Title

Synthesis and Biological Testing of Small-Molecule Mitochondrial Complex I Inhibitors

Author

Willough Sloan, William & MaryFollow

Date Thesis Awarded

12-2022

Access Type

Honors Thesis -- Open Access

Degree Name

Bachelors of Science (BS)

Department

Chemistry

Advisor

Dana Lashley

Committee Members

Robert Pike

Randolph Coleman

Oliver Kerscher

Abstract

This thesis delineates two main projects: the first outlines the structure elucidation efforts toward a Diels-Alder adduct of a novel reaction for the synthesis of chimaphilin, a naphthoquinone-based natural product with apoptotic or antiproliferative activity in certain cancer cells^1,2. The structure elucidation extends to derivatives of chimaphilin synthesized by the same cyclization reaction. While Diels-Alder reactions are usually regioselective, ¹H-NMR and ¹³C-NMR of the adducts was inconclusive and indicated the possibility of regioisomer presence, with one regioisomer being chimaphilin (or derivatives). A multitude of crystallization methods were carried out in order to be able to analyze the products via X-ray crystallography. An unusual chimaphilin [2+2] cycloaddition dimer was discovered, indicating the correct positioning of the methyl group at C6 of the naphthoquinone scaffold. A phenyl derivative of chimaphilin was also crystallized to reveal a mixture of regioisomers with substituents positioned at C6 or C7 respectively.

The second project marks the auspicious beginnings of a Structure-Activity Relationship (SAR) study based on hit compound EVP4593, a known mitochondrial complex I (MCI) inhibitor³. The intention of this SAR study is the design of an improved MCI inhibitor for use as a potential anticancer agent. A series of derivatives of EVP4593 were synthesized, purified, and analyzed spectroscopically. Biological testing was conducted both in vitro on in-membrane NADH, succinate, and dNADH oxidases and on isolated bd-I and bd-II oxidases from Escherichia coli (E. coli) and in vivo against a genetic knockout library of >5100 Saccharomyces cerevisiae (S. cerevisiae) strains, revealing that the compound titled “H-EVP1” was the most potent inhibitor out of the tested EVP4593 derivatives and was possibly selective for MCI when compared to other oxidases.

Recommended Citation

Sloan, Willough, "Synthesis and Biological Testing of Small-Molecule Mitochondrial Complex I Inhibitors" (2022). Undergraduate Honors Theses. William & Mary. Paper 1900.
https://scholarworks.wm.edu/honorstheses/1900