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Abstract An aromatic hydrazone derivative; namely (E)-1-(3-nitrobenzylidene)-2-(p -tolyl)hydrazine (E-NBPTH) has been synthesized by condensation of an aromatic hydrazine with an aromatic aldehyde in methanol at reflux. The molecular structure of E-NBPTH has been identified and analyzed by spectroscopic methods such as UV–vis, IR, 1H NMR and 13C NMR. The corrosion inhibition behavior of the prepared molecule in 0.5 M H 2 SO 4 was investigated by gravimetric, electrochemical and theoretical methods. According to the polarization study, the E-NBPTH acts as a mixed type of inhibitor. The adsorption of E-NBPTH on the iron surface follows the Langmuir isotherm. The optimized molecular structure and some quantum chemical parameters of the synthesized compound have been calculated using the density functional method (DFT). The results obtained from theoretical study are well support the experimental results. Graphical abstract Image 1 Highlights • New hydrazone derivative (E-NBPTH) was synthesized and characterized. • UV–Vis, IR and NMR analysis of E-NBPTH was realized. • Anti-corrosive activity of E-NBPTH was experimentally evaluated. • DFT method was used to determine the quantum parameters of the studied derivative. • Molecular dynamic simulations have been performed. [ABSTRACT FROM AUTHOR]

Abstract Tow new α-aminophosphonic acids, Ethyl hydrogen [(2-methoxyphenyl)(methylamino) methyl]phosphonate (2-EHMAP) and Ethyl hydrogen [(3-methoxyphenyl)(methylamino) methyl]phosphonate (3-EHMAP) were synthesized by the reaction between Methylamine, 2- or 3-Methoxybenzaldehyde and Diethylphosphite in THF solution with FeCl 3. The structures of the title compounds were determined by UV–Vis, FT-IR, 1H, 13C, 31P NMR and MS spectra and confirmed by centesimal analysis. Their inhibition efficiency on the corrosion of mild steel in 1 M HCl and 0.5 M H 2 SO 4 solutions was studied by weight loss, polarization curves and electrochemical impedance spectroscopy (EIS). The surface morphology of XC38 simple was studied by scanning electron microscopy (SEM) and Atomic Force Microscopy (AFM). The experimental results show that both molecules are mixed inhibitors and that their adsorptions on the surface of mild steel obey the Langmuir isotherm and that the 2-EHMAP exhibit better inhibition efficiency. Quantum chemical calculations were performed by using DFT to study the influence of molecular structure on the inhibition efficiency; theoretical findings are in good accord with the experimental observations. Graphical abstract Image Highlights • Synthesis and characteristic of two ethyl hydrogen phosphonate, 2-EHMAP and 3-EHMAP. • Inhibitory potency of both molecules against corrosion of steel in acidic mediums. • Effect of the presence of inhibitors on the surface morphology of XC38 mild steel. • The 2-EHMAP inhibitor is more effective than 3-EHMAP in both media. • The effect of molecular structure on the inhibition efficiency was performed by DFT. [ABSTRACT FROM AUTHOR]

Two new categories of α-aminophosphonates molecules were synthesized and characterized by UV-Vis, IR, and NMR. Their spectral properties show a perfect convergence. Their biological activities were evaluated. Molecules 1a , 2a , and 1d present a greater antioxidant potential than BHT and vitamin C. The best anti-inflammatory activity is shown by the 2b molecule and that of 1a , 2a , and 2c molecules are closely comparable to that of diclofenac. The antibacterial activity of the synthesized compounds is significantly higher than the antibiotic amoxicillin. The hemolysis rate HR of compounds 1b , 1c , 2b , and 2c was lower than 5%. [ABSTRACT FROM AUTHOR]

New di-, tri-, and tetraphosphonic acids were synthesized starting from four o-hydroxymethyl phenol derivatives and obtained in three steps in good overall yield. The phosphonic acids were isolated and purified using semi-preparative C18 HPLC column. The new compounds were characterized using different spectroscopic methods (1H, 13C, and 31P NMR; ESI MS; and MSn, IR). GRAPHICAL ABSTRACT[image omitted] [ABSTRACT FROM AUTHOR]

• Imine and α-aminophosphonate derivatives were synthesized and characterized. • The Antioxidant activity was evaluated using DPPH, FRAP and β-carotene assays. • The synthesized compounds were found good antioxidant activities. • The phosphonate derivative has the greatest antioxidant activity. [Display omitted] New molecule α-aminophosphonate namely (2-hydroxynaphthalen-1-yl) methyl 2-hydroxyphenyl amino phosphonic acid (HMHP) was synthesized by condensation based on 2-amino phenol and 2-hydroxy naphthaldehyde. During the reaction, imine intermediate namely 2-hydroxyphenyl imino naphthalen-2-ol (HIN) was formed before adding acid phosphorous to the reaction mixture. It can be confirmed the concept of Kabachinik-Fields reaction, which it's perform the attachment of phosphorus atom to the carbon atom of imine function. Both compounds were identified using IR, 1H, 13C and 31P NMR spectroscopic techniques. The evaluation of the antioxidant activity of HMHP and HIN was investigated by utilizing several in vitro assays: scavenging activity against DPPH radical and H 2 O 2 non radical, β-carotene/linoleic acid against linoleic peroxidation, reducing power against ferric oxidation and phosphomolybdate (TAC) against molybdate ion oxidation. Results indicate that HMHP reflects greater antioxidant potency compared to HIN in most tests, where it is apt to offer the hydrogen radical very well at IC 50 (37.64 ± 1.43) in DPPH test. For the other tests the inhibition percent at 50 % are relatively closed between them. Except the H 2 O 2 scavenging, while HIN exhibited excellent activity at IC 50 (24.7306 ± 0.71785). The quantum chemical calculations were performed using density functional theory (DFT) to study the effects of the transfer electronic and proton transfer on the antioxidant activities of the synthesized compounds. Also, theoretical FT-IR was calculated. The experimental results are in comfort with those calculated theoretically. [ABSTRACT FROM AUTHOR]

Four azoimine quinoline derivatives namely (1Z)-N'-(4-fluorophenyl)-2-oxo-N-quinolin-8-ylpropanehydrazonamide (H 2 L-F) ,(1Z)-2-oxo-N′-phenyl-N-quinolin-8-ylpropane hydrazonamide (H 2 L-H) ,(1Z)-N'-(4-nitrophenyl)-2-oxo-N-quinolin-8-ylpropane hydrazonamide (H 2 L-NO 2) and (1Z)-N'-(4-bromophenyl)-2-oxo-N-quinolin-8-ylpropane hydrazonamide (H 2 L-Br) were synthesized and evaluated for their biological activities. At very low concentrations, the four compounds showed a greater antioxidant potential than that of ascorbic acid. The results of the antimicrobial screening indicate that all derivatives have a variable activity against the investigated species, bacteria and fungi. The anti-inflammatory activity of the compounds was found to be in the range of 55–80%. The binding interaction of these molecules with DNA and bovine serum albumin (BSA) was investigated by UV–visible and cyclic voltammetry. The DNA binding study revealed that all the compounds are strongly bound to DNA via intercalation in a spontaneous manner. It was also found that the investigated azoimine quinolines are interacted to BSA with a static quenching process. The choice of these molecules was based on simple synthesis processes, better yield, moderate toxicity, and low cost. Image 1 • New azoimine quinoline H 2 L-F derivative was synthesized. • All compounds could be considered as potential antioxidants. • H 2 L-Br and H 2 L-F show the best anti-inflammatory activity. • The compounds are efficient DNA binders. • Compounds are interacted to BSA with a static quenching process. [ABSTRACT FROM AUTHOR]

In this work, we have synthesized three diethyl (phenylamino) methyl) phosphonate derivatives: Diethyl(phenyl(phenylamino)methyl)phosphonate(DEPAMP), Diethyl(((2-meth oxyphenyl(phenylamino)methyl)phosphonate (o-DEPAMP), Diethyl(((4-methoxy phenyl(phe nylamino)methyl)phosphonate (p-DEPAMP), whose the yields were 92%, 86% and 88% respectively. After confirmation of their structures by UV–Vis, FT-IR and NMR spectroscopic methods, the synthesized compounds were investigated as corrosion inhibitors of XC48 carbon steel in 1 mol L−1 HCl medium. The results show that the Para position is a better inhibitor in 10−3 mol L−1. Atomic Force Microscopy (AFM) was required for metallic surface characterization and the quantum chemical parameters were calculated using the Density Functional Theory (DFT) method. The adsorption energies of the inhibitors on Fe (110) surface in gas and aqueous phases were premeditated adopting the Molecular Dynamics Simulation (MDS) method. This study described the successful performance of these compounds in corrosion using weight loss measurements, Potentiodynamic Polarization and Electrochemical Impedance Spectroscopy (EIS), and discusses the correlation between experimental and theoretical, presumed DFT and MDS finding. The adsorption studies on surface were in agreement with the Langmuir adsorption isotherm model. The effects of position of OCH 3 group located at ortho and para or without in chemical structure of aminophosphonates on the corrosion inhibition efficiencies of the compounds were also investigated. Image 1 • Synthesis and structural studies of three α-aminophosphonate derivatives. • The compounds (DEPAMP), (o-DEPAMP), (p-DEPAMP) are effective corrosion inhibitors. • High E HOMO and low E LUMO with a small Δ Ε gap confirmed a good inhibition efficiency. • The inhibition efficiency of the best inhibitor p-DEPAMP reached 98%. • All inhibitors can be adsorbed on Fe (110) with a high adsorption energy. [ABSTRACT FROM AUTHOR]

• A new α-Hydrazinophosphonic acid (HDZPA) was synthesized and characterized. • Optimization and vibrational study of HDZPA were performed using B3LYP/6–31 G (d,p). • MEP map elucidates that the nucleophilic zones are situated on the oxygen atoms. • The reactivity of HDZPA was evaluated using frontier orbitals studies. • The inhibition of SARS-CoV-2 main protease and RNA dependent RNA polymerase by HDZPA was predicted. A new α-Hydrazinophosphonic acid (HDZPA) has been synthesized and its molecular structure was determined using spectroscopic methods. The Density Functional Theory (DFT) at the B3LYP/6–31 G (d,p) level was utilized to determine the electronic properties, vibrational modes and active sites of the examined molecule. In this context, some quantum chemical parameters have been calculated in order to discuss the reactivity of the studied molecule. Also, the inhibition activity of the investigated α-Hydrazinophosphonic acid for SARS-CoV-2 main protease (Mpro) and RNA dependent RNA polymerase (RdRp) has been predicted using in silico docking. [Display omitted] [ABSTRACT FROM AUTHOR]

• Three aromatic hydrazones were prepared and characterized. • Spectral and structural properties of the prepared derivatives were studied. • Experimental results have been correlated by DFT method at B3LYP/6–311++ G (d,p). • The tested hydrazones are effective antioxidant and antibacterial agents. • The in silico study of the inhibition of SARS-CoV-2 main protease has been performed. Three new hydrazones namely: (2E)-1-(4-methylphenyl-2-[(thiophen -2- yl) methylidene ]hydrazine (HZ-1), (2E)-1-(4-methylphenyl)-2-[(thiophen -3 yl) methylidene ]hydrazine (HZ-2) and (1E)-1[(furan -2- yl) methylidene ]-2-(4methylphenyl)hydrazine (HZ-3) have been synthesized by reacting (4-methylphenyl)hydrazine with three heterocyclic aldehydes: 2-thiophenecarboxaldehyde, 3-thiophenecarboxaldehyde and 2-furaldehyde in ethanol at reflux 78 °C. The structures of these compounds were confirmed by spectroscopic and physicochemical methods such as UV–Vis, IR, melting point, 1H NMR and 13C NMR spectra. Their antioxidant activity was evaluated using DPPH, ABTS, FRAP, CUPRAC and phenanthroline assays. The obtained results indicate that the title molecules exhibit excellent activity better and comparable as standards BHT, BHA and ascorbic acid. Also, the synthesized compounds show a good antibacterial activity against two such: P. aeruginosa and B. subtilis. In addition, the density functional theory (DFT) is used to calculate the optimized molecular structures, electronic and vibrational spectra, reactivity, stability and some quantum chemical parameters of the synthesized molecules. The obtained theoretical results are in good agreement with the experimental results. Finally, in silico predictions of ADME-T and pharmacokinetic parameters indicated that these compounds should have good oral bioavailability. Also, the molecular docking has been used to predict the inhibitory activity of SARS-CoV-2 main protease (Mpro) of the studied hydrazones. [Display omitted] [ABSTRACT FROM AUTHOR]

• Three heterocyclic hydrazones were synthesized and characterized. • Structural and spectral analyses of the synthesized hydrazones were performed. • DFT method at B3LYP/6–311++ G (d,p) has been used to correlate experimental results. • The synthesized hydrazones have antioxidant and antibacterial activities. • The synthesized hydrazones are potential inhibitors of SARS-CoV-2 main protease. Three hydrazone derivatives have been synthesized using condensation reaction of 4-hydrazinylbenzoic acid with three aromatic aldehydes namely: thiophene-2-carbaldehyde, thiophene-3-carbaldehyde and 2-furaldehyde in ethanol at 78 °C reflux. The synthesized molecules have been characterized using spectroscopic and physicochemical methods including UV–Vis, IR, 1H NMR, 13C NMR, 15N NMR and melting point determination. Optimized molecular structures, UV–Vis and IR spectra modeling, the reactivity, the stability and some quantum chemical parameters of the synthesized molecules were modeled utilizing density functional theory (DFT). The obtained theoretical results were found in good agreement with the experimental results. On the other hand, the antioxidant and antibacterial activities of the molecules under study were evaluated to better understand the associated mechanisms of action specifically. Also, predicted ADME-T and pharmacokinetic parameters indicated that these compounds showed good oral bioavailability. Finally, molecular docking has been used to predict the inhibitory activity of the studied hydrazone derivatives on the SARS-CoV-2 main protease (Mpro). [Display omitted] [ABSTRACT FROM AUTHOR]