In this study, a new series of 2,7-dichloro-4-(2-substituted-amino acetyl)fluorene derivatives were synthesized, characterized and evaluated for their antimicrobial activity and screened for cytotoxic activity against human lung carcinoma (A-549) and human breast carcinoma (MCF-7) cell lines. Most of the synthesized compounds displayed significant activity against A-549 and MCF-7 cell lines when compared to 5-fluorouracil (5-FU), which was used as a reference drug. In addition, some of these reported novel compounds exhibited promising antibacterial and antifungal properties. A molecular docking study was performed to identify the mechanism of action of the synthesized compounds, which suggested binding interactions with the active sites of dihydrofolate reductase (DHFR).

Background

Sulfonamide derivatives are of great attention due to their wide spectrum of biological activities. Sulfonamides conjugated with acetamide fragments exhibit antimicrobial and anticancer activities. The inhibition dihydrofolate reductase (DHFR) is considered as one of the most prominent mechanism though which sulfonamide derivatives exhibits antimicrobial and antitumor activities.

Results

In this study, a new series of 2-(arylamino)acetamides and N-arylacetamides containing sulfonamide moieties were designed, synthesized, characterized and assessed for their antimicrobial activity and screened for cytotoxic activity against human lung carcinoma (A-549) and human breast carcinoma (MCF-7) cell lines. A molecular docking study was performed to identify the mode of action of the synthesized compounds and their good binding interactions were observed with the active sites of dihydrofolate reductase (DHFR).

Conclusion

Most of the synthesized compounds showed significant activity against A-549 and MCF-7 when compared to 5-Fluorouracil (5-FU), which was used as a reference drug. Some of these synthesized compounds are active as antibacterial and antifungal agents.

A simplistic and highly effective protocol for the synthesis of a new class of poly-functionalized innovative nicotinonitriles incorporating pyrene and/or fluorene moieties has been developed through the domino four-component condensation reaction of 1-(pyren-1-yl)ethanone/1-(9H-fluoren-2-yl)ethanone, numerous aromatic aldehydes, and 3-oxo-3-(pyren-1-yl)propanenitrile/3-(9H-fluoren-2-yl)-3-oxopropanenitrile and ammonium acetate in acetic acid as a reaction medium. The advantages of this approach are the short reaction time, excellent yield, and the easy experimental workup that affords substrate diversity and operative competence under metal-free reaction conditions for the formation of C–C and C–N bonds. The substituent effects on the photophysical property-based absorption and the emission of the synthesized compounds in dichloromethane have been well-investigated. Strong absorption quenching of around 100 nm was observed when substitution of the benzene ring at the C₄-position of the pyridine moiety occurred with an electron-donating (–N(CH₃)₂) group. All of the newly synthesized nicotinonitrile derivatives showed strong blue-green fluorescence emission with maxima in the range between 420–630 nm. These highly pronounced emission spectra will help this family of compounds to find application in many areas and the field of materials science.

Steel and its alloys are essential materials in various industries, but they quickly react with the surrounding environment, especially humid ones, which leads to their destruction and corrosion on a large scale. Replacing synthetic organic inhibitors with plant-extracted or natural molecules has recently been a major challenge in terms of environmental and industrial aspects. In this report, the inhibitory dominance, adsorption of myrrh extract (MRE) as a green corrosion inhibitor on 330 stainless steel (SS) in 1.0 M HCl solution at the temperature range of 25 to 55 °C were explored. Weight loss (WL) measurements showed apparent inhibition efficiency (% IE) of MRE of up to 93.6% at 55 °C. The % IE values increased sharply with increasing inhibitor concentration and medium temperature. Adsorption investigations confirmed that the extract molecules were strongly adsorbed on the SS surface and were consistent with the Langmuir and Frumkin models. Polarization monitoring showed that the MRE behaves as a mixed-type inhibitor. EIS was also used to quantitatively evaluate the efficiency of the passive layer on the SS surface. All thermodynamic (DH, DS, DG) and kinetic (Kads, Ea) parameters were calculated and analyzed. XPS was used to inspect the surface chemistry of SS and the nature of MRE-SS bonds. AFM demonstrated that the SS sample in the blank solution appears to be severely damaged and has the highest roughness of about 382.6 nm, compared to that obtained in the presence of MRE (145.61 nm). Various theoretical and computational methods were used to predict the performance of the examined inhibitor. All experimental findings of the different techniques are in excellent agreement with each other and with theoretical speculations. The outcomes of this study are thought to have some bearing on the sensible development of a potent inhibitor against the corrosion of metals in acidic environments.

Although drugs are essential for humans, they are perilous for the ecosystem when disposed of improperly. There are challenges in reusing them for other useful purposes, most notably as corrosion inhibitors; corrosion inhibition is an important industrial and economic aspect of protecting metals and the environment. Copper alloys are widely used in outdoor applications, especially in casting decorative items, but they have shortcomings in corrosion resistance. Herein, the ability of two expired drugs, streptomycin (I) and neomycin (II), to resist the corrosion of a high Cu–Zn alloy in a 3.5% NaCl environment was studied in detail via electrochemical, gravimetric and microscopic techniques as well as theoretical calculations. The electrochemical results showed that there was an increase in the corrosion rate of the examined alloy with increasing [NaCl]. The addition of 500 mg L−1 of the tested drugs strongly inhibited alloy corrosion, and the inhibition efficiencies (% IEs) reached 87.4% and 91.6% with drugs I and II, respectively. The obtained gravimetric outcomes indicated that the values of % IEs were augmented with increasing drug dosages, while they decreased as [NaCl] and solution temperature increased. The higher % IEs were attributed to the strong adsorption of the drugs on the brass surface. This adsorption was suggested to be physical and obeyed the Langmuir adsorption isotherm. Polarization assessments indicated that these drugs were mixed-type inhibitors with an anodic priority. All thermodynamic/kinetic parameters were determined through full adsorption assays, and the possible inhibition mechanism was proposed. Computational methods provided further support and clarification of the inhibition mechanism of these drugs. All results of the applied techniques were in excellent conformity with each other and with the employed computational methods.

 Steel corrosion is a serious problem not only economically but also has a negative impact on our safety. In this report, the inhibitory efficiency of the synthetic chlorinated cyclic imide named f (CCIBA) on the corrosion of carbon steel (CS) in 1.0 M sulfuric acid solution was explored using different experimental and theoretical methods. Weight loss and electrochemical measurements were used to determine the inhibition efficacy (%IE) of CCIBA. The findings revealed that with the increase of CCIBA concentration, the corrosion rate omitted and the %IE value increased to 93%. While with the increase of temperature, the CS corrodes strongly. The higher values of %IE were proposed to be due to strong adsorption of the CCIBA molecules on the CS surface and such adsorption was mainly chemicalinits natureand wasconsistentwiththe Langmuiradsorption isotherms.Polarizationcurves revealed thatCCIBAbehaved as a mixed-type inhibitor. It was also shown that icorr values decreased sharply from 5930 to 417μA cm−2 with the addition of 29 × 10−6 M CCIBA. Impedance measurements demonstrated that raising the CCIBA concentration increased charge transfer. The coefficient values of kinetics and thermodynamics were calculated. Based on the data obtained, the inhibition mechanism was proposed. Computational predictions are in good agreement with experimental measurements.

Herein, Two new acridin-pyrazole Schiff bases, (E)-2-phenyl-5-propyl-N-(1,2,3,4-tetrahydroacridin-9-yl)-2,4- dihydro-3H-pyrazol-3-imine (APS-1) and (E)-5-(methoxymethyl)-2-phenyl-N-(1,2,3,4-tetrahydroacridin-9-yl)- 2,4-dihydro-3H-pyrazol-3-imine (APS-2), were synthesized and their anticorrosion activities for carbon steel (CS) were evaluated in 1 M HCl solution. Atomic Force Microscopy (AFM), mass loss (ML), potentiodynamic polarization (PDP) and electrochemical impedance measurement (EIS) were used to investigate their surface, and inhibition performance (η %). ML measurements of APS-1 and APS-2 (5 mM) showed η% values of 93.3% and 95.0% at 298 K, respectively. Adsorption studies confirmed that they have physical-chemical interactions and obeyed the Langmuir model. PDP measurements showed that they had a mixed nature. EIS experiments revealed that they increased the resistance of CS to charge transfer while simultaneously reducing the double layer capacitance. Theoretical calculations using density functional theory (DFT) and molecular dynamics (MD) simulation were also performed to investigate the adsorption patterns of the synthesized compounds on the Fe (110) surface. The mechanism of inhibition is proposed and elucidated. The experimental measurements were in complete agreement with the theoretical predictions.

Because of its unique properties, zinc is widely used in many industries, including medical devices, electronics, and automotive components, but it is susceptible to corrosion, especially in salty environments. In this context, the inhibitory efficacy of two environmentally friendly expired drugs, gatifloxacin (Gat) and levofloxacin (Lev), on zinc corrosion in 3.5 % NaCl solution was investigated using several techniques at different temperatures. Kinetic and thermodynamic evaluations confirmed that the adsorption strength of these compounds on the metal surface plays an effective role in their inhibitory capacity, and this certainly depends on their chemical structure. The inhibition efficiencies (% IEs) were calculated to be 87 % and 89 % for Gat and Lev using 500 mg/L of drug and at 298 K, respectively. Potentiodynamic polarization (PDP) studies have classified these drugs as anodic-type inhibitors. Adsorption assessments have shown that it is a physical process following the Langmuir isotherm. Electrochemical impedance spectroscopy (EIS) experiments have demonstrated good adhesion and stability of the protective film on the metal surface resulting from the adsorption of these compounds. Inhibition mechanisms have also been provided. Response surface methodology (RSM) analysis was used to analyze the data and predict the response. The experimental results of all the techniques used and the statistical and computational analysis were in remarkable agreement with each other.