′ (C-4′) | 4.72, d | 65.90 | 3.98, m | 65.64 | 4.77, d | 66.19 |
| H-5′ (C-5′) | 3.69, m | 72.55 | 3.85, m | 74.58 | 4.04, m | 74.88 |
| H-6′ (C-6′) a | 4.19, dd | 62.40 | 3.81, m | 63.15 | 3.77, m | 61.42 |
| H-6′ (C-6′) b | 4.24, dd | 62.40 | 4.43, m | 63.15 | 3.79, m | 61.42 |
| meso-Erythritol | ||||||
| H-1 (C-1) | 3.76, m | 63.60 | 3.72, m | 63.63 | 3.73, m | 63.48 |
| H-2 (C-2) | 3.66, m | 71.86 | 3.66, m | 73.12 | 3.65, m | 73.10 |
| H-3 (C-3) | 3.72, m | 71.19 | 3.77, m | 71.93 | 3.75, m | 71.10 |
| H-4a (C-4a) | 3.84, dd | 72.38 | 3.56, m | 72.23 | 3.68, m | 71.99 |
| H-4b (C-4b) | 3.99, dd | 72.38 | 3.75, m | 72.23 | 3.54, m | 71.99 |
| Acetyl group(s) | ||||||
| -CH3 | 2.09, 2.03, s | (20.75, 20.68) | 2.13, s | 20.86 | 2.06, s | 20.73 |
| -C=O | (170.76, 169.46) | 171.67 | 170.21 | |||
| Acyl groups | ||||||
| -CH3 | 0.86, m | (14.12, 14.11) | 0.87, m | (14.12, 14.07) | 0.88, m | (14.13, 14.07) |
| -(CH2)n- | 1.23–1.31, brs | (22.67–31.88) | 1.24–1.26, brs | (22.61–31.94) | 1.25–1.29, brs | (22.68–31.90) |
| -CO-CH2- (C-2′) position | 2.42, m | 34.16 | 2.40, m | 34.11 | 2.43, m | 34.11 |
| -CO-CH2- (C-3′) position | 2.21, m | 34.03 | 2.29, m | 34.20 | 2.22, m | 34.05 |
| -C=O | (173.43, 172.73) | (173.54, 172.41) | (173.59, 172.79) | |||
s, singlet; d, doublet; dd, double doublet; t, triplet; m, multiplet; brs, broad singlet. a Data were measured at 500 MHz for 1H and 126 MHz for 13C NMR in CDCl3; b Data were measured at 600 MHz for 1H and 151 MHz for 13C NMR in CDCl3.