TABLE 2.
Assigned NMR data for catechin and products 1 and 3
| δ Value versus tetramethyl silane (position) [difference]a
| ||
|---|---|---|
| Catechin | Product 1 | Product 3 |
| 1H NMR spectrum | ||
| 2.45 (dd, 1H, H-4a) | 2.40 (H-4a) | 2.35 (H-4a) [−0.10] |
| 2.75 (dd, 1H, H-4b) | 2.70 (H-4b) | 2.70 (H-4b) |
| 3.92 (m, 1H, H-3) | 3.89 (H-3) [−0.03] | 3.85 (H-3) [−0.07] |
| 4.58 (d, 1H, H-2) | 4.60 (H-2) [+0.02] | 4.55 (H-2) [−0.03] |
| 4.95 (d, 1H, OH) | ||
| 5.79 (d, 1H, H-8) | 6.05 (H-8) [+0.26] | 5.70 (H-8) [−0.09] |
| 5.98 (d, 1H, H-6) | 6.16 (H-6) [+0.18] | 5.90 (H-6) [−0.08] |
| 6.69 (dd, 1H, H-6′) | 6.73 (H-6′) [+0.04] | 6.72 (H-6′) [+0.03] |
| 6.78 (d, 1H, H-5′) | 7.15 (H-5′) [+0.37] | 7.14 (H-5′) [+0.36] |
| 6.82 (d, 1H, H-2′) | 6.80 (H-2′) [−0.02] | 6.79 (H-2′) [−0.03] |
| 5.18 and 5.22 (H-1" gluc) | 5.17 (H-1" gluc) | |
| 13C NMR spectrum | ||
| 27.87 (C-4) | 27.75 | 27.86 |
| 60.62, 60.75 | 60.77 | |
| 66.37 (C-3) | 66.02 | 66.30 |
| 69.87–73.73 (8×) | 70.01–73.75 (4×) | |
| 81.04 (C-2) | 80.77 | 80.70 |
| 93.93 (C-8) | 95.50* and 96.72* [+1.57] | 93.87 |
| 95.19 (C-6) | 97.97* [+2.78] | 95.26 |
| 99.13 (C-10 [4a]) | 100.30* and 102.07* | 99.03* and 100.28* |
| 114.57 (C-2′) | 114.75 | 114.83 |
| 115.16 (C-5′) | 117.31 [+2.15] | 117.25 [+2.09] |
| 118.50 (C-6′) | 118.21 | 118.30 |
| 130.67 (C-1′) | 134.51 [+3.84] | 134.70 [+4.03] |
| 144.89 (C-3′ + C-4′) | 144.72 | 144.71 |
| 147.04 [+2.15] | 147.01 [+2.12] | |
| 155.42 (C-9 [8a]) | 155.11* | 155.24* |
| 156.23 (C-5) | 156.14* | 156.25* |
| 156.51 (C-7) | 156.57* | 156.54* |
a
δ Values are in parts per million. Values in brackets are differences between δ values for catechin and the corresponding values for product 1 or 3. *, assignments may be interchangeable.