Synthesis of Triphenylphosphonium-Linked Derivative of 3,5-Di tert-butyl-4-hydroxybenzylidene-malononitrile (SF6847) via Knoevenagel Reaction Yields an Effective Mitochondria-Targeted Protonophoric Uncoupler

Roman S Kirsanov; Ljudmila S Khailova; Tatyana I Rokitskaya; Konstantin G Lyamzaev; Alisa A Panteleeva; Pavel A Nazarov; Alexander M Firsov; Iliuza R Iaubasarova; Galina A Korshunova; Elena A Kotova; Yuri N Antonenko

doi:10.1021/acsomega.3c08621

Synthesis of Triphenylphosphonium-Linked Derivative of 3,5-Di tert-butyl-4-hydroxybenzylidene-malononitrile (SF6847) via Knoevenagel Reaction Yields an Effective Mitochondria-Targeted Protonophoric Uncoupler

ACS Omega. 2024 Feb 29;9(10):11551-11561. doi: 10.1021/acsomega.3c08621. eCollection 2024 Mar 12.

Affiliations

¹ Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia.
² The "Russian Clinical Research Center for Gerontology" of the Ministry of Healthcare of the Russian Federation, Pirogov Russian National Research Medical University, 117997 Moscow, Russia.

Abstract

Mitochondrial uncouplers are actively sought as potential therapeutics. Here, we report the first successful synthesis of mitochondria-targeted derivatives of the highly potent uncoupler 3,5-ditert-butyl-4-hydroxybenzylidene-malononitrile (SF6847), bearing a cationic alkyl(triphenyl)phosphonium (TPP) group. As a key step of the synthesis, we used condensation of a ketophenol with malononitrile via the Knoevenagel reaction. SF-C₅-TPP with a pentamethylene linker between SF6847 and TPP, stimulating respiration and collapsing membrane potential of rat liver mitochondria at submicromolar concentrations, proved to be the most effective uncoupler of the series. SF-C₅-TPP showed pronounced protonophoric activity on a model planar bilayer lipid membrane. Importantly, SF-C₅-TPP exhibited rather low toxicity in fibroblast cell culture, causing mitochondrial depolarization in cells at concentrations that only slightly affected cell viability. SF-C₅-TPP was more effective in decreasing the mitochondrial membrane potential in the cell culture than SF6847, in contrast to the case of isolated mitochondria. Like other zwitterionic uncouplers, SF-C₅-TPP inhibited the growth of Bacillus subtilis in the micromolar concentration range.