Synthesis, structure, and biological activity of sodium, zinc, and magnesium mono- and bis-1-alkoxy-4-(2′-naphthyl)-1,4-dioxo-2-buten-2-olates

The search for new biologically active compounds is a key area of chemical science. Therefore, the synthesis of compounds with a potentially bactericidal effect seems relevant. In order to extend the range of biologically active substances, the synthesis of sodium 4-(2’-naphthyl)-1,4-dioxo-1-ethoxy-2-buten-2-olate and sodium 1-butoxy-4-(2´-naphthyl)-1,4-dioxo-2-buten-2-olate was carried out by Claisen condensation of equimolar amounts of 2-acetonaphtone and dialkyloxalates in a non-polar medium in the presence of sodium as a condensing agent. Bidentate mononuclear metal chelates were obtained by the metal exchange reaction of sodium oxoenolates with Zn(II) and Mg(II) salts. The structure of the synthesized compounds was confirmed by infrared spectroscopy, ( 1 Н, 13 С) nuclear magnetic resonance spectroscopy, and mass spectrometry. The infrared spectra of solid samples of sodium oxoenolates and metal complexes contain bands of stretching vibrations of ester carbonyl groups, skeletal vibrations of aromatic rings, as well as “ether” bands due to vibrations of C–O–C bonds. The 1 Н and 13 С nuclear magnetic resonance spectra recorded in CDCl 3 and Dimethyl sulfoxide-d 6 are characterized by a complete set of all expected signals with chemical shift values that are well comparable with the reference data. In the mass spectra of the analyzed compounds, recorded in an acetonitrile solution in the electrospray mode, signals of [M+H] + and [M+Na] + protonated and cationized molecules are observed. The bactericidal action of the synthesized preparations was assessed using the agar well diffusion method in combination with the serial dilution method. The biological activity of sodium 4-(2’-naphthyl)-1,4-dioxo-1-ethoxy-2-buten-2-olate against Pseudomonas Aeruginosa and Staphylococcus Aureus, as well as sodium 1-butoxy-4-(2’-naphthyl)-1,4-dioxo-2-buten-2-olate against Pseudomonas Aeruginosa, was revealed. Pronounced resistance of Salmonella spp. to the studied compounds was established.