Preparation, crystal structure and antibacterial activity of condensation products of usnic acid and acyl hydrazides
AuthorsSladić, Dušan M.
Bogdanović, Goran A.
MetadataShow full item record
Three condensation products of usnic acid with the hydrazides of alpha-naphthoic, caprylic, and oxamic acids, respectively, have been prepared and characterized by spectrometric methods. A reassignment of the C-13-NMR spectral data of usnic acid has been done. The crystal structure of usnic acid 11-[(1-naphthoyl)hydrazone] ethanol solvate (1:1) has been determined. This substance crystallizes in the monoclinic crystal system, the space group P2(1), with the unit cell dimensiones a=7.7365(7) Angstrom, b = 19.632(2) Angstrom, c = 9.4150(15) Angstrom, beta = 108.830(11)degrees, V = 1405.0(4) Angstrom(3), and Z=2. At the end of the structure analysis R = 0.055, R-w = 0.052 and S = 0.89. The antibacterial activities of the compounds have been evaluated. The greatest activity against Staphylococcus aureus was found for usnic acid, somewhat lower for the derivatives with hydrazides of alpha-naphthoic and caprylic acid, and much lower for the derivative with semioxamazide. The activities of th...ese compounds probably depend on their lipophilicity.