Synthesis and Antibacterial Activity of New Schiff Bases Derived from 2,3-Diaminopyridine and Their Copper(II), Iron(III), Nickel(II) and Zinc(II) Complexes
Year: 2013
Type: article
Abstract: Three new bis-condensed Schiff bases (1-3), one imidazo-pyridine (4) and twelve Schiff base metal complexes derived from 2,3diaminopyridine (DAPY) have been synthesised.The mixed Schiff bases DAPY-{ValH}{SalH} (1) and DAPY-{ValH}(DhbH2} (2) were obtained by equimolar reaction of the mono-condensed Schiff base of DAPY and o-vanillin (ValH), DAPY-{ValH}with salicylaldehyde (SalH) and 2,3-dihydroxybenzaldehyde (DhbH2), respectively.1:2 Molar condensation of DAPY with DhbH2 yielded the Schiff base (3), whereas reaction of the same reagents in a 1:0.8 mol ratio gave the imidazo-pyridine, 2-(2,3-dihydroxyphenyl)-1H-imidazo-(4,5-b)pyridine (4).The Schiff bases and Schiff base metal complexes (1600 µg cm -3 ) were screened in vitro against three bacteria (Staphylococcus aureus, Bacillus subtilis and Escherichia coli) using the diffusion method.Some of them were found to be more active than the control cetyl trimethyl ammonium bromide. KeyWords: Schiff bases, 2,3-Diaminopyridine, 2,3-Dihydroxybenzaldehyde, o-Vanillin, Salicylaldehyde, Antibacterial, Imidazo-pyridine.microbial agents 3,4,6,12 , analytical reagent 7 or electrochemical sensor 9 .In continuation of our work on Schiff bases derived from DAPY 3,4,6 we now report the synthesis of three new biscondensed Schiff bases (1-3), of which two are mixed, one imidazo-pyridine (4) and twelve transition metal (copper, iron, nickel and zinc) Schiff base complexes (1a-1d), (2a-2d) and (3a-3d). EXPERIMENTALAll chemicals (analar grade) were purchased from either Aldrich or BDH and used as received.IR spectra of the samples were recorded as KBr pellets on a FTIR Mattson 1000 spectrometer in the 4000-400 cm -1 region. 1 H and 13 C NMR spectra in DMSO-d6 were obtained from a Bruker Spectrospin 250.Magnetic susceptibilities of metal complexes were determined using a Sherwood Scientific magnetic balance.Copper, iron, nickel and zinc content were found using a Unicam 929 atomic absorption spectrometer, whereas C, H and N analyses were obtained using a LECO 932 CHNS analyzer.Melting points were measured using a Stuart Scientific melting point apparatus and were uncorrected.Mass spectra were recorded on a Fissions VG Trio 2000 mass spectrometer, University of Manchester. Preparation of Schiff bases:The mono-condensed Schiff base DAPY-{ValH} was synthesized using literature procedures 1,3 .
Source: Asian Journal of Chemistry
Institution: University of Mauritius
Language: English
Subfield: Oncology
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W4239558011