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The present study aimed to synthesize silver nanoparticles (AgNPs) by using black walnut (Juglans negia L.) leaf extract from Iran through a rapidly and ecofriendly ultrasound-assisted method and stirring-assisted method. The synthesized AgNPs by two methods were characterized by different techniques such as Transmission Electron Microscopy (TEM), Scanning Electron Microscope (SEM), and UV–VIS Spectroscopy, FTIR, X-Ray Diffraction (XRD). The antimicrobial activities of both synthesized silver nanoparticles by two methods and also Juglans negia L. leaf extract were determined against four gram negative and two gram positive bacteria by well diffusion method and the Minimum Inhibitory Concentration test (MIC) and the results were comparable. The minimum inhibitory concentrations were achieved for biosynthesized AgNPs with assisted ultrasound method against two gram-negative bacteria E. coli and S. typhimurium (both 8 mg/mL). However, total phenols and flavonoids content of Juglans negia L. leaves extract were also determined. Additionally, the antioxidant activity was evaluated based on 2,2-diphenyl-1-picryl-hydrazyl (DPPH). Total phenols were 78.82±6.83 mg/g gallic acid equivalent, and total flavonoids were 446.23±2.32 mg/g rutin equivalent, and antioxidant capacity was 127.26±0.04 mg/g IC50.

The heme oxygenase (HO) enzyme is a free heme protein that binds to heme in the body. Heme acts as both a cofactor and a substrate in this enzyme. The catabolism of heme into biliverdin, monoxide carbon, and free-iron, catalyzed by heme oxygenase via three consecutive oxygenation steps, in which the heme group functions as the prosthetic group as well as the substrate. Investigations of the reactions of the peripheral substituent on the heme ring with 5-oxaporphyrin iron complexes (verdohemes) have been assumed to provide models and largely unknown for the primary step in the hydrolysis of verdohemes. In this work, a theoretical kinetics and thermodynamics study of the degradation reactions of verdohemes was performed, and calculations show that the [Formula: see text] in the hydrolysis of verdohemes with non-peripheral substituents is more negative than hydrolysis of verdohemes with peripheral substituents. In other words, the hydrolysis of verdohemes with non-peripheral substituents is more energy-efficient than verdohemes with a peripheral substituents. Equilibrium constant calculations show that hydrolysis of verdohemes with non-peripheral substituents is much faster than that of verdohemes with peripheral substituents, which is due to a more convenient nucleophilic attack on the cationic ring than the anionic ring. To acquire a good molecular understanding, peripheral substituent effects on the hydrolysis of verdoheme’s inhibitory role was studied using the DFT method.

The presence of persistent organic pollutants (POPs) in the aquatic environment is causing widespread concern due to their bioaccumulation, toxicity, and possible environmental risk. These contaminants are produced daily in large quantities and released into water bodies. Traditional wastewater treatment plants are ineffective at degrading these pollutants. As a result, the development of long-term and effective POP removal techniques is critical. In water, adsorption removal and photocatalytic degradation of POPs have been identified as energy and cost-efficient solutions. Both technologies have received a lot of attention for their efforts to treat the world's wastewater. Photocatalytic removal of POPs is a promising, effective, and long-lasting method, while adsorption removal of persistent POPs represents a simple, practical method, particularly in decentralized systems and isolated areas. It is critical to develop new adsorbents/photocatalysts with the desired structure, tunable chemistry, and maximum adsorption sites for highly efficient removal of POPs. As a class of recently created multifunctional porous materials, Metal-organic frameworks (MOFs) offer tremendous prospects in adsorptive removal and photocatalytic degradation of POPs for water remediation. This review defines POPs and discusses current research on adsorptive and photocatalytic POP removal using emerging MOFs for each type of POPs.

A green, direct and cost-effective fabrication method is proposed for Eco-environmentally silver nanoparticles (AgNPs) through leaf extraction of Carya illinoinensis from Iran. Formation of Ag NPs was confirmed through different characterization techniques such as UV–Vis Spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM). UV-Visible spectrophotometer showed absorbance peak at 440 nm due to the Surface Plasmon Resonance (SPR). Based on XRD results and SEM and TEM analysis, AgNPs were crystalline with face-centered cubic geometry and in different sizes ranged 12–30 nm. Furthermore, FTIR Spectroscopy was utilized to recognize the specific functional groups responsible for reducing ion silver to silver nanoparticles and the capping agents available in the leaf extract. In addition, the antibacterial effect of Eco-friendly synthesized nanoparticles and also leaf extract, were evaluated on four pathogens by implementing minimum inhibitory concentration test (MIC) and agar diffusion assay. The MIC results exhibits more inhibiting activity against gram-negative microorganisms (Escherichia coli and Pseudomonas aeruginosa) rather than gram-positive microorganisms (Staphylococcus aureus and Listeria monocytogenes). Compared to leaf extract, nanoparticles have better antimicrobial activity against both Gram-positive and Gram-negative bacteria.

In this study, the preparation of silver nanoparticles (Ag NPs) using Tribulus longipetalus Viv. leaf extract was evaluated. Additionally, the in vitro antioxidant and antibacterial activities of the extract were evaluated. The antioxidant activity was assessed by two different approaches based on 2,2-diphenyl-1-picryl-hydrazyl and reducing power assay. The antibacterial activity of the extract, on the other hand, was determined against gram positive and gram negative microorganisms. The AgNPs prepared under the optimal conditions were found to be 15 nm in size and were characterized by ultraviolet–visible spectroscopy, dynamic light scattering, X-ray diffraction and transmission electron microscopy.

The reaction between N-Hydroxy succinimide with dialkyl acetylene dicarboxylates in the presence of isocyanides, leads to functionalized azadienes in good yields. The product were analized and the structures of reaction compounds were deduced from their IR, 1HNMR and 13CNMR spectra.

Microwave-assisted three-component reaction has been established for the synthesis of aryl alkyl ethers. The reaction was carried out under solvent free conditions in the presence of N-methylimidazole and dialkylacetylenedicarboxylate to furnish a novel approach to O-alkylation of phenol derivatives in high yield

The reactive intermediate generated by the addition of tert-butyl and 1,1,3,3-tetramethyl butyl isocyanide to dialkyl acetylenedicarboxylate was trapped by 7-hydroxycoumarin to produce highly functionalized 4H-chromenes in fairly good yields. When the reaction is performed with cyclohexyl isocyanide, 1-azabuta-1,3-dienes were obtained.

Aim and objective Due to biological activity of a significant number of compounds containing benzothiazole ring system and in continuation of our interest in developing new environmentally benign methods for the synthesis of heterocyclic compounds by MCRs in this study we performed an efficient three-component from benzothiazole, acetylenic esters and hydroxyl aromatics compounds to synthesize of 2- benzothiazole derivatives in high yield. Materials and methods IR spectra were recorded using an FTIR apparatus. Melting points measured on an Electrothermal 9100 apparatus. Spectra were obtained in solution of CDCl3 using TMS as internal standard. Elemental analyses were carried out using a Heracus CHN-O- Rapid analyzer. A mixture of benzothiazole, dimethyl acetylenedicarboxylate and phenol were placed in a mortar. The mixture was ground with a mortar and pestle at room temperature for 12 min. After completion of the reaction, as indicated by TLC (ethyl acetate: n-hexane, 1: 3), the solvent was distilled off under reduced pressure and the residue was crystallized from diethyl ether. Results Treatment of benzothiazole and dialkyl acetylenedicarboxylates in presence of resorcinol and β-naphthol led to products 4 (dialkyl (E)-2-(2-(2-hydroxyphenyl)benzo[d]thiazol-3(2H)-yl-3- methylbut-2-enedioate), while we observed two isomer (Z) and (E) configurations (major and minor) in nearly 70:30 ratio when the reaction was repeated in presence of 8-hydroxy quinolone and DMAD. Also when we examined 2-nitro phenol, 4-nitrophenol, and 4-hydroxy quinoline, only one product 5 was obtained. This indicates that the reaction proceeds efficiently with electron-releasing substituted phenols. Conclusion The reaction between benzothiazole and dialkyl acetylenedicarboxylates in the presence of some phenols without electron-withdraw substitution, presents a novel, one-pot, clean, convenient, simple and inexpensive approach into the synthesis of 2-benzothiazole derivatives of potential synthetic and pharmacologically interest. This procedure carries significant advantages because of the minimization of labor, time, and cost.

The 1:1 reactive intermediates generated by the addition of alkyl isocyanides to dialkyl acetylenedicarboxylates were trapped by pyridin-2(1H)-one and isoquinolin-1(2H)-one to yield highly functionalized 1-azabuta-1,3-dienes and, in some cases, minor amounts of ketenimines.

The 1:1 reactive intermediates generated by the addition of alkyl isocyanides to dialkyl acetylenedicarboxylates were trapped by 2-quinolinol to yield highly functionalized ketenimines and, in some cases, minor amounts of 1-azabuta-1,3-dienes.

2,6-Dimethylphenyl isocyanide reacts with benzoyl isothiocyanate in a clean one-pot reaction to afford a sterically congested ten-membered ring containing the S–S–S moiety in nearly quantitative yield. Dynamic effects are observed in the 1H nuclear magnetic resonance (NMR) spectrum of this compound for the restricted rotation around two of the Ar–N single bonds.

The reactive intermediate generated by the addition of alkyl isocyanides to dialkyl acetylenedicarboxylate are trapped by 3-hydroxyisoquinoline to produce highly functionalized 4H-chromenes in 83-92% yields.

An effective route to novel 2,6‐dioxohexahydropyrimidines is described. This involves reaction of alkyl isocyanides and dialkyl acetylenedicarboxylates in the presence of N,N′‐dimethylurea in 1M aq. glucose.

Addition of catechol to methyl propiolate or ethyl phenylpropiolate in the presence of Ph 3 P leads to methyl 2-(1,3-benzodioxol-2-yl)acetate or 3-(1-phenylmethylidene)-1,4-benzodioxin-2-one. 2-Aminophenols react with alkyl propiolates in the presence of Ph 3 P to produce a nearly 1:1 mixture of 3-methyl-2H-1,4-benzoxazin-2-one derivatives and methyl (E)-3-(2-aminophenoxy)-2-propenoates.

The crystal structure of tert-butyl coumarin-3-carboxylate has been determined. This compound crystallizes in the triclinic space group P-1 with cell parameters a = 5.8038(9) A, b = 9.3022(16) A, c = 12.421(2) A, β = 97.107(5)°, V = 610.71(17) A3, D calc = 1.339 mg m−3, and Z = 2. The final R value is 0.0593 for 2396 reflections. The adjacent molecules form a cyclic dimer by intermolecular hydrogen bonds of type C=O...H with their carbonyl group and the hydrogen on C(3).

Ethyl 2-arylamino-2-oxo-acetates undergo a complex reaction with dimethyl acetylendicarboxylate in the presence of triphenylphosphine to produce dimethyl 1-aryl-4-ethoxy-5-oxo-2,5-dihydro-1H-pyrrole-2,3-dicarboxylates in good yields. Dynamic NMR study of dimethyl 1-(2-methyl-6-nitrophenyl)-4-ethoxy-5-oxo-2,5-dihydro-1H-pyrrole-2,3-dicarboxylate shows a fairly high energy barrier (ΔG # = 95 ± 2 kJ mol− 1) for rotation around the N-aryl single bond, which leads to an observable atropisomerism.

The structures and relative energies for the basic conformations of cyclohexyne (1), cycloheptyne (2), and cyclooctyne (3) have been calculated by the HF/6-31G*, MP2/6-31G*, and B3LYP/6-31G* methods. The C2 symmetric twist conformer of 1 is calculated to be more stable than the planar C2v geometry. Ring inversion of the envelope conformation of 2 takes place via C2 symmetric twist transition state, which is 34.0 kJ mol−1 higher than the envelope form. The C2 symmetric chair conformation of 3 is calculated to be 11.7 kJ mol−1 more stable than the unsymmetrical twist-boat (3-TB) geometry. Interconversion of the chair conformation and 3-TB takes place via an unsymmetrical transition state, which is 37.6 kJ mol−1 less stable than the chair form. Conformational racemization of the chiral 3-TB takes place via the boat transition state. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006

The 1:1 reactive intermediate generated by the addition of alkyl isocyanides to dialkyl acetylenedicarboxylates was trapped by fairly strong NH-acids such as carbazole, indole, or pyrrole to yield highly functionalized 1-azadienes and ketenimines.

An effective route to novel coumarines and 4H-chromenes is described. This involves the reaction of tert-butyl isocyanide and dialkyl acetylenedicarboxylates in the presence of 2-hydroxybenzaldehydes.

The reactive intermediate generated by the addition of alkyl isocyanides to dialkyl acetylenedicarboxylate was trapped by 6-quinolinol to produce highlyfunctionalized 4 H -chromenes in fairly good yields.

(7S, 14S, 16R)- dialkyl 6-oxo-6,7,13,14-tetrahydro-7,14-methanobenzo[d]chromeno[3,4- h][1,6,3]oxathiazo-nine-14,16-dicarboxylates 4 and (S)-methyl 2-(2-methoxy-2-oxoethyl)-2,3- dihydrobenzo[d]thiazole-2-carboxylates 5 were readily synthesized in a ratio 3:1 and moderated yield by multicomponent reactions of 4-hydroxycoumarin and acetylenic esters with benzothiazole without using a catalyst. Also, The GIAO/DFT approach at the B3LYP/6-31G** level of theory was used to calculate the (1)H, (15)N, (17)O and (13)C NMR chemical shifts of product 4b. These computations are performed on the basis of X-ray structural data which are collected at 120(2) K temperature. In order to take into account intermolecular hydrogen bonds and the van der Waals effects, two different sizes of clusters (two model of trimeric and pentameric clusters) have been considered. A comparison between the experimental (Exp.) and calculated (Cal.) (1)H and (13)C NMR chemical shifts may reveal that the solution contains monomer, trimer1, trimer2, and pentamer models.

Alkyl-(aryl) isocyanides react with benzoyl isothiocyanate in the presence of dialkyl acetylenedicarboxylates or dibenzoylacetylene in one-pot to afford highly substituted 4,7-bis[alkyl(aryl)imino]-2-phenyl-3-oxa-6-thia-1-azaspiro[4.4]nona-1,8-dienes, with double insertion of the isocyanide, in 38–45% yields (based on the isocyanide).

Reaction of tert -butyl isocyanide with electron-deficient acetylenic esters in the presence of N 1 -[( Z )-1-benzoyl-3-oxo-3-phenyl-1-propenyl]-2-(2-furyl)-2-oxoacetamide leads to dialkyl 5- tert -butylamino-[2,2′]bifuranyl-3,4-dicarboxylates in moderate yields.

The addition of isocyanides to esters (III) generates a reactive intermediate which is trapped by 6-quinolinol.

A simple one-pot synthesis of functionalized 4-hydroxyquinoline derivatives is presented which as the advantage of neutral conditions.

The three-component one-pot reaction of pyridin-2(1H)-one or isoquinolin-1(2H)-one (I), isocyanides (II), and activated acetylenes (III) yields 1-azabuta-1,3-dienes of type (IV).

2,6-Dimethylphenyl isocyanide reacts with benzoyl isothiocyanate in a clean one-pot reaction to afford a sterically congested ten-membered ring containing the S–S–S moiety in nearly quantitative yield. Dynamic effects are observed in the 1H nuclear magnetic resonance (NMR) spectrum of this compound for the restricted rotation around two of the Ar–N single bonds.

An effective route to novel 2,6‐dioxohexahydropyrimidines is described. This involves reaction of alkyl isocyanides and dialkyl acetylenedicarboxylates in the presence of N,N′‐dimethylurea in 1M aq. glucose.

Benzoyl isothiocyanate reacts with dialkyl acetylenedicarboxylates in the presence of triphenylphosphine in a mechanistically novel reaction to afford highly substituted dialkyl 2-(benzoylimino)-5-phenyl-4H-[1,3]dithiolo[4,5-b]pyrrole-4,6-dicarboxylates with double insertion of the isothiocyanate. The reaction proceeds via a carbon to nitrogen migration of an alkoxycarbonyl group.

Alkyl isocyanides react with 2-hydroxybenzaldehyde or 2-hydroxy-5-nitrobenzaldehyde to afford N -alkyl-2-aryl-2-oxoacetamides and N 2 , N 4 -dialkyl-2-aryl-4 H -1,3-benzodioxine-2,4-dicarboxamides in nearly 1:1 ratios. Treatment of 2,6-dimethylphenyl isocyanide with 2-hydroxy-5-nitrobenzaldehyde affords only the 2-oxoacetamide derivative.

The regioselective reaction of N1-benzyl-N2-(4-nitrophenyl)ethanediamide with dialkyl acetylenedicarboxylates or alkyl propiolates in the presence of triphenylphosphine leads to dialkyl 4-benzylamino-1-(4-nitrophenyl)-5-oxo-2,5-dihydro-1H-pyrrole-2,3-dicarboxylates or alkyl 4-benzylamino-1-(4-nitrophenyl)-2-oxo-5-pyrrolidinecarboxylates in good yields.

The 1:1 adduct produced in the reaction between tert-butyl isocyanide and dialkyl acetylenedicarboxylates was trapped by alkyl 2-fluoro-anilino-2-oxo-acetates or ethyl 2-oxo-2-(trifluoromethylanilino)-acetate to produce functionalised ketenimines in good yields. Dynamic NMR effects were observed in the 1H NMR spectra of these compounds as a result of restricted rotation around the single bond linking the aryl group to the ketenimine system. The free energy of activation (ΔG≠) for this process is 64.9–66.5 kJ mol−1.

Alkyl cinnamates are formed in fairly good yields from the reaction of dialkyl acetylenedicarboxylates and 3-hydroxy-4-methoxybenzaldehyde in the presence of triphenylphosphine.

Addition of 1-naphthol, 2-naphthol or 3-hydroxybenzaldehyde to tert-butyl propiolate in the presence of triphenylphosphine leads to tert-butyl 2-arylacrylates and tert-butyl 3-aryloxypropenoates in nearly 1:1 ratio. When phenol, 3-hydroxy-4-methoxybenzaldehyde, 8-hydroxyquinoline or 7-hydroxycoumarin was employed as OH-acid, only alkyl 3-aryloxypropenoates were obtained.

The regioselective reactions of N 1 -alkyl- N 2 -(4-nitrophenyl)ethanediamide with dialkyl acetylenedicarboxylates in the presence of tert -butyl isocyanide lead to dialkyl 2-{[2-(alkylamino)-2-oxoacetyl]-4-nitroanilino}-3-[( tert -butylimino)methylene]succinates in good yields.

The reaction of dibenzoylacetylene and enaminocarbonyl compounds leads to 3-alkylidene-2,3-dihydro-1H-pyrrol-2-ol derivatives in nearly quantitative yields. The reaction of this heterocyclic system with alcohols in the presence of a catalytic amount of HCl produces highly functionalized pyrroles in good yields.

The reactions of dibenzoylacetylene with cyclic enaminocarbonyls in the THF–H 2 O system lead to 3-alkylidene-1,2,3,5,6,7-hexahydro-4 H -indol-4-one derivatives in high yields.

Alkyl 2-(2-fluoro-anilino)-2-oxo-acetates or ethyl 2-oxo-2-(trifluoromethylanilino)-acetate undergo a multistep reaction with dialkyl acetylenedicarboxylates in the presence of triphenylphosphine to produce dialkyl 1-(2-fluorophenyl)-4-alkoxy-5-oxo-2,5-dihydro1H-pyrrole-2,3-dicarboxylates or dialkyl 4-ethoxy-5-oxo-1-[2-(trifluoromethyl)-phenyl]-2,5-dihydro-1H-pyrrole-2,3-dicarboxylates in good yields. Dynamic NMR study of dimethyl 4-ethoxy-5-oxo-1-[2-(trifluoromethyl)-phenyl]-2,5-dihydro-1H-pyrrole-2,3-dicarboxylate shows a fairly high energy barrier (ΔG ≠ = 60.9 kJ mol - 1 ) for rotation around the N-aryl single bond, which leads to an observable atropisomerism.

The 1:1 reactive intermediates produced in the reaction between alkyl isocyanides and dialkyl acetylenedicarboxylates were trapped with N-aryl-2,2,2-trichloroacetamides. When the aryl group was 1-naphthyl, two products were obtained in nearly 2:1 ratio.

Alkyl isocyanides react with dialkyl acetylendicarboxylates in the presence of CH-acids such as cyclopentane-1,3-dione, cyclohexane-1,3-dione, or 5,5-dimethylcyclohexane-1,3-dione to afford highly functionalized 4H-pyrans in fairly high yields. In the case of reaction between dimethyl acetylenedicarboxylate and 5,5-dimethylcyclohexane-1,3-dione in the presence of cyclohexyl isocyanide or benzyl isocyanide tetrahydro-cyclopenta[b]pyran derivatives were isolated in addition to the 4H-pyran system. The free energy barrier (96.9 kJ mol−1) for restricted rotation around the polarized double bond of the enaminone moiety in dimethyl 2-[cyclohexylamino-(4,4-dimethyl-2,6-dioxocyclohexylidene)methyl]but-2-enedioate was determined by dynamic NMR spectroscopy.