Synthesis, crystal structures and antibacterial activities of benzohydrazone derivatives from 4-diethylaminosalicylaldehyde

Abstract

A series of three new benzohydrazone compounds, C18H 21N3O3 (1), C19H23N 3O3 (2), and C18H20ClN 3O2 (3), derived from the condensation of 4-diethylaminosalicylaldehyde with 2-hydroxybenzohydrazide, 4- methoxybenzohydrazide, and 4-chlorobenzohydrazide, respectively, in methanol, were prepared. The compounds were characterized by elemental analysis, IR spectra, 1H NMR spectra, and single crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic space group P21 with unit cell dimensions a = 6.2656(6) Å, b = 21.873(2) Å, c = 6.6362(7) Å, Β = 114.025(2)°, V = 830.70(15)Å3, Z = 2, R 1 = 0.0323 and wR2 = 0.0784. Compound 2 crystallizes in the monoclinic space group P21/c with unit cell dimensions a = 13.8966(17) Å, b = 13.1402(15) Å, c = 9.8043(12) A, Β = 90.768(2)°, V = 1790.1(4) Å3, Z = 4, R1 = 0.0670 and wR2 = 0.1671. Compound 3 crystallizes in the triclinic space group P-1 with unit cell dimensions a = 9.884(2) Å, b = 11.781(3) Å, c = 15.990(4) Å, Β = 95.916(5)°, α = 99.520(5)°, β = 104.147(4)°,V = 1760.5(7) Å3, Z = 4, R1 = 0.0698 and wR 2 = 0.1250. Crystal structures of the compounds are stabilized by hydrogen bonds and stacking interactions. The preliminary antibacterial tests against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Candida albicans were assayed.