Computational Study of Shuangancistrotectorine A …
189
a-b-g-h-i-u-q-v-x
a-b-g-h-i-u-q-t-y
a-b-g-h-i-u-p-v-y
a-b-g-h-i-u-q-t-x
b-c-g-h-i-u-p-v-y
a-d-g-h-u-i-q-t-y
a-d-g-h-i-u-p-v-y
b-c-g-h-i-u-q-v-x
a-d-g-h-i-u-q-v-x
a-d-g-h-i-u-q-t-x
b-c-g-h-i-u-q-t-x
b-c-g-h-i-u-q-t-y
c-d-g-h-i-u-p-v-y
c-d-g-h-i-u-q-t-x
c-d-g-h-i-u-q-v-x
c-d-g-h-i-u-q-t-y
Fig. 2 Optimized geometries of the calculated conformers of the shuangancistrotectorine A
molecule and acronyms denoting them. Geometries from HF/6-31G(d,p) results. The H atoms
are hidden to better highlight the structures, except for the H atoms of the OH groups (which are
usually engaged in IHBs). The initial part of the acronyms (SHA) is not reported under the images,
because of space reasons
Table 2 Relative energies of the calculated conformers of shuangancistrotectorine A HF/631G(d,p) and DFT/B3LYP/6-31+G(d,p) results in vacuo, respectively denoted as HF and DFT
in the columns’ headings
Conformers
Relative energy
(kcal/mol)
Conformers
Relative energy
(kcal/mol)
HF
DFT
HF
DFT
1-a-b-g-h-i-u-q-v-x
0.000
0.000
9-a-d-g-h-i-u-q-v-x
4.928
5.141
2-a-b-g-h-i-u-q-t-y
1.194
0.833
10-a-d-g-h-i-u-q-t-x
5.620
5.665
3-a-b-g-h-i-u-p-v-y
1.218
0.828
11-b-c-g-h-i-u-q-t-x
5.620
5.665
4-a-b-g-h-i-u-q-t-x
1.904
1.501
12-b-c-g-h-i-u-q-t-y
5.736
5.652
5-b-c-g-h-i-u-p-v-y
4.503
4.583
13-c-d-g-h-i-u-p-v-y
8.008
8.252
6-a-d-g-h-i-u-q-t-y
4.503
4.583
14-c-d-g-h-i-u-q-t-x
8.753
9.076
7-a-d-g-h-i-u-p-v-y
4.866
4.903
15-c-d-g-h-i-u-q-v-x
9.368
9.550
8-b-c-g-h-i-u-q-v-x
4.928
5.141
16-c-d-g-h-i-u-q-t-y
8.411
8.619
The absolute energies of the lowest energy conformer (hartree) are −2633.861716/HF and −
2650.476101/DFT