Table 2 Rate constants and activation parameters for amide cis-trans isomerization
From: Amide nitrogen pyramidalization changes lactam amide spinning
|  |  | trans → cis | |||
|---|---|---|---|---|---|
|  | Solvent | kt→c (s−1) | ΔH‡t→c | ΔS‡t→c | ΔG‡t→ca |
|  |  | (kcal·mol−1) | (cal·mol−1·K−1) | (kcal·mol−1) | |
17(C9) | CD2Cl2 | 33.9b | 7.9 ± 0.5 | −15.6 ± 2.0 | 11.4 ± 0.1 |
18(C10) | CD2Cl2 | 3.9b | 9.2 ± 0.7 | −13.9 ± 3.3 | 12.3 ± 0.1 |
19(C11) | CD2Cl2 | 1.2b | 10.8 ± 0.8 | −9.1 ± 3.6 | 12.9 ± 0.2 |
16(C8) | CD3OD | 6.0b | 11.3 ± 0.3 | −3.5 ± 1.1 | 12.1 ± 0.1 |
17(C9) | CD3OD | 3.8b | 12.6 ± 0.6 | 1.4 ± 2.5 | 12.3 ± 0.1 |
18(C10) | CD3OD | 0.9b | 11.7 ± 0.7 | −5.8 ± 3.2 | 13.0 ± 0.1 |
Ac-Ah2c-NHMe c | CD3OD | 0.19d | 17.0 ± 1.0 | −2.2 ± 3.1 | 17.5 ± 1.9 |
|  |  | cis → trans | |||
|---|---|---|---|---|---|
|  | Solvent | kc→t (s−1) | ΔH‡c→t | ΔS‡c→t | ΔG‡c→ta |
|  |  | (kcal·mol−1) | (cal·mol−1·K−1) | (kcal·mol−1) | |
17(C9) | CD2Cl2 | 3.6b | 5.3 ± 0.3 | −31.9 ± 1.2 | 12.4 ± 0.1 |
18(C10) | CD2Cl2 | 11.4b | 9.3 ± 0.9 | −11.0 ± 4.2 | 11.8 ± 0.2 |
19(C11) | CD2Cl2 | 9.8b | 12.4 ± 0.9 | 2.2 ± 3.9 | 11.9 ± 0.2 |
16(C8) | CD3OD | 0.6b | 9.0 ± 0.7 | −18.4 ± 2.9 | 13.1 ± 0.1 |
17(C9) | CD3OD | 0.8b | 10.8 ± 0.9 | −9.9 ± 3.8 | 13.0 ± 0.2 |
18(C10) | CD3OD | 2.8b | 13.5 ± 0.9 | 4.7 ± 4.2 | 12.5 ± 0.1 |
Ac-Ah2c-NHMe c | CD3OD | 0.17d | 15.9 ± 0.3 | −6.6 ± 0.8 | 17.4 ± 0.5 |
