ZnO-nanocatalyst Promoted the Production of Imidazole Derivatives via four-component Reaction of Aminoacid: Study of Antioxidant and Antimicrobial Activity.

Abstract

In current research, imidazole derivatives are synthesized via a new process of four component reaction of trichloroacetonitrile, amides, alkyl bromides and amino acids catalyzed by zinc oxide nanoparticles (ZnO-NPs) as a simple and recyclable catalyst in water at room temperature. Among investigated compounds, compounds 5b have good results relative to butylated hydroxytoluene (BHT) and 2-tert-butylhydroquinone (TBHQ) as standard antioxidant. The achieved outcomes of disk diffusion experiment showed that these compounds avoided the growth of bacterial. In this research, all chemicals are purchased from Fluka (Buchs, Switzerland) and employed with any purification. For measuring infrared spectroscopy and melting point, a Shimadzu IR-460 spectrometer and Electrothermal 9100 apparatus are utilized respectively. BRUKER DRX-400 AVANCE spectrometer is used for giving the 1H, and 13CNMR spectra at 400.1 and 100 MHz respectively. For recording mass spectra, A FINNIGAN-MAT 8430 spectrometer with an ionization potential of 70 eV was utilized. The scanning electron microscopy (SEM) employing a Holland Philips XL30 microscope was used for determination of ZnO nanocomposites morphology. X-ray diffraction (XRD) analysis at room temperature using a Holland Philips Xpert X-ray powder diffractometer, with CuKα radiation (λ=0.15406 nm), with 2θ ranging from 20 to 80° was employed for characterization of crystalline structure of Fe3O4/CuO nanocomposites. Scherrer's formula; D= 0.9λ/β cosθ was employed for calculating the average crystallite size where D is the diameter of the nanoparticles, λ (CuKα) =1.5406 Å and β is the fullwidth at half-maximum of the diffraction lines. A general way to prepare of compounds 5 The trichloroacetonitrile 1 (2 mmol) and amides 2 (2 mmol) mixed with ZnO-NPs (10 mol%) in water (5 mL). after 45 min amino acids 3 (2 mmol) was added to previous mixture at room temperature. After 30 min α-haloketones 4 (2 mmol) was added to mixture and stirred for 3 h. After 3 h, the reaction is completed and TLC confirms progress of the reaction. At last, the solid residue was collected by filtration and cleaned with EtOAC to removing ZnO-NPs and after evaporating solvent and washing solid with Et2O compounds 5 afforded as pure product. Without employing catalyst, these reactions have low yield and busy mixture. The synthesis of compound 5a as sample reaction and displayed the ZnO nanoparticles (10 mol%) is the best catalyst for sample reaction and H2O is the very better than other solvent in sample raection. Structures of 5 are confirmed by IR, 1H NMR, 13C NMR mass spectra. In summary, imdazole derivatives were produced in excellent yield from the reaction of trichloroacetonitrile, amides, alkyl bromides and amino acids using ZnO-NPs in water at room temperature. In addition, the power of synthesized imidazole as antioxidant was determined by radical trapping of DPPH and power of reducing ferric analyzes. The tested imidazoles display good radical trapping of DPPH but exhibitted moderate FRAP relative to BHT and TBHQ as synthetic antioxidants.The outcomes of disk diffusion experiment exhibite that synthesized imidazole avoided the bacterial growth. The superiorities of this procedure are environmental, high yield of product and low amounts of catalyst and short time of reaction.