Consistent valence force-field parameterization of bond lengths and angles with quantum chemicalab initio methods applied to some heterocyclic dopamine D3-receptor agonists
✍ Scribed by Gaedt, Katrin; H�ltje, Hans-Dieter
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 251 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0192-8651
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✦ Synopsis
To secure a broad utilization of molecular mechanics in medicinal Ž . chemistry appropriate parameters e.g., reference values and force constants are required to describe correctly all possible atomic interactions. For this purpose parameters for bond lengths and bond angles were derived for some heterocyclic dopamine D -receptor agonists. Some new atom types were introduced and 3 Ž . consistent valence force-field CVFF was supplied with several bond-stretching and angle-bending force constants as well as reference values. Representative fragments containing these missing parameters were minimized at the HFr6-31G* level of theory using Gaussian-92. After frequency calculation, corresponding force constants were extracted from the Hessian matrix. The values were then appropriately converted and scaled. Also, reference values were taken from quantum mechanically minimized structures, applying the same basis set. The transferability of the calculated force constants to CVFF was investigated using fragments with already known parameters. The quality of the extended force field was checked in comparison with ''automatic parameters'' and ab initio-minimized structures. Finally, the evaluated procedure was applied successfully to related structures.