Abstract
Theoretical studies were done on calcium channel drugs in order to gain insight into the mode of action. Empirical force field calculations with nifedipine, a calcium channel antagonist, indicate that the E-conformation at the ring juncture is lower in energy than the Z-conformation. This energy difference is only 0.2 kcal/mol when the esters in the 3- and 5-positions of the dihydropyridine (DHP) ring are both synperiplanar (sp, sp). Molecular orbital calculations on the ground and excited states in the Z-conformation with the esters in the (ap, sp) conformation show a low lying excited state with substantial intramolecular electron transfer (ET) character. This excited state is only 1.8 eV higher in energy than the ground state and corresponds to a transfer of approximately 0.3 electron from the DHP ring to the nitrobenzene moiety. We suggest that ET may play an important role in the mechanism of action, either intramolecular or, as previously proposed, intermolecular, along with lipophilicity and steric effects.
| Original language | English |
|---|---|
| Pages (from-to) | 61-70 |
| Number of pages | 10 |
| Journal | Chemico-Biological Interactions |
| Volume | 75 |
| Issue number | 1 |
| DOIs | |
| State | Published - 1990 |
Funding
WDE acknowledges a seed grant from the University of Idaho Research Council and generous start-up funds for the components of the Computational Facility for Theoretical Chemistry. WDE and NRN thank the National Science Foundation's EPSCOR program for grant #Rll-8902065. NRN thanks the Idaho State Board of Education (Grant No. 88-056) and the National Institutes of General Medical Sciences (Grant No. 1-R-15-GM42029-01) for generous support.
| Funder number |
|---|
| 1-R-15-GM42029-01 |
| -8902065 |
| 88-056 |
Keywords
- Calcium channel drugs - Empirical force field calculations - Molecular quantum mechanics - Mechanism of action - Electron transfer