In Silico Studies of 2-((2-Hydroxybenzylidene)hydrazineylidene)-2-phenylacetaldehyde Oxime

Detailed structural and computational studies of 2-((2-hydroxybenzylidene)hydrazineylidene)-2-phenylacetaldehyde oxime (1), using the DFT and molecular docking computations, are reported. The molecular structure of 1 is stabilized by a O–H⋅⋅⋅N hydrogen bond between the phenolic OH hydrogen atom and the nearest hydrazineylidene nitrogen atom, yielding a six-membered noncovalent ring, which, in turn, was found to be highly aromatic. Intermolecular O–H⋅⋅⋅N and C–H⋅⋅⋅N hydrogen bonds between molecules of 1 produce a 1D supramolecular polymeric chain of the zig-zag type. These chains are linked into a 2D supramolecular layer due to reciprocal π⋅⋅⋅π interactions formed between the phenylene and six-membered noncovalent rings. The reciprocal H⋅⋅⋅X (X = H, C, N, O) and C⋅⋅⋅Y (Y = C, N) contacts are the most prominent contributors to the crystal packing. The optimized molecule of 1 is a pronounced electrophile with the most nucleophilic sites found on the phenolic oxygen atom, oxime oxygen and nitrogen atoms, and one of the hydrazineylidene nitrogen atoms, while the oxime OH and some of the phenylene hydrogen atoms were revealed as the most eletrophilic sites. The discussed compound was found to be active against all the studied herein SARS-CoV-2 proteins. The best results were revealed against Papain-like protease (PLpro), nonstructural protein 14 (Nsp14_N7-MTase), and nonstructural protein 3 (Nsp3_range 207–379-MES), with the calculated ligand efficiency scores for complex PLpro–1 being within the recommended ranges for a Hit.