Table 1.
Summary of Computed NMR Results for 1–4
| Atom Label | Exp. δ (p.p.m) | 1 | 2 | 3 | 4 |
|---|---|---|---|---|---|
| C1 | 177.5 | 173.71 | 183.54 | 175.33 | 174.74 |
| C2 | 32.8 | 31.70 | 32.50 | 33.94 | 32.58 |
| C3 | 124.5 | 132.82 | 130.96 | 126.86 | 125.76 |
| C4 | 109.6 | 123.00 | 107.00 | 104.31 | 108.17 |
| C4a | 128.8 | 130.18 | 125.56 | 123.76 | 127.78 |
| C5 | 119.5 | 120.13 | 119.4 | 119.68 | 119.75 |
| C6 | 119.7 | 127.62 | 118.30 | 118.62 | 118.87 |
| C7 | 122.3 | 125.95 | 122.11 | 122.36 | 122.18 |
| C8 | 112.1 | 113.71 | 109.64 | 108.70 | 111.45 |
| C8a | 138.0 | 138.30 | 137.32 | 134.07 | 135.98 |
| MAD | 4.21 | 2.34 | 2.46 | 1.07 | |
| H2 | 3.68 | 3.44 | 3.44 | 3.54 | 3.78 |
| H3 | 7.14 | 5.60 | 7.10 | 7.14 | 7.18 |
| H5 | 7.54 | 7.15 | 7.42 | 7.52 | 7.61 |
| H6 | 6.99 | 7.18 | 7.11 | 7.16 | 7.15 |
| H7 | 7.07 | 7.19 | 7.28 | 7.27 | 7.24 |
| H8 | 7.33 | 7.12 | 7.56 | 7.41 | 7.40 |
| MAD | 0.45 | 0.16 | 0.10 | 0.10 |
a
Abbreviation: MAD, mean absolute deviation. Deviations of less than 6 ppm for 13C and less than 0.3 ppm for H shifts are considered acceptable.9−11 Chemical shifts exceeding the accepted deviations are bolded.