New type of RNA virus replication inhibitor based on decahydro-closo-decaborate anion containing amino acid ester pendant group.

In this work, a synthetic approach to prepare an example of new class of the derivatives of the closo-decaborate anion with amino acids detached from the boron cluster by pendant group has been proposed and implemented. Compound Na2[B10H9-O(CH2)4C(O)-His-OMe] was isolated and characterized. This compound has an inorganic hydrophobic core which is the 10-vertex boron cage and the -O(CH2)4C(O)-His-OMe organic substituent. It has been shown to possess strong antiviral activity in vitro against modern strains of A/H1N1 virus at 10 and 5 µg/mL. The compound has been found to be non-cytotoxic up to 160 µg/mL. At the same time, the compound has been found to be inactive against SARS-CoV-2, indicating specific activity against RNA virus replication. Molecular docking of the target derivative of the closo-decaborate anion with a model of the transmembrane region of the M2 protein has been performed and the mechanism of its antiviral action is discussed.