Derivatives of the closo-Decaborate Anion with Pendant Functional Groups as Inhibitors of Viral Replication

Abstract

The reaction between the 1,4-dioxane derivative of the closo-decaborate anion [2-B10H9O(CH2)4O]– with cyanide, hydrophthalate, and hydroiminoacetate ions has been studied. Alkali metal salts (K, Na, and Cs) of the closo-decaborate anion derivatives with pendant groups –NHCH2CH2NH2-, –OOC(o-C6H4)COOH-, –OOCCH2NHCH2COOH-, –OCH2CH2OH-, –CN-, –SCN-, and –SH- have been isolated. All compounds have been shown to have extremely low cytotoxicity (CT50 ~ 1000 μg/mL). It has been found that compounds Na2[B10H9O(CH2)2O(CH2)2SCN] and Na2[B10H9O(CH2)2O(CH2)2CN] exhibit activity and selectivity in vitro against the modern strain of SARS-CoV-2 coronavirus (IC50 312 and 625 μg/mL, respectively). In relation to influenza A virus and rabies virus, the compounds show weak antiviral activity at high concentrations (1250 μg/mL), i.e. show no selective effect on the reproduction of these viruses.