Azo Derivatives Research Articles

Synthesis and characterization of azobenzene derivatives and azobenzene-imidazolium conjugates with selective antimicrobial potential

Five new non-fluorinated and fluorinated azo derivatives, as well as a new series containing five azo-imidazolium conjugates of varying alkyl chain length in the imidazolium head group were prepared and characterized using FTIR and NMR spectroscopy, and elemental microanalysis. Antimicrobial activities of these compounds against pathogenic Gram positive bacterium Staphylococcus aureus and Gram negative bacteria Escherichia coli, Salmonella enterica serovar Typhimurium, as well as yeasts Candida albicans and Saccharomyces cerevisiae were evaluated using the disc diffusion method. The azo derivatives and their imidazolium conjugates were selectively active against the tested microorganisms with zone of inhibition diameters ranging from 10mm-21mm. Their biological efficacy was dependent on the chain length and level of fluorine substitution. The presence of long alkyl chains is essential for the azo derivatives to exhibit microbial efficacy. Active azo-imidazolium conjugates on Staphylococcus aureus contained 16 and 18 carbons in the alkyl chains while Gram negative strains exhibited a cut-off effect at chain length C16. Difference in antimicrobial behavior of the azo derivatives could be due to the different cell wall between the Gram positive and negative bacteria. Fluorination had no effect on the activity against E. coli and Salmonella. However, a clear correlation between the level of fluorine substitution and the antimicrobial activity against Staphylococcus aureus, Candida albicans and Saccharomyces cerevisiae was observed.

Ru x Pd y Alloy Nanoparticles Uniformly Anchored on Reduced Graphene Oxide Nanosheets (Ru x Pd y @rGO): A Recyclable Catalyst.

In this work, RuxPdy alloy nanoparticles were uniformly decorated on a two-dimensional reduced graphene oxide (rGO) sheet by an in situ chemical co-reduction process. The resulting products were characterized by various physiochemical techniques such as X-ray diffraction, Raman spectroscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma atomic absorption spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. Further, the synthesized RuxPdy@rGO nanocomposites have been employed as a heterogeneous catalyst for three different catalytic reactions: (1) dehydrogenation of aqueous ammonia borane (AB); (2) hydrogenation of aromatic nitro compounds using ammonia borane as the hydrogen source, and (3) for the synthesis of aromatic azo derivatives. The present work illustrates the sustainable anchoring of metal nanoparticles over the surface of rGO nanosheets, which could be used for multifarious catalytic reactions.

Diaryl azo derivatives as anti-diabetic and antimicrobial agents: synthesis, in vitro, kinetic and docking studies

In the present study, a series of azo derivatives (TR-1 to TR-9) have been synthesised via the diazo-coupling approach between substituted aromatic amines with phenol or naphthol derivatives. The compounds were evaluated for their therapeutic applications against alpha-glucosidase (anti-diabetic) and pathogenic bacterial strains E. coli (gram-negative), S. aureus (gram-positive), S. aureus (gram-positive) drug-resistant strain, P. aeruginosa (gram-negative), P. aeruginosa (gram-negative) drug-resistant strain and P. vulgaris (gram-negative). The IC50 (µg/mL) of TR-1 was found to be most effective (15.70 ± 1.3 µg/mL) compared to the reference drug acarbose (21.59 ± 1.5 µg/mL), hence, it was further selected for the kinetic studies in order to illustrate the mechanism of inhibition. The enzyme inhibitory kinetics and mode of binding for the most active inhibitor (TR-1) was performed which showed that the compound is a non-competitive inhibitor and effectively inhibits the target enzyme by binding to its binuclear active site reversibly.

Synthesis of new azo dye compounds derived from 2-aminobenzothiazole and study their biological activity

In this work, new 2-amino benzothiazole (W1) were synthesized from the reaction between aniline substituted with potassium thiocyanate in presence of broom. (W1) reaction with phenol substituted to give azo dyes compound (W2-W5). Polyacrylic acid was converted into poly acryloyl chloride by reaction poly acrylic acid with thionyl chloride was dissolved in acetonitrile with reaction different organic compounds. (W1-9) characterized were using (IR) and (HNMR-CNMR-CHN–TLC) techniques and the analysis revealed biological activity for chemical compounds at three concentrations (0.01, 0.001, 0.0001) mg/ml. (MIC) was calculated using standard drugs as a comparison. The findings revealed that azo derivatives outperformed medication in inhibiting the growth of gram negative & positive bacteria.

Anticancer activity of novel Schiff bases and azo dyes derived from 3-amino-4-hydroxy-2H-pyrano[3,2-c]quinoline-2,5(6H)-dione

Abstract New Schiff bases and azo dyes derivatives have been synthesized via appropriate conventional methods using pyranoquinolinone as a starting material. The compounds obtained were characterized by spectral analysis and evaluated for anticancer activity in several human tumor cell lines: MCF-7 breast cancer, HepG2 liver cancer and HCT-116 colon carcinoma. 5-fluorouracil was used as a reference drug. The in vitro cytotoxicity screening results revealed that all tested compounds showed promising activity against MCF-7 cells. In particular, compounds 6a, 6b, and 7b showed excellent activity against the three human tumor cell lines. Structure-activity relationship studies indicated that the azo derivative with a trifluoromethoxy group (compound 7b) was the most potent candidate against the three human tumor cell lines (IC50, 1.82-8.06 μg/mL). Our findings highlight pyranoquinolinone analogues as a promising class of compounds for new anticancer therapies.

Synthesis, spectroscopic characterization, dyeing performance and corrosion inhibition study of transition metal complexes of a novel azo derivative formed from 2-aminothiophene

Abstract A novel bi-heterocyclic azo derivative is synthesized by the diazo-coupling reaction of 2-amino-3-carbethoxy-4,5-dimethylthiophene and 2-amino-4-phenylthiazole and its ligational behaviour towards Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) salts is investigated. The complexes are characterized on the basis of elemental analyses, molar conductance, magnetic susceptibility measurements, UV-Visible, IR and 1H NMR spectral data. Spectral data have indicated that the ligand is coordinated to the metal ion in a neutral bidentate manner. On the basis of electronic spectral data and magnetic susceptibility measurements, suitable geometry is proposed for each complex. Thermogravimetric studies of copper(II) complex are used to characterize the complex. The dyeing performance of the azo derivative and its metal complexes is examined on silk fabric. The corrosion inhibition efficiency of the ligand and its metal complex in 0.5 M H2SO4 for mild steel coupons is monitored by weight-loss and open circuit potential measurements .

Comparative in vitro and DFT antioxidant studies of phenolic group substituted pyridine-based azo derivatives

Two azo compounds 2-(3-pyridylazo)-3,5-dihydroxybenzoic acid (PAB) and 4-(3-pyridylazo)resorcinol (PAR) thought to have the potential to be used as antioxidants were designed, synthesized and antioxidant activities were investigated both in vitro and in silico. The synthesized compounds were characterized by 1H-NMR, 13C-NMR, FT-IR, UV-Vis and mass spectra. The molecular geometry and vibrational frequency calculations of the synthesized compounds in ground state were performed by the density functional theory (DFT) employing B3LYP level with the 6-311 G(d,p) basis set. The gauge independent atomic orbital (GIAO) method was used to determine the chemical shift values of 1H-NMR and 13C-NMR. HOMO–LUMO calculations were carried out by time-dependent DFT (TD-DFT) approach. Computational spectroscopic data of the synthesized compounds are fully compatible with experimental ones. The antioxidant activities of the PAB and PAR were investigated by using DPPH assay. It was determined that the PAB molecule showed better antioxidant activity than PAR and, butylated hydroxytoluene (BHT) which is the standard antioxidant. In addition, the thermodynamic stability parameters obtained with the help of DFT calculations were found to be quite compatible with the antioxidant capacity sequence derived from the DPPH assay. Highlights Two pyridine derivative azo compounds were synthesized and evaluated for its antioxidant activity Molecular geometry and spectroscopic properties of the molecules were calculated in vitro and in silico antioxidant activities were investigated by DPPH free radical scavenging assay The PAB molecule showed better antioxidant activity than BHT Communicated by Ramaswamy H. Sarma

Spectrophotometric Determination of Dopamine in Bulk and Dosage Forms Using 2,4-Dinitrophenylhydrazine.

Dopamine (DA) hydrochloride is a sympathomimetic agent used therapeutically for the correction of hemodynamic disorders associated with shock episodes. Although several analytical methods have been described, a spectroscopic assay of DA after chemical derivatization with 2,4-dinitrophenylhydrazine (DNP) is still unexamined. Therefore, the optimization of the reaction parameters and validation of developed method were required. The method is based on coupling of DA as a phenolic compound with a diazonium salt to produce an intensely colored azo derivative. DNP was oxidized with potassium periodate to produce a diazonium salt that coupled with DA in basic media. The experimental parameters were then optimized. The developed method was validated according to International Conference on Harmonisation Guidelines and was applied to dosage forms. The results were compared with the data of a reference method. The method was linear in a concentration range between 5 and 50 μg/mL. The regression line equation was Y=0.042±0.0003X+0.0672±0.0015 with a regression coefficient of 0.9944 (n=5). The limit of detection and limit of quantification were 0.32 and 0.97 μg/mL, respectively. The precision was satisfactory; the percentage relative standard deviation did not exceed 2%. The average values of the recovery study were in the range 98.90- 100.40±0.31-1.21%. The developed method was applied successfully for the determination of DA in injection and infusion fluid. The method is accurate, sensitive, and practical for DA analysis in quality control laboratories.

Synthesis, Characterization and Theoretical Calculations of a Novel Azo Derivative with In Vitro and In Silico Biological Studies

An azo molecule, 2,2-dimethyl-5-(m-tolyldiazenyl)-1,3-dioxane-4,6-dione (DTDD), was designed, synthesized and evaluated for its antibacterial potential. The structure of the DTDD was confirmed by 1H-NMR, 13C-NMR, FT-IR and UV–Vis spectra. The molecular geometry and vibrational frequency calculations of the DTDD in the ground state were performed by the density functional theory (DFT) employing the B3LYP level with the 6-311G(d,p) basis set. 1H-NMR and 13C-NMR chemical shifts were calculated by using the gauge independent atomic orbital (GIAO) method. Electronic property and HOMO–LUMO calculations were carried out by a time-dependent DFT (TD-DFT) approach. The calculated spectroscopic values for the DTDD were in very good agreement with experimental ones. Besides, in vitro antibacterial activity of the DTDD was studied against five different bacterial cultures. DTDD showed antibacterial activity with an MIC range of 62.5–500 µg/mL. The best antibacterial activity was found with 62.5 µg/mL against S. aureus. Additionally, molecular docking studies against β-ketoacyl-acyl carrier protein synthase III (KAS III) and lipoteichoic acid synthase (LtaS) were performed. According to the binding energy (− 7.67 kcal/mol) and full fitness score (− 2391.78), the ligand had a better orientation with LtaS. Druglikeness and ADME parameters were also calculated and the TPSA value was found to be 76.99 A2. The calculated values showed that DTDD had good oral drug candidate properties.

Rational synthesis and characterization of medicinal phenyl diazenyl-3-hydroxy-1h-inden-1-one azo derivatives and their metal complexes

The emergence of resistance to the major classes of antibacterial drug is recognized as serious health concern. So the development of new and more effective antimicrobial agents are necessary for human health. In this study a new series of azo based 1,3-indandion derivatives (4-MHPD, 2-BrHPD, 3-BrHPD 2-IHPD and 4-IHPD) was synthesized by reacting 1,3-indandion with various anilines (4- methyl aniline, 2-bromo aniline, 2-bromo aniline 2-isopropyl aniline and 4-isopropyl aniline) by diazotization, and metal complexes (Cu2+, Zn2+, Ni2+ and Mn2+) in mild, efficient, and convenient method with good yields in less time. All the newly synthesized compounds were characterized by IR, NMR (1H, &13C), UV/VIS and mass spectrometry. The appearance of -N=N- peak at 1400–1500 cm−1 with disappearance of NH2 peak at 3500 cm−1 in FTIR spectra and chemical shift at 11.00–13.00 ppm for -OH protons confirmed the synthesis of new azo derivatives. The appearance of C-OH sharp peak at 180–190 ppm and appearance of molecular ion peaks at 264 m/z, 329 m/z and 292 m/z and respectively further gives strong indication for the synthesis of proposed azo derivatives. Synthesized compounds were also screened for their antioxidant, antibacterial, antifungal, chymotrypsin and tyrosinase inhibition activities. Result have shown that among synthesized compounds, 2-IHPD, 2-BrHPD, 4-MHPD and their metal complexes with Cu2+ and Zn2+ have shown greater inhibitions against standard drugs. Furthermore structure activity and metal complexes versus ligands activity relationship were also explored in this study which revealed that presence of electron donating, halogen group and presence of transition metals enhanced the biological activities of tested compounds.

Sulfate radical-based oxidation of the aminopyralid and picloram herbicides: The role of amino group on pyridine ring

The widespread utilization of pesticides has attracted increasing attention to their environmental impacts and effective removal strategies. In the present study, the degradation of herbicides picloram (PCLO) and aminopyralid (AMP) with similar structures were investigated systematically by thermo activated persulfate. Overweight SO4•− was determined to be the predominant oxidizing species by quenching experiment. Obtained by laser-flash photolysis (LFP), reaction rate constants of SO4•− towards AMP and PCLO were determined at 1.56 × 109 M−1s−1 and 1.21 × 109 M−1s−1, respectively. Product analysis revealed that both substances underwent similar oxidation paths, namely, successive oxidation on pyridine ring and formation of coupling-products as well as further hydroxylation and decarboxylation. Amino group on the pyridine ring was identified as the main reactive site, which was further confirmed by DFT calculation. It was susceptible attacked by SO4•− to form deamination, nitration, and self-coupling products. These couples could be further oxidatively dehydrated to form azo and a series of azo derivatives. EOCSAR program predicted significant hazards on aquatic species during the formation of these couplings and azo derivatives. Our work emphasized the potential ability and toxicity of contaminates to produce azo substances in the presence of amino groups on the pyridine ring.

Antiviral evaluation of bioactive azo derivatives to treat endemic poultry viruses

Antiviral evaluation of bioactive azo derivatives to treat endemic poultry viruses

An experimental and DFT study on novel dyes incorporated with natural dyes on titanium dioxide (TiO2) towards solar cell application

Titanium dioxide (TiO2) thin films were deposited on fluorine tin oxide (FTO) coated glass substrate using spin-coating techniques and as-deposited films were sensitized with various dyes. A series of azo derivatives (2, 5a-b) having different structures were successfully prepared through the process of the azo coupling reaction. KAZO 6 was successfully synthesized by esterification of kojic acid obtained from sago waste with azo 5a. These azo dye were examined using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) to obtain the vertical excitation, electron distribution, energy levels, band gap, and light-harvesting efficiency in the ground and excited state. The obtained values exhibited a good correlation with the experimental values. Efficiency enhancement was reported by the incorporation of KAZO 6 with curcumin extracted from turmeric. Spectroscopy and optical properties of synthesized dyes were characterized using CHNS elemental analysis, FTIR, 1H NMR, 13C NMR, and UV–Vis spectroscopies. KAZO 6 displayed an efficiency of 1.59% compared to azo derivatives 0.13–1.12%. The efficiency of KAZO 6 enhanced from 1.59 to 1.74% with the incorporation of turmeric dye.

Experimental data of CaTiO3 photocatalyst for degradation of organic pollutants (Brilliant green dye) - Green synthesis, characterization and kinetic study.

The data presented here focuses on the physicochemical characterization of perovskite CaTiO3 nanoparticles (orthorhombic) as photocatalyts and the kinetic study of their photodegradation performance toward organic pollutant, i.e. brilliant green (BG) which is azo derivatives dye. The CaTiO3 nanoparticles was synthesized using chicken eggshell-derived CaCO3 and anatase TiO2 with molar ratio of (1:1), (1:3), (2:5), and (2:7). The physical and microstructural properties of CaTiO3 were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), Fourier Transform Infrared (FTIR) and UV/vis spectrometer. The effect of initial dye concentration, catalyst composition, and catalyst dosage on the adsorption mechanism of dye on CaTiO3 was investigated in jacketed photoreactor under UV irradiation. The analysis reveals that BG molecules are efficiently chemisorbed, as indicated by pseudo first order kinetic, and degraded within 120 min. Considering the low-cost preparation process and high photocatalytic performance, the resultant CaTiO3 can further be used as an efficient photocatalyst for organic pollutant removal from aqueous and industrial wastewater.

Synthesis, characterization, pharmacological evaluation and molecular docking studies of benzothiazole azo derivatives

A series of novel benzothiazole based azo dyes were synthesized and fully characterized by using different analytical techniques. The antioxidant activity of synthesized azo dyes was studied with the DPPH, hydrogen peroxide, metal chelating and nitric oxide radical methods and compared with the known antioxidant ascorbic acid. Further, the anticancer properties of synthesized azo dyes were carried out against breast cancer (MCF-7) cell lines by MTT assay and results revealed that the synthesized compounds exhibited good anticancer property in micro-molar range. Additionally, the anti-inflammatory activities of target compounds were also investigated by protein denaturation method and were found to have effective anti-inflammatory property. In order to predict the binding modes and binding affinity of synthesized compounds, they were docked into the active sites of protein B-cell lymphoma-extra-large (Bcl-xL) to predict their anticancer property. The synthesized compounds were found to have good affinity for B-cell lymphoma-extra-large (Bcl-xL). A good correlation was found between in-silico docking analysis and in biological screening of all synthesized azo dyes with less binding energies and higher inhibition constants value against the target protein.

Tuneable Copper Catalysed Transfer Hydrogenation of Nitrobenzenes to Aniline or Azo Derivatives

AbstractA highly versatile and flexible copper nanoparticle (Cu(0) NPs) catalytic system has been developed for the controlled and selective transfer hydrogenation of nitroarene.Interestingly, the final catalytic product is strongly dependent on the nature of the hydrogen donor source. The yield of nitrobenzene reduction to aniline increased from 20% to an almost quantitative yield over a range of alcohols, diols and aminoalcohols. In glycerol at 130 °C aniline was isolated in 93% yield. In ethanolamine, the reaction was conveniently performed at a lower temperature (55 °C) and gave selectively substituted azobenzene (92% yield). Experimental studies provide support for a reaction pathway in which the Cu(0) NPs catalysed transfer hydrogenation of nitrobenzene to aniline proceeds via the condensation route. The high chemoselectivity of both protocols has been proved in experiments on a panel of variously substituted nitroarenes. Enabling technologies, microwaves and ultrasound, used both separately and in combination, have successfully increased the reaction rate and reaction yield.magnified image

Photoacoustic effect and controlled release of azo and Schiff base derivatives modified by click reagents under the NIR light

PurposeThis study aims to develop a new kind of functional low molecular weight organic dyes, which is highly efficient, meanwhile inexpensive and easily prepared and modified and can be used in photoacoustic (PA) imaging and photothermal therapy (PTT). To further realize the release of molecules under the biomedical condition, the releasing efficiency of micellar nanoparticles under different stimuli were represented.Design/methodology/approachA class of azo and Schiff base derivatives with different click reagents were characterized by PA imaging and photothermal (PT) experiments. The molecule with best PT effect was loaded into a temperature-stimuli-sensitive amphiphilic block copolymer which demonstrated the capability of releasing the polymers under the near-infrared (NIR) light of 650 nm.FindingsThe PA and PT effects of a series of azo and Schiff base derivatives with different click reagents were characterized. Introducing the click reagent F4-TCNQ can result in red shift of peaks of PA intensity. Stimulated with 650 nm laser irradiation, the polymer processed higher release rate than being stimulated by temperature stimuli.Practical implicationsThis paper not only guides the design of NIR dyes with good PA intensity but also provides a method which has great potential for the application of NIR photothermal dyes in the field of biotechnology for controlled release.Originality/valueThis paper uses click reagents to modify azo and Schiff derivatives and an amphiphilic block copolymer under NIR light to realize controlled release.

Free‐radical polymerization upon near‐infrared light irradiation, merging photochemical and photothermal initiating methods

ABSTRACTPolymerization of (meth)acrylate resins upon near‐infrared (NIR) light remains a huge challenge. In this study, a new photoinduced method of polymerization of methacrylic monomers is presented, originally merging a photochemical and a photothermal pathway. A four‐component system is proposed comprising an NIR dye combined with an iodonium salt, a phosphine, and a thermal initiator. A selection of dyes is suggested regarding electron transfer properties and/or light‐to‐heat conversion abilities. Several thermal initiators are studied: an alkoxyamine (BlocBuilder MA), an azo derivative, and a peroxide. For the first time, an NIR absorbing dye is used in photopolymerization using both its capacities of light‐to‐heat conversion and its ability to initiate an electron transfer reaction. Three wavelengths of irradiation will be presented here: 785, 940, and 1064 nm. These long wavelengths are challenging because the energy of photons is extremely low but these wavelengths offer significant advantages in term of light penetration (e.g., for the access to composites through photopolymerization processes). The different systems presented here exhibit high and rapid conversions of methacrylate functions. The underlying chemical mechanism will be fully depicted by real‐time Fourier transform infrared spectroscopy and thermal imaging measurements. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 300–308

Bending control of liquid-crystal elastomers based on doped azo derivatives synthesized via controlled gradient polymerization

Bending control of liquid-crystal elastomers based on doped azo derivatives synthesized via controlled gradient polymerization

Ultrasound-degradable serum albumin nanoplatform for in situ controlled drug release.

In this work, bovine serum albumin-based nanoparticles, BSA-ACVA-DOX NPs, were fabricated for ultrasound-driven drug release, and exhibited excellent tissue penetration. Moreover, a pulsatile release of DOX in vivo could be programmed by in vitro (i.e., remotely) switching the ultrasound on and off.