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High yielding preparation of structurally different anthraquinone lariat ethers from the reaction of a novel anthraquinone aza crown ether 3 with a variety of substituted phenols and paraformaldehyde in the presence of zinc oxide nanoparticles at 100°C in a solvent-free condition has been described. The procedure of these reactions is very simple, the yields are generally high to excellent, and the method is applicable to large scale operation without any problem. Furthermore, the zinc oxide nanoparticles could be recovered and recycled up to five times by simple filtration of the reaction mixture.

Catalytic one-pot condensation of benzil, aldehyde and ammonium acetate have been successfully carried out using 2-hydroxyethylammonium formate (HEAF) grafted on a magnetic nanoparticles as a new heterogeneous catalyst. The as-prepared catalyst was characterized by FT-IR, TEM, FESEM, VSM, TGA and XRD. This catalyst indicated significant advantages, such as excellent yields, shorter reaction time, reusability of the catalyst and easy workup process.

Catalytic Friedel-Crafts acylation of benzene and unactivated benzenes such as chlorobenzene and nitrobenzene have been successfully carried out using activated hematite (α-Fe 2 O 3 ) as a new, heterogeneous and green catalyst. Sonication of neat α-Fe 2 O 3 in a water bath under air atmosphere at room temperature followed by heating at 200 °C, dramatically increase the activity of α-Fe 2 O 3 . With the catalyst loading as low as 5.0 mol%, a wide variety of benzene derivatives were easily converted into the corresponding acylated products in a clean and high-yielding acylation reaction. It was found that the activated α-Fe 2 O 3 could be efficiently recycled and reused several times by simple washing with ethyl acetate, this cannot be attained with most of the traditional catalysts.

A safe, efficient, and improved procedure for the regioselective synthesis of 1-(2-hydroxyethyl)-1H-1,2,3-triazole derivatives under ambient conditions is described. Terminal alkynes reacted with oxiranes and NaN3 in the presence of a copper(I) catalyst, which is prepared by in situ reduction of the copper(II) complex 4 with ascorbic acid, in H2O. The regioselective reactions exclusively gave the corresponding 1,4-disubstituted 1H-1,2,3-triazoles in good to excellent yields. This procedure avoids the handling of organic azides as they are generated in situ, making this already powerful click process even more user-friendly and safe. The remarkable features of this protocol are high yields, very short reaction times, a cleaner reaction profile in an environmentally benign solvent (H2O), its straightforwardness, and the use of nontoxic catalysts. Furthermore, the catalyst could be recovered and recycled by simple filtration of the reaction mixture and reused for ten consecutive trials without significant loss of catalytic activity. No metal-complex leaching was observed after the consecutive catalytic reactions.

An efficient, regioselective, one-pot and two-step synthesis of β-hydroxy 1,4-disubstituted 1,2,3-triazoles from a wide range of non-activated terminal alkynes and epoxides and sodium azide by way of a three-component click reaction using a catalytic amount of [meso-tetrakis(o-chlorophenyl)porphyrinato]copper(II) (5 mol%) in excellent isolated yields is described. The reactions were performed in water as a green solvent at ambient temperature without any additives. By performing two reaction steps in one pot and purifying only at the final step, this procedure excludes any interim purification of in situ generated organic azide intermediates, which significantly improves the overall yield and reduces the reaction time. To benefit from the recovery and reuse of the catalyst, a new heterogeneous catalyst was prepared by simple and successful impregnation of the catalyst onto activated multi-walled carbon nanotubes (AMWCNT). The heterogeneous catalyst was characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic forced microscopy (AFM), and thermogravimetric (TG) analysis to estimate the amount of nitrogen adsorption, and Raman and FT-IR spectroscopy. Leaching experiments after ten successive cycles showed that the catalyst is most strongly anchored to the AMWCNT support. Mechanistically, porphyrinatocopper catalyzes each step of the reaction in different ways as a bifunctional catalyst including epoxide ring opening by azide delivery to epoxide, forming in situ generated 2-azido alcohols followed by activation of the C≡C triple bond of the starting terminal alkynes by forming a porphyrinatocopper-acetylide intermediate and thereby promoting the [3+2]-cycloaddition reaction as the key step to form the triazole framework.

A one-pot procedure for synthesis of 1,2,3-triazole derivatives via the three-component coupling (TCC) reaction between terminal alkynes, benzyl or alkyl halides, and sodium azide in the presences of 1 mol% nanoparticles copper/carbon (Cu/C) catalyst has been developed. The catalyst showed high catalytic activity and 1,4-regioselectivity for the [3+2] Huisgen cycloaddition in water as a “green” solvent and good to excellent yields were obtained in all cases. This procedure eliminates the need to handle organic azides, and they are generated in situ. The reaction has a broad scope and is especially practical for the synthesis of new azacrown ether and anthraquinone derivatives of triazole. The heterogeneous catalysts were fully characterized by scanning electron microscopy (SEM), atomic forced microscopy (AFM), X-ray diffraction (XRD), inductively coupled plasma (ICP) analysis and FT-IR experimental techniques. The catalyst was recycled ten times without significant loss of activity.

The regioselective ring-opening reactions of some epoxides with ammonium thiocyanate in the presence of a series of new 9H-thioxanthen-9-one-fused azacrown ethers, i.e., 7–11 (Scheme 1), and also of dibenzo[18]crown-6 (12), Kryptofix®22 (13), and benzo[15]crown-5 (14) were studied (Tables 1 and 2). The epoxides were subjected to cleavage by NH4SCN in the presence of these catalysts under mild conditions in various aprotic solvents. Reagents and conditions were identified for the synthesis of individual β-hydroxy thiocyanates in high yield and with more than 90% regioselectivity. The results can be discussed in terms of a four-step mechanism (Scheme 2): 1) formation of a complex between catalyst and NH4SCN, 2) release of SCN− from the complex, 3) reaction of the released SCN− at the sterically less hindered site of the epoxide, and 4) regeneration of the catalyst. The major advantages of this method are the high regioselectivity, the simple regeneration of the catalyst, the reuse of it through several cycles without a decrease of activity, and the ease of workup of the reaction mixtures.

Novel PVC membrane (PME) and coated graphite (CGE) Cu2+-selective electrodes based on 5,6,7,8,9,10-hexahydro-2H-1,13,4,7,10-benzodioxatriazacyclopentadecine-3,11(4H,12H)-dione are prepared. The electrodes reveal a Nernstian behavior over wide Cu2+ ion concentration ranges (1.0×10−7–1.0×10−1 M for PME and 1.0×10−8–1.0×10−1 M for CGE) with very low limits of detection (7.8×10−8 M for PME and 9.1×10−9 M for CGE). The potentiometric responses are independent of the pH of the test solutions in the pH range 2.7–6.2. The proposed electrodes possess very good selectivities for Cu2+ over a wide variety of the cations including alkali, alkaline earth, transitions and heavy metal ions. The practical utility of the proposed electrodes have been demonstrated by their use in the study of interactions between copper ions and human growth hormone (hGH) in biological systems, potentiometric titration of copper with EDTA and determination of copper content of a sheep blood serum sample and some other real samples.

The newly synthesized Zn complex is used as a catalyst for the three-component coupling reaction of aldehydes, alkynes, and secondary amines.

Application of Fe3O4 nanoparticles (NPs) as a robust, very efficient, and magnetically recoverable catalyst was investigated in Friedel–Crafts acylation (FCA) of ferrocene and aromatic compounds. This reaction was performed with acid chlorides in solvent-free conditions at room temperature. The catalyst was easily separated by an external magnetic field from the reaction mixture. The separated catalyst was recycled for several consecutive runs without appreciable loss of its catalytic activity. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.

A novel polydentate ligand supported on Fe3O4@SiO2 was designed and demonstrated for the synthesis of Cu nanorods. The Fe3O4@SiO2/EP.EN.EG@Cu was characterized using X-ray diffraction, thermogravimetric analysis, transmission electron microscopy, energy-dispersive X-ray spectroscopy and vibrating sample magnetometry. The Fe3O4@SiO2/EP.EN.EG@Cu showed excellent catalytic efficiency for the cross-coupling reaction of nitrogen-containing heterocycles with aryl halides. The catalyst could be effectively separated from the reaction mixture by simply applying an external magnetic field and reused at least five times without loss of activity.

A novel series of β-lactams bearing an anthraquinone moiety have been synthesized from imines derived from anthraquinone-2-carbaldehyde and ketenes by a [2+2] cycloaddition reaction. The cycloadducts were fully characterized and evaluated for their antimalarial activities against Plasmodium falciparum K14 resistant strain and showed moderate to excellent EC 50 values varying from 9 to 50 μM.

The resin catalyzes the Pechmann condensation of phenols with ethyl or methyl acetoacetate to yield the desired coumarin skeleton under conventional or microwave conditions with similar yields (10 examples).

A safe, efficient, and improved procedure for the regioselective synthesis of 1-(2-hydroxyethyl)-1H-1,2,3-triazole derivatives under ambient conditions is described. Terminal alkynes reacted with oxiranes and NaN3 in the presence of a copper(I) catalyst, which is prepared by in situ reduction of the copper(II) complex 4 with ascorbic acid, in H2O. The regioselective reactions exclusively gave the corresponding 1,4-disubstituted 1H-1,2,3-triazoles in good to excellent yields. This procedure avoids the handling of organic azides as they are generated in situ, making this already powerful click process even more user-friendly and safe. The remarkable features of this protocol are high yields, very short reaction times, a cleaner reaction profile in an environmentally benign solvent (H2O), its straightforwardness, and the use of nontoxic catalysts. Furthermore, the catalyst could be recovered and recycled by simple filtration of the reaction mixture and reused for ten consecutive trials without significant loss of catalytic activity. No metal-complex leaching was observed after the consecutive catalytic reactions.

A one-pot procedure for synthesis of 1,2,3-triazole derivatives via the three-component coupling (TCC) reaction between terminal alkynes, benzyl or alkyl halides, and sodium azide in the presences of 1 mol% nanoparticles copper/carbon (Cu/C) catalyst has been developed. The catalyst showed high catalytic activity and 1,4-regioselectivity for the [3+2] Huisgen cycloaddition in water as a “green” solvent and good to excellent yields were obtained in all cases. This procedure eliminates the need to handle organic azides, and they are generated in situ. The reaction has a broad scope and is especially practical for the synthesis of new azacrown ether and anthraquinone derivatives of triazole. The heterogeneous catalysts were fully characterized by scanning electron microscopy (SEM), atomic forced microscopy (AFM), X-ray diffraction (XRD), inductively coupled plasma (ICP) analysis and FT-IR experimental techniques. The catalyst was recycled ten times without significant loss of activity.

A highly selective synthesis of 2‐substituted benzimidazole derivatives from the reaction of o‐phenylendiamine derivatives and aromatic aldehydes in the presence of an organic salt, NH4OAc, in absolute ethanol is presented. The products were obtained by evaporating the solvent followed by a simple recrystallization with excellent yields.

A simple and efficient solvent-free procedure for the preparation of bis(indolyl)methanes via electrophilic substitution reactions of indoles with aldehydes and ketones is described. The reactions took place in the presence of a catalytic amount of silica chloride at room temperature. The advantages of this method are high yields, short reaction times, low cost, and compliance with green-chemistry protocols.Key words: silica chloride, indole, carbonyl compound, solvent-free, bis(indolyl)methane.