Table 1. Ktrans/cis of Ac-(2S)-Ind-OMe (1) Obtained from 1H NMR Spectroscopy of 0.1M Solutions in Different Deuterated Solvents at 298 K.
| solvent | Ktrans/cis | δ (ppm) transa | δ (ppm) cisa | εrb |
|---|---|---|---|---|
| C6D6 | 0.72 | 5.06 | 4.14 | 2.3 |
| CDCl3 | 0.87 | 5.17 | 4.91 | 4.8 |
| CD2Cl2 | 0.63 | 5.10 | 4.93 | 8.9 |
| CD3OD | 0.47 | 5.15 | 5.22 | 32.7 |
| CD3CN | 0.43c | 5.04 | 5.04 | 37.5 |
| DMSO-d6 | 0.31 | 5.02 | 5.30 | 46.7 |
a
Chemical shift values of the Hα of the trans and cis conformer.
b
Solvent dielectric constant.
c
For CD3CN, Ktrans/cis was calculated through the ratio between the integrated areas of the CH3 acetamide signals of the two isomers.