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

The reaction between the 1,4-dioxane derivative of the closo-decaborate anion [2-B10H9O(CH2)(4)O]- 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 similar to 1000 mu g/mL). It has been found that compounds Na-2[B10H9O(CH2)(2)O(CH2)(2)SCN] and Na-2[B10H9O(CH2)(2)O(CH2)(2)CN] exhibit activity and selectivity in vitro against the modern strain of SARS-CoV-2 coronavirus (IC50 312 and 625 mu g/mL, respectively). In relation to influenza A virus and rabies virus, the compounds show weak antiviral activity at high concentrations (1250 mu g/mL), i.e. show no selective effect on the reproduction of these viruses.