Theoretical calculations on calcium channel drugs: Is electron transfer involved mechanistically?

Peter Kovacic*, W. Daniel Edwards, Nicholas R. Natale, Rajagopalan Sridhar, Patrick F. Kiser

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

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 languageEnglish (US)
Pages (from-to)61-70
Number of pages10
JournalChemico-Biological Interactions
Volume75
Issue number1
DOIs
StatePublished - 1990

Keywords

  • Calcium channel drugs - Empirical force field calculations - Molecular quantum mechanics - Mechanism of action - Electron transfer

ASJC Scopus subject areas

  • Toxicology

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