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In this research, for the first time, aminonaphthol derivatives were introduced as efficient corrosion inhibitors. A linear polarization method was employed to investigate the corrosion inhibitory effect of the synthesized aminonaphthols at a concentration of 200 ppm for mild steel acid pickling in 1 M HCl and 0.5 M H2SO4 solutions. The results showed that, even in such strongly corrosive media, all of the synthesized aminonaphthol derivatives exhibit good inhibitory effects toward mild steel corrosion with inhibition efficiencies in the range of 84–95%. A facile, efficient and environmentally friendly method has been introduced for the synthesis of aminonaphthol derivatives by nano-CuO in ionic liquid as a novel catalytic system. Mild, one-pot, operational simplicity and reusability of the catalyst make this protocol highly significant. Experiments showed that these compounds can be used as effective corrosion inhibitors for mild steel acid pickling. The semi-emperical B3LYP method was used for the theoretical calculations. The results of quantum chemical studies confirmed the experimental findings.

A cellulose based magnetic nanocomposite possessing NHC-Cu Complex has been synthesized and characterized. It was then applied as a highly active catalyst in one-pot three-component reaction of sulfonyl azides, secondary amines and triethylamine to afford N -sulfonylformamidines. Copper catalyzed oxidative transformation of C-N bond of triethylamine is a key step to give desired products. In contrast with the good reactivity of the conventional secondary amines, aromatic amines and NH containing heteroaromatics had no activity in these reactions. Moreover, the used nanocatalyst which could be recovered by external magnet, showed reasonable catalytic activity for several times.

Background: Malondialdehyde (MDA) is a commonly used biomarker of oxidative stress in clinical studies and has been measured in many pathological conditions during last decades. Different analytical methods have been reported for determination of MDA in biological samples in which MDA was adducted with thiobarbituric acid (TBA) to produce more sensitive chromophore and also convert it to a fluorescent compound. In spite of the routine applications of this derivatization and subsequent analysis of MDA in biomedical studies, its reliability, repeatability and reproducibility is questionable. The aim of this work is to investigate the effects of some factors on the repeatability of MDA determinations in standard solutions and also in plasma samples using spectroscopic method. Methods: MDA-TBA adduct is prepared in standard solutions and the effects of pH, temperature, reaction time, open, closed and reflux systems and the ratio of MDA and TBA is investigated by measuring the absorbance of the solution at 532 nm. These effects are also investigated in human plasma samples. Results: The best results are obtained at pH 2.5, temperature of 70 °C, reaction time of 150 minutes, reflux system and ratio of 2. Conclusion: Using the optimized conditions are resulted in better repeatability.

A novel tandem Betti/Ullmann/oxidation reaction was used for synthesis of new oxazepine derivatives containing kojic acid. This protocol includes a three-component Betti reaction of 2-naphthol, 2-haloanilines and kojic aldehyde followed by copper-mediated intramolecular Ullmann C-O coupling reaction and subsequently aerobic oxidation. This method provides a new and useful strategy for the construction of heterocycles. Also novel Betti bases based on kojic acid derivatives have been synthesized. In this regard, boric acid functionalized silica supported $$\hbox {Fe}_{3}\hbox {O}_{4}$$ nanoparticle have been designed, synthesized and used as a highly efficient, environmentally benign and recyclable heterogeneous magnetic nanocatalyst for the direct synthesis of desired Betti bases under solvent free conditions. A novel tandem Betti/Ullmann/oxidation reaction was introduced for synthesis of new oxazepine derivatives. This method provides a new and useful strategy for the construction of heterocycles. In this regard, $$\hbox {Fe}_{3}\hbox {O}_{4}$$ @ $$\hbox {SiO}_{2}$$ -boric acid nanoparticles have been synthesized and used for the synthesis of desired novel Betti bases based on kojic acid derivatives.

In this research, nano-SiO2–H3BO3 is introduced as a novel environmentally benign and recyclable heterogeneous catalyst for the synthesis of aminonaphthols under solvent-free conditions without an additional co-catalyst or additive in air. This synthesis method offers several advantages, such as a green and eco-friendly protocol, operational simplicity, mild reaction conditions, short reaction times, higher yields and easy work-up procedures. The work-up of these very clean reactions involves only recrystallization of the product from ethanol and recovery of the catalyst by filtration. The catalyst can be reused several times without losing activity.

This study reports the synthesis and characterization of a highly active catalyst based on chelated copper iodide on magnetic chitosan-salicylaldehyde Schiff base. This catalyst was successfully used for the three-component reaction of N-propargylphthalimide, tosylazide, and NH or OH containing nucleophiles to access new classes of N-sulfonylamidine or N-sulfonylimidate derivatives. The products, which were constructed via an in situ generated sulfonyl keteneimine intermediate, were obtained in good to excellent yields. Short reaction times, easy separation and reusability without significant loss of catalyst activity were found to be the notable features of this synthetic protocol.

Palladium-catalyzed cross-coupling reactions of 2,6-diaryl-3,5-dibromo-4-pyrones with imidazole and benzimidazole in the presence of N,N′-dibutylbenzimidazol-2-ylidene as ligand resulted in the formation of the monosubstituted C- and N-arylated products. Kojic acid was also treated with some aryl halides at the same conditions, to afford C-6 arylated derivatives.

In this study, a highly active catalyst based on copper iodide nanoparticles supported on magnetic aminomethylpyridine functionalized cellulose has been synthesized and characterized. Its catalytic activity was investigated in the multicomponent synthesis of N-sulfonylamidines via an in situ generated sulfonyl ketenimine intermediate under solvent free conditions at room temperature. The desired products were obtained in good to excellent yields at short reaction times. Based on observed results, the synthesized catalyst was an efficient, magnetically separable, recyclable and green catalyst from a natural source.

A novel series of aminokojic acid derivatives were efficiently synthesized by one-pot condensation of kojic acid, aromatic aldehydes and heteroaromatic amines in the presence of cerium(III) sulphate as an efficient and recyclable catalyst in ball-milling under solvent-free conditions at room temperature. This synthesis method offers several advantages, including a green and eco-friendly protocol, operational simplicity, mild reaction conditions, short reaction time, higher yields and easy workup procedures. The workup of these very clean reactions involves only a simple washing with acetone/cold water. The catalytic system can be reused several times with no loss of activity.

Water activity measurements by the isopiestic method have been carried out on the aqueous ternary system of { l -serine + 1-(2-carboxyethyl)-3-methylimidazolium chloride[HOOCEMIM][Cl]} ionic liquid and the aqueous binary system of IL at T = 298.15 K and atmospheric pressure. The data obtained were used to calculate the vapor pressure and osmotic coefficient of solution as a function of concentration. The experimental results for the activity of water were accurately correlated with segment-based local composition models of modified NRTL and UNIQUAC. The fitting quality of the above models has been favorably compared with the NRTL and Wilson models. From these data, the corresponding activity coefficients have been calculated. For the same system, the solubility of the l -serine at various [HOOCEMIM][Cl] ionic liquid concentrations was measured at T = 298.15 K using the gravimetric method. A chemical model was employed to describe the dissociation equilibria of all amino acid species with hydrogen ions in water. Moreover, for l -serine, the chemical model indicated that the formation of cations is insignificant in the [HOOCEMIM][Cl] solution. Also the above local composition models were used to predict the solubility of l -serine in aqueous IL solutions. To provide information regarding (solute + solute) interactions, transfer Gibbs free energies (ΔGtr) of amino acid from water to aqueous IL solutions have been determined.

A novel heterogeneous nanocatalyst was fabricated by depositing copper iodide and Fe3O4 nanoparticles on imidazolium-based ionic liquid-grafted cellulose and successfully characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, powder X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, vibrating sample magnetometry and flame atomic absorption spectrometry. It was employed to catalyse the reaction of terminal acetylenes with sulfonyl azides to afford highly reactive sulfonyl ketenimine intermediates which were subsequently trapped by secondary amines to give N-sulfonylamidines and N-sulfonylacrylamidines under solvent-free conditions at room temperature. Good to excellent yields, very short reaction times, eco-friendly processing, easy separation and reusability without significant loss of catalytic activity were found to be the notable features of this synthetic protocol.

In this study, water activities for the ternary system of { l -serine + 1-carboxymethyl-3-methylimidazolium chloride [Cmmim][Cl] + H2O} and their corresponding binary aqueous solutions have been measured using an improved isopiestic method over the entire homogeneous mixing range at 298.15 K. For the same system, the solubility of the l -serine at various IL concentrations was measured at 298.15 K using gravimetric method. From the vapor–liquid equilibrium measurements, values of the vapor pressure, osmotic coefficient and activity coefficient of solutions were determined. The experimental data for the activity of water, collected in this work, were accurately correlated with segment-based local composition models of the NRTL, modified NRTL, Wilson and NRF-NRTL. The results showed that these models can accurately correlate the water activity data generated in this work. Also the above local composition models used to describe the solubility of amino acid in pure water and in aqueous IL solutions.

Fourteen novel bis-carboxamide derivatives of 4-pyrones were designed and synthesized via Ugi four-component reactions of 4-pyrone carbaldehydes, aromatic amines, isocyanides and carboxylic acids. The cytotoxic activity of synthesized derivatives was evaluated against LS180, MCF-7 and HL-60 cell lines using MTT reduction assay. Synthesized compounds demonstrated strong cytotoxic potential in HL-60 cell line. Compound 12n was the most potent derivative with IC50 values of 16.1, 9.1 and 13.8 μM in LS180, MCF-7 and HL-60 cells, respectively. The results of MLR-QSAR study indicated that topological property of these derivatives directly influenced the cytotoxic potential in HL-60 cell line. Docking study of compounds, conducted for ATP binding site of Src tyrosine kinase, demonstrated the key H-bond interaction with Met 347 of the hinge region.

Novel, one-pot, two-step, sequential protocols for the synthesis of 1,4-phenylene bisheterocyclic compounds have been developed. Successive sequencing of the Groebke–Blackburn–­Bienayme reaction with Ugi-azide, Hantzsch and Biginelli reactions results in rapid and efficient formation of bisheterocyclic compounds. A simple, fast and high yielding method for the synthesis of 3-aminoimidazo[1,2-a]pyridines catalyzed by bismuth(III) chloride under solvent-free conditions is reported. Bismuth(III) chloride is also an efficient catalyst for the Ugi-azide reaction under solvent free conditions.

Palladium-catalyzed cross-coupling reactions of 2,6-diaryl-3,5-dibromo-4-pyrones with imidazole and benzimidazole in the presence of N,N′-dibutylbenzimidazol-2-ylidene as ligand resulted in the formation of the monosubstituted C- and N-arylated products. Kojic acid was also treated with some aryl halides at the same conditions, to afford C-6 arylated derivatives.

A series of mono- and bis-benzimidazolium and imidazolium salts of 4-pyrone derivatives has been synthe- sized in good yields, by various quaternization reactions of halomethyl derivatives of 4H-pyran-4-ones. These salts can be used as novel precursors of functionalized N-heterocyclic carbenes and some of them as novel ionic liquids.

An efficient green chemistry method has been developed for the synthesis of 1-amidoalkyl-2-naphthol derivatives via a one-pot three-component condensation of 2-naphthol, aldehydes and amide in the presence of boric acid as a mild catalyst.

New symmetrical 4-[2-chloro-2-(4-chloro-6-methyl-2-oxo-2H-pyran-3-yl)vinyl]-substituted 1,4-di-hydropyridines were synthesized in moderate to good yields via the modified Hantzsch reaction of β-dicarbonyl compounds with (Z)-3-chloro-3-(4-chloro-6-methyl-2-oxo-2H-pyran-3-yl)acrolein in the presence of an excess amount of NH4OAc. Also, the reaction of β-dicarbonyl compounds with (Z)-3-chloro-3-(4-chloro-6-methyl-2-oxo-2H-pyran-3-yl)acrolein in the presence of enamino esters and ketones was performed, and asymmetrical 4-[2-chloro-2-(4-chloro-6-methyl-2-oxo-2H-pyran-3-yl)vinyl]-substituted 1,4-dihydropyridines were obtained in moderate to good yields at room temperature. The calcium channel blocking activity of these compounds was assessed. They demonstrated moderate to weak effects, although one compound had a comparable effect (IC50 =1.40×10−7 M) with respect to the reference drug Nifedipine.

New 2,6-bis[(3-chlorosulfonyl-4-methyl)phenyl]-4H-pyran-4-one and 2-[(3-chlorosulfonyl-4-methyl)phenyl]-6-methyl-4H-pyran-4-one were synthesized by means of a reaction of chlorosulfonic acid with corresponding pyrones at 0→50°C and were treated with various alcohols and primary and secondary alkyl and aryl amines to give the corresponding sulfonates 4a–e in 20–49% and sulfonamides 3a–l in 55–82% yields. GRAPHICAL ABSTRACT

New 1,4-dihydropyridine derivatives were synthesized by introducing 4-pyrone ring systems at the 4-position of the dihydropyridine nucleus. These compounds were obtained according to Hantzsch reaction. 4-Pyrone carbaldehydes: 4-(4-oxo-6-phenyl-4H-pyran-2-yl)benzaldehyde 4a, 4-(6-methyl-4-oxo-4H-pyran-2-yl)benzaldehyde 4b, 4-oxo-6-phenyl-4H-pyran-2-carbaldehyde 7a, and 6-methyl-4-oxo-4H-pyran-2-carbaldehyde 7b were synthesized and used in these reactions. Then, the calcium channel blocking activity of some of these compounds were evaluated in which they showed weak effects.

A series of fused pyrimidone derivatives of 4-pyrones was synthesized by conversion of the acetates of Baylis−Hillman adducts obtained from 2-formyl-4-pyrones with 2-aminopyridine and 2-aminothiazole.

A novel, rapid method is presented for the synthesis of alkylaminonaphthols using bismuth trichloride as catalyst under neat conditions.

Aldoxime derivatives of 4H-pyran-4-ones 4-7a,b have been synthesized by the reaction of di(aminoxymethyl) pyranones 3a,b with aromatic aldehydes.

A variety of organocatalysts has been screened for the synthesis of arylaminonaphthols. It has been shown that (N,N-dimethylethanolamine) is a highly efficient organocatalyst for the direct synthesis of a novel class of arylaminonaphthols via three-component condensation of 2-naphthol, aldehydes, and arylamines under solvent-free conditions. Mild, one-pot, and green reaction conditions, relatively short reaction times and good yields make this protocol highly significant. 25 new compounds have been synthesized by this method.

New podand and crown ether derivatives of 3,5-disubstituted 4 H -pyran-4-one( 8-11 ) were prepared by the nucleophilic substitution reaction of 3,5-bis(bromomethyl)-2,6-diphenyl-4 H -pyran-4-one with o -nitrophenol, 8-hydroxyquinoline, 2-hydroxymethylpyridine and triethyleneglycol, respectively. The yield of 3,5-bis[(2-formyl-phenoxy)methyl]-2,6-diphenyl-4 H -pyran-4-one has been improved by modification ofour previous method using NaOH instead of Et 3 N. Keywords: Crown ether, Podands, 4 H -pyran-4-one, Open-chain crown, Nucleophilicsubstitution. Introduction Synthetic podands are a family of linear multidentate ligands, which includes acyclic polyethers.They generally form complexes with smaller stability constants than those of correspondingmacrocyclic complexes and thus are usually regarded as poor ligands [2]. In contrast, manyexcellent podands are found in nature. For example, naturally occurring polyether antibiotics, suchas monsin and lasalocid, selectively bind several metal cations and effectively transport them across

The synthesized compounds are tested for their cytotoxic activity against LS180, MCF-7, and HL-60 cell lines.

The procedures allow the access to the biologically important ring system: BiCl3-catalyzed three-component coupling of (het)aromatic aldehydes, 2-aminopyridines, and isocyanides renders possible the synthesis of 3-aminoimidazopyridine derivatives.

A series of novel imidazo[1,2-a]pyridines possessing 4-pyrone ring were synthesized by three-component condensation of 4-pyrone carbaldehydes, 2-aminopyridines and isocyanides. Bismuth (III) chloride was used as a catalyst in these reactions and desired products were synthesized in good yields at a very short period of time under solvent free conditions. UV–Vis absorption and fluorescence emission spectra of these compounds were investigated. It shown that two of these compounds (10f and 10g) exhibit intense fluorescence in dichloromethane. Optimized ground-state molecular geometries and orbital distributions of these two fluorescent dyes were obtained using density functional theory (DFT). Thermogravimetric analysis and electrochemical properties of these compounds were also studied.

A series of mono- and bis-benzimidazolium and imidazolium salts of 4-pyrone derivatives has been synthe- sized in good yields, by various quaternization reactions of halomethyl derivatives of 4H-pyran-4-ones. These salts can be used as novel precursors of functionalized N-heterocyclic carbenes and some of them as novel ionic liquids.

An efficient green chemistry method has been developed for the synthesis of 1-amidoalkyl-2-naphthol derivatives via a one-pot three-component condensation of 2-naphthol, aldehydes and amide in the presence of boric acid as a mild catalyst.

A variety of new symmetrically and unsymmetrically substituted title dihydropyridines (V) and (IV), resp., are synthesized via modified Hantzsch reactions and evaluated for their calcium channel blocking activity.

Title compounds (VII) and (IX) are synthesized starting by Baylis—Hillman reaction of formylpyrones (I) under convenient conditions.

The new β-chloroacrolein with a pyranone moiety (III) is subjected to a three-component Mannich-type reaction with anilines (IV), cyclic ketones (V), and acyclic ketones in the presence of a zirconium catalyst.

2,6-Bis(1H-indole-6-yl)-4H-pyran-4-one was synthesized via Leimgruber–Batcho methodology starting from 2,6-bis(4-methyl-3-nitrophenyl)-4H-pyran-4-one . Enamine intermediate in this reaction, , reacts with aroyl chlorides in the presence of 1,4-diazabicyclo[2.2.2]octane in dioxane to give the substituted enamines . Enamines undergo reductive cyclization with Fe/AcOH to the corresponding 3-aroylindoles 10a ,10b. J. Heterocyclic Chem., 46, 273 (2009).