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En el siguiente trabajo se reúnen las conclusiones obtenidas del uso del cloruro de 1,3-bis(carboximetil)imidazolio como catalizador en reacciones de adición de heterociclos a chalconas. Con el uso de este tipo de sistemas, se pretende conseguir un procedimiento sostenible evitando el uso de disolventes en el medio de reacción. De esta forma, se han adicionado diversos heterociclos a una serie de chalconas, obteniendo los correspondientes aductos (de reacción de acoplamiento C-N y C-C) con rendimientos de bajos a excelentes en condiciones de ausencia de disolvente. Aunque los resultados no fueron los esperados, principalmente debido a reacciones secundarias y problemas de volatilidad con los sustratos, resultaron prometedores y se sigue trabajando en refinar este procedimiento para obtener unos mayores rendimientos. Además, se ha realizado un estudio sobre la sostenibilidad de los procesos descritos, siguiendo la metodología de la "EcoScale" y el "E-Factor", obteniendo unos resultados de excelentes a aceptables.

Alien species must adapt to new biogeographical regions to acclimatise and survive. We consider a species to have become invasive if it establishes negative interactions after acclimatisation. Xylella fastidiosa Wells, Raju et al., 1986 (XF) represents Italy’s and Europe’s most recent biological invasion. In Apulia (southern Italy), the XF-encountered Philaenus spumarius L. 1758 (Spittlebugs, Hemiptera: Auchenorrhyncha) can acquire and transmit the bacterium to Olea europaea L., 1753. The management of XF invasion involves various transmission control means, including inundative biological control using Zelus renardii (ZR) Kolenati, 1856 (Hemiptera: Reduviidae). ZR is an alien stenophagous predator of Xylella vectors, recently entered from the Nearctic and acclimated in Europe. Zelus spp. can secrete semiochemicals during interactions with conspecifics and prey, including volatile organic compounds (VOCs) that elicit conspecific defence behavioural responses. Our study describes ZR Brindley’s glands, present in males and females of ZR, which can produce semiochemicals, eliciting conspecific behavioural responses. We scrutinised ZR secretion alone or interacting with P. spumarius. The ZR volatilome includes 2-methyl-propanoic acid, 2-methyl-butanoic acid, and 3-methyl-1-butanol, which are consistent for Z. renardii alone. Olfactometric tests show that these three VOCs, individually tested, generate an avoidance (alarm) response in Z. renardii. 3-Methyl-1-butanol elicited the highest significant repellence, followed by 2-methyl-butanoic and 2-methyl-propanoic acids. The concentrations of the VOCs of ZR decrease during the interaction with P. spumarius. We discuss the potential effects of VOC secretions on the interaction of Z. renardii with P. spumarius.

Designing efficient hydrophilic catalysts for applying in aqueous media is still a great sustainable processes challenge. In this research, glycerol as a non-toxic and biodegradable chemical was used for preparation of water dispersible magnetic nanoparticles which was applied for stabilization of Pd NPs. Resulting composite (Fe3O4@SiO2-T-G@Pd) was characterized using multiple techniques including FTIR, SEM mapping, TEM, XRD, VSM, and TGA. Hydrophilic property of the Fe3O4@SiO2-T-G@Pd was proved by experiments. This magnetic palladium catalyst showed high catalytic performance in the conversion of nitro compounds to corresponding amines as well as in C-C coupling reactions in aqueous media with high efficiency and selectivity. Using this catalyst and NaBH4 as reducing agent, structurally different nitroarenes were reduced to corresponding amines with very good to excellent yields in aqueous media at room temperature. Furthermore, typical Suzuki-Miyaura coupling reaction of 4-bromoanisole with phenylboronic acid was proceeded very well in aqueous media at 60°C. The magnetically water dispersible catalyst was recycled and reused several cycles in the reduction of nitrobenzene without significant loss in its activity and stability such as confirmed TEM, SEM and XPS analyses.

A magnetic nanocomposite comprising imidazolium ionic liquid and glucosamine is successfully synthesized and used for stabilization of Pd nanoparticles. This new material, Fe3O4@SiO2@IL/GA-Pd, is fully characterized and applied as a catalyst in the reduction of nitroaromatic compounds to desired amines at room temperature. Also, the reductive degradation of organic dyes such as methylene blue (MB), methyl orange (MO), and rhodamine B (RhB) is studied and compared with another previous publications. The survey of the stabilization of the palladium catalytic entities is described demonstrating the separation ability and recycling of them. In addition, TEM, XRD, and VSM analyses of the recycled catalyst confirmed its stability.

The synthesis of methyl 3,3-bis[4-(dimethylamino)phenyl]-2,2-dimethylpropanoate is achieved by means of the alkylation of methyl isobutyrate silyl enol ether with bis[4-(dimethylamino)phenyl]methanol, facilitated by using 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) as a solvent and reaction promoter. The reaction proceeds smoothly to produce the mentioned compound in a good yield via a metal and additive-free procedure. The corresponding ester is fully characterized.

In the present study, thirteen elements (Ag, Al, Ba, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Ni, Pb) have been extracted from used cooking oils, olive oils and animal fat. Either inductively coupled plasma optical emission spectrometry (ICP-OES) or tandem mass spectrometry (ICP-MS/MS) have been chosen as detection techniques. Due to the difficulty of directly introducing highly viscous organic samples into the spectrometer, a fast dispersive liquid – liquid aerosol phase extraction (DLLAPE) method has been selected to isolate the analytes from the sample matrix. The DLLAPE is based on the generation of an aerosol from the extracting phase with the help of a pneumatic nebulizer. This high velocity aerosol impacts and penetrates in the liquid sample. Consequently, the liquid – liquid exchange surface area becomes high, thus leading to high extraction yields. A hydrophilic deep eutectic solvent (DES) consisting of choline chloride and ethylene glycol (1:2 mass ratio) has been selected as the extracting solvent. Prior to undertaking the experiments, the extraction method has been evaluated in terms of precision under suitable conditions. In comparison with conventional methods based on sample digestion, sample dilution and shot analysis or extraction assisted by vortex agitation, the DLLAPE shows several advantages, because it is faster, and it provides lower limits of detection than the reference methodologies. The procedural limits of quantification for the determined elements with the DLLAPE in ICP-OES were 0.046 (Ag), 0.396 (Al), 0.013 (Cd), 0.033 (Cr), 0.040 (Cu), 0.20 (Fe), 0.026 (K), 0.026 (Li), 0.33 (Mg), 0.013 (Mn), 2.64 (Ni) and 0.53 (Pb) mg kg−1. Meanwhile, pLOQ in ICP-MS/MS lowered by roughly one order of magnitude. The accuracy of the aerosol phase extraction method has been evaluated through the determination of the recoveries for four representative analytes (Ca, Cu, Mg and Ni) from spiked real samples. For these elements, recovery has taken values of (100 ± 20)%.

La popularidad de los derivados de maleimida ha aumentado constantemente a lo largo de los años, particularmente en los campos de la biotecnología y la química bioorgánica. Esto se puede atribuir a varios factores importantes que destacan sobre las maleimidas, tanto en términos de velocidad, como de reacción, selectividad y rendimiento, así como su buena estabilidad frente al aire, el agua o el calor. Además, varias maleimidas funcionalizadas ahora están disponibles comercialmente o son fácilmente accesibles en unos pocos pasos sintéticos a bajo costo y a través de estrategias escalables y de alto rendimiento. En el presente trabajo se estudiará la posibilidad de sintetizar una maleimida que posteriormente pueda ser útil a la hora de realizar adiciones Michael, consiguiendo de esta manera derivados de aminoácidos que puedan ser de utilidad.

In the present study, for the first time environmentally friendly deep eutectic solvents (DESs) are used as reaction media to perform an efficient, simple and straightforward photocatalytic amide synthesis at room temperature using thioacids and amines. This method features mild conditions, a broad substrate scope, high yields (≤99%) under ambient conditions with air and moisture tolerance. Moreover, the applied operationally mild reaction conditions tolerate the presence of several different functional group substituents on the amine counterpart. Finally, the developed approach allows the recycling of the reaction medium and catalyst for at least three consecutive cycles without a significant decrease in the reaction yield.

En esta memoria se ha llevado a cabo la síntesis de diferentes maleimidas quirales derivadas de aminoácidos, además de sus derivados ésteres metílicos para su posterior evaluación en reacciones de cicloadición 1,3-dipolares multicomponentes. Se estudió del alcance sintético de este proceso con modificaciones en la estructura empleando diferentes aminas, aldehídos y maleimidas con el fin de evaluar la diastereoselectividad demostrando, además, la amplia variabilidad estructural en la síntesis de estos compuestos espirocíclicos, tanto en el dipolo como en el dipolarófilo. Con el objetivo de obtener de forma diastereoselectiva nuevas familias de espiropirrolidinas racémicas, se evaluó el empleo de otros dipolarófilos. También fue posible, a partir de dipolos que contenían maleimidas quirales en su estructura, la síntesis diastereoselectiva en su versión enantiopura obteniendo espiropirrolidinas con relaciones diastereoméricas moderadas.

En los últimos años los alcoholes fluorados, concretamente el 2,2,2-trifluoroetanol (TFE) y el 1,1,1,3,3,3-hexafluoroisopropanol (HFIP), se han utilizado con mayor frecuencia en síntesis orgánica no sólo como disolventes, sino también como mediadores de reacciones orgánicas. Esto es debido a sus propiedades, que los hacen destacar de sus análogos no fluorados como mediadores de transformaciones orgánicas. Por otro lado, en síntesis orgánica, la incorporación de grupos amino es de gran importancia debido a que muchos compuestos bioactivos contienen funciones nitrogenadas. En este sentido, entre las diferentes formas de introducir un grupo amino en una molécula, la utilización de reactivos nitrogenados electrófilos es un método muy atractivo. Así, la reacción de aminación electrofílica de alquenos y sus derivados, mediante O-(2,4-dinitrofenil)hidroxilamina (DPH) como agente de aminación y utilizando HFIP como disolvente y promotor de la reacción, ha abierto un nuevo camino para la obtención de nuevos compuestos nitrogenados evitando el uso de catalizadores metálicos y/o condiciones de reacción más drásticas. De esta forma, en las condiciones óptimas, los correspondientes derivados de oximas se obtuvieron como producto principal de la reacción.

In recent years, the excellent pore volume, huge specific surface area, and easy functionalizable zeolitic imidazolate frameworks (ZIFs), as new type of porous materials, attracted the attention of scientists. In this work, the new Co-based trimetallic Cu-Ni@ZIF-67 was synthesized using embedded the Cu-Ni precursor in ZIF-67. The structure, morphology and properties of Cu-Ni@ZIF-67 was characterized by the various analysis. The catalytic performance of Cu-Ni@ZIF-67 was investigated for tetracycline (TC) degradation and nitroarenes reduction at room temperature. The resultant catalyst was demonstrated excellent TC degradation efficiency by persulfate (PS) activation in the water during 30 min, and Cu-Ni@ZIF-67 was displayed superior catalytic activity for nitroarenes reduction in the presence of NaBH4. Comparing catalytic activity of Cu-Ni@ZIF-67 with Cu/ZIF-67, Ni/ZIF-67, Cu-Ni and ZIF-67 indicated higher activity of Cu-Ni@ZIF-67. Moreover, the recyclability and stability of this catalyst were surveyed.

En la presente memoria se desempeña la síntesis de diferentes MOFs y su uso como catalizadores ácidos en diferentes reacciones orgánicas. Las propiedades de estos materiales (elevada área superficial, alta estabilidad, diversidad estructural, etc.) son motivos de interés para su síntesis y estudio en diferentes ámbitos. Se pretende conseguir una metodología sintética sostenible con el objetivo de evitar el uso de sustancias que son dañinas para el medio ambiente, poniendo en práctica los objetivos de desarrollo sostenible. De esta forma, se llevó a cabo la preparación de distintos materiales metal-orgánicos, basados principalmente en zirconio y cobre con diferentes ligandos derivados de sales del 1,3-bis(carboximetil)imidazol. Estas estructuras de cobre fueron utilizadas como catalizadores en reacciones de apertura de epóxidos, síntesis de cumarinas y síntesis de quinolinas, evaluándose la capacidad catalítica de estos materiales. Los sistemas catalíticos presentados permitieron la reacción entre compuestos carbonílicos y diversos derivados del ácido antranílico.

Benzylic systems such as 9H-xanthenes, 9H-thioxanthenes and 9,10-dihydroacridines can be easily oxidized to the corresponding xanthones, thioxanthones or acridones, respectively, in deep eutectic solvents by a visible blue light-promoted photooxidation procedure carried out using ambient air as oxidant in the presence of riboflavin tetraacetate as a metal-free photocatalyst. The obtained yields are high or almost quantitative, and the reaction media can be recovered and reused. The environmental friendliness of the protocol is demonstrated based on several green metrics.

In this study, bimetallic RuCu supported on l-cysteine functionalized ionic liquid modified magnetic nanoparticles (Fe3O4@IL-Cys-RuCu) was successfully synthesized and characterized. This bimetallic nanocatalyst showed excellent activity in the reduction of 2,3, and 4-nitrophenol isomers and organic dyes as well as catalytic degradation of tetracycline (TC) at room temperature in water. Using this catalyst, complete reduction of nitrophenols was achieved within 9–16 min and degradation of organic dyes and tetracycline were accomplished within 7–4 and 30 min, respectively. The superior activity of bimetallic RuCu compared to similar Ru and Cu catalysts was proved and results indicated that the based on type of reaction, bimetallic catalyst was 2–33 times more efficient than the corresponding monometallic catalysts. This catalyst was recovered and recycled up to 14 times without decreasing in the catalytic activity and stability of the reused catalyst was confirmed by TEM, XRD and XPS.

A novel mixed-linker of iron-based metal–organic frameworks named Fe(INA)(H2N-BDC) has been directly synthesized by mixing 2-amino-1,4-benzenedicarboxylic acid (NH2-BDC) and isonicotinic acid (INA) using hydrothermal method. Its characterization was fully performed by a number of methods such as FT-IR, PXRD, XPS, FESEM, TEM, TGA, ICP and BET and used as a multifunctional bio-photocatalyst for the preparation of 2,4,6-triarylpyridines (TAPs) via tandem photo-oxidation condensation reactions starting from alcohols under sunlight irradiation and air atmosphere in ethanol. Mixed-linker Fe-MOF showed enhanced catalytic activity compared with its analogues with one single ligand, which indicates the synergistic effect of two linkers and Fe-O clusters in Fe(INA)(H2N-BDC) as a photocatalyst with lower band gap. This observation confirmed by an important reduction in the band gap energy and a rise in the characteristic emission of mixed-linker Fe-MOF compared with Fe-MIL-101-NH2 according to the DRS analysis and fluorescence spectrophotometry, respectively. EPR studies clearly indicated that Fe(INA)(H2N-BDC) produces 1O2 and O2•- as active oxygen units under sunlight illumination. Moreover, amine groups in NH2-BDC provide basic functional groups, which in cooperation with acidic sites (Fe in the metal nodes) promote the condensation of the in-situ formed aldehydes with acetophenone and ammonium acetate. Using sunlight irradiation as an energy-saving source, air as a safe oxidant, good yields, reusability of the photocatalyst and any requirement of additives make the present method as an environmentally-friendly method for the preparation of these important scaffolds. This is the first report of the synthesis of TAPs starting from alcohols catalyzed by MOFs.

Chemical recycling offers a convenient solution for the disposal of plastic items made of polyethylene terephthalate (PET), but there is still much room for improvement in terms of integration into the current waste treatment cycles. Recently, deep eutectic solvents (DESs) have exhibited interesting properties in PET glycolysis and hydrolysis, in some cases also in mild conditions. In particular, we recently contributed using Lewis/Brønsted acidic DESs (LBDESs), obtaining good results with iron(III) chloride and sulfonic acids. However, the choice of weaker acids such as acetic acid is more cost-effective and sustainable, with associated reduced risk of corrosion and improved safety. In this study, we demonstrate that a simple post-reaction procedure significantly enhances the yield of terephthalic acid (TA) using FeCl3⋅6H2O/acetic acid (molar ratio 1:1) LBDES, from 4% (literature value) to 54% under the same experimental conditions. Furthermore, we investigate the effect of chloride salts as additives and microwave irradiation on the reaction, reaching quantitative conversion and high yield in TA in 10 minutes and 180 °C.

The N-tert-butanesulfinylimine group behaves as a suitable electron-withdrawing group in 1-azadienes, allowing the diastereoselective synthesis of densely substituted pyrrolidines by 1,3-dipolar cycloadditions (1,3-DCs) with azomethylene ylides. The use of Ag2CO3 as catalyst has allowed one to obtain a wide variety of proline derivatives with high regio- and diastereoselectivities. Subsequent efficient transformations provide valuable proline derivatives, some of which can be used as organocatalysts. The influence of the N-tert-butanesulfinyl group on the diastereoselectivity was studied by computational methods.

Enantioconvergent catalysis has expanded asymmetric synthesis to new methodologies able to convert racemic compounds into a single enantiomer. This review covers recent advances in transition-metal-catalyzed transformations, such as radical-based cross-coupling of racemic alkyl electrophiles with nucleophiles or racemic alkylmetals with electrophiles and reductive cross-coupling of two electrophiles mainly under Ni/bis(oxazoline) catalysis. C–H functionalization of racemic electrophiles or nucleophiles can be performed in an enantioconvergent manner. Hydroalkylation of alkenes, allenes, and acetylenes is an alternative to cross-coupling reactions. Hydrogen autotransfer has been applied to amination of racemic alcohols and C–C bond forming reactions (Guerbet reaction). Other metal-catalyzed reactions involve addition of racemic allylic systems to carbonyl compounds, propargylation of alcohols and phenols, amination of racemic 3-bromooxindoles, allenylation of carbonyl compounds with racemic allenolates or propargyl bromides, and hydroxylation of racemic 1,3-dicarbonyl compounds.

The highly enantioselective organocatalytic synthesis of spirocyclic compounds by Diels-Alder reactions via trienamine using cyclic 2,5-dienones as bisvinylogous precursors and different nitroalkenes as dienophiles is described. The use of cinchonidine-based primary amine as catalyst and benzoic acid as co-catalyst has allowed the construction of a wide variety of spiro compounds containing three stereogenic centres in good yields and excellent diastereo- and enantioselectivities. Additionally, other dienophiles have been evaluated exhibiting different behaviour depending on the electron withdrawing group nature. Subsequent transformations have yielded complex structures with up to five stereocentres. The plausible reaction mechanism has been investigated by computational methods.

Synergistic effects in bimetallic catalysts produce a catalyst with superior activity than a monometallic component. In this work, a novel magnetic crosslinked copoly(ionic liquid) nanohydrogel was synthesized and employed for the stabilization of AuCo bimetallic nanoparticles (Fe3O4@PolyIL-AuCo). This material was characterized using different instrumental techniques such as FT-IR, TGA, XPS, VSM, solid-state UV–Vis, SEM mapping, and TEM. Results indicated a narrow size distribution of nanoparticles and high water dispersibility of Fe3O4@PolyIL-AuCo. Using this catalyst, a series of nitroarenes were reduced to the corresponding amines in aqueous media. In addition, organic dyes were efficiently degraded by this catalyst. Different experiments dealing with the same transformation confirmed that Fe3O4@PolyIL-AuCo exhibited higher catalytic activity than the similar monometallic Au and Co catalysts. This catalyst was recycled for at least 11 consecutive runs with very small deactivation, and TEM, VSM, and XPS confirmed the stability of the reused catalyst.

Low transition temperature mixtures (LTTMs) are a new generation of solvents that have found extensive application in organic synthesis. The interactions between the components often generate highly activated, catalytically active species, thus opening the possibility of using LTTMs as catalysts, rather than solvents. In this work, we introduce a nickel-based imidazolium LTTM, study its thermal behavior and explore its catalytic activity in the solvent-free allylation of heterocycles with allylic alcohols. This system is effective in this reaction, affording the corresponding products in excellent yield without the need for additional purifications, thus resulting in a very environmentally friendly protocol.

We report herein a protocol for the selective activation of C(sp3)–H bonds based on the interplay of two readily available organic catalysts and their successful implementation in cross-coupling azaarenes with alkanes. This Minisci-like reaction is promoted by visible light at room temperature and is free from chemical oxidants, metals, and chlorinated solvents. A wide range of substrates are compatible, including some bioactive molecules. Mechanistic studies support a dual catalytic cycle with H2 evolution.

The synthesis of (E)-2-(1,3-diphenylallyl)-3,5-dimethoxyphenol is described by means of the reaction of 3,5-dimethoxyphenol with (E)-1,3-diphenylprop-2-en-1-ol in 1,1,1,3,3,3-hexafluoroispropanol (HFIP), which acts as a solvent and reaction promoter. The reaction proceeds smoothly to afford the mentioned compound in high yield under a metal and additive-free procedure. The corresponding allylated phenol has been fully characterized.

To overcome numerous health disorders, heterocyclic structures of synthetic or natural origin are utilized, and notably, the emergence of various side effects of existing drugs used for treatment or the resistance of disease-causing microorganisms renders drugs ineffective. Therefore, the discovery of potential therapeutic agents that utilize different modes of action is of utmost significance to circumvent these constraints. Pyrrolidines, pyrrolidine-alkaloids, and pyrrolidine-based hybrid molecules are present in many natural products and pharmacologically important agents. Their key roles in pharmacotherapy make them a versatile scaffold for designing and developing novel biologically active compounds and drug candidates. This review aims to provide an overview of recent advancements (especially during 2015–2023) in the exploration of pyrrolidine derivatives, emphasizing their significance as fundamental components of the skeletal structure. In contrast to previous reviews that have predominantly focused on a singular biological activity associated with these molecules, this review consolidates findings from various investigations encompassing a wide range of important activities (antimicrobial, antiviral, anticancer, anti-inflammatory, anticonvulsant, cholinesterase inhibition, and carbonic anhydrase inhibition) exhibited by pyrrolidine derivatives. This study is also anticipated to serve as a valuable resource for drug research and development endeavors, offering significant insights and guidance.

The 1,3-bis(sulfomethyl)imidazole (bsmim) was effectively prepared by a multicomponent reaction, employing aminomethanesulfonic acid, glyoxal, and formaldehyde. The catalytic activity of bsmim was tested in the synthesis of quinoline derivatives, by means of the Friedländer reaction, and in the allylic substitution of alcohols with nitrogen-containing heterocycles. The performance of sulfo-imidazole derivative (bsmim) resulted in higher comparison with the carboxyimidazole analogs (bcmim and bcmimCl), under the same reaction conditions. This type of ionic organic solid allows the promotion of reactions in the absence of solvent and mild reaction conditions, which improves the sustainability of organic synthetic processes.

A sunlight-induced tandem air oxidation-condensation of alcohols with ortho-substituted anilines or malononitrile for the efficient synthesis of benz-imidazoles/-oxazoles/-thiazoles, or benzylidene malononitrile catalyzed by Co-isatin-Schiff-base-MIL-101(Fe) as a heterogeneous multifunctional bio-photocatalyst is reported. In these reactions, Co-isatin-Schiff-base-MIL-101(Fe) acts both as a photocatalyst, and a Lewis acid to catalyze the reaction of the in-situ formed aldehydes with o-substituted anilines or malononitrile. A significant decrease in the band gap energy and an increase in the characteristic emission of MIL-101(Fe) after functionalization with cobalt Schiff-base according to the DRS analysis and fluorescence spectrophotometry, respectively, indicate that the photocatalytic effectiveness of the catalyst is associated primarily to the synergetic influence of Fe–O cluster and Co-Schiff-base. EPR results obviously pointed out that Co-isatin-Schiff-base-MIL-101(Fe) is capable of creating 1O2 and O2⋅− as active oxygen species under visible light irradiation. Using an inexpensive catalyst, sunlight irradiation, air as a cost-effective and abundant oxidant, and a low amount of the catalyst with recoverability and durability in ethanol as a green solvent, make this methodology as an environmentally friendly process with energy-saving organic synthetic strategies. Furthermore, Co-isatin-Schiff-base-MIL-101(Fe) displays excellent photocatalytic antibacterial activity under sunlight irradiation against E. coli, S. aureus and S. pyogenes. Based on our knowledge, this is the first report of using a bio-photocatalyst for the synthesis of the target molecules.

There is a continuous interest in the development of advanced materials with tunable photophysical properties, among which white light emission represents a major challenge. Indolizines are a kind of azaheterocycles that have gained a great deal of attention in the recent past due to their intriguing photophysical behavior. We report herein on the synthesis of new push–pull indolizines bearing amino and electron-withdrawing groups at positions 1 and 7, respectively, and on their optical response in acidic medium. Exclusive protonation on the amino group has led to a hypsochromic shift in the emission spectra. Interestingly, white photoluminescence can be attained by adjusting the amount of acid as a result of color complementarity between neutral and charged species. Moreover, Density Functional Theory (DFT) calculations on the molecular structure and photophysical properties of these compounds are in agreement with the experimental results, providing very useful information about the main electronic transitions and the influence of protonation on the optical transitions.

Two supported noble metal species, gold and palladium anchored on an ionic liquid-modified Fe-based metal–organic framework (MOF), were successfully synthesized and characterized by FT-IR, XRD, TEM, XPS, SEM, EDX, and elemental mapping. The ionic liquid post-modified MOF was used for anchoring Au or Pd at ppm levels, and the resulting materials were employed as catalysts in the reduction of nitrophenol isomers, dyes, and Sonogashira–Hagihara reactions. Using the Au@Fe-MOF-IL catalyst, reduction of nitrophenol isomers, as well as the reductive degradation of dyes, e.g., methylene blue (MB), methyl orange (MO), and methyl red (MR) were performed efficiently in water. On the other hand, Pd@Fe-MOF-IL was used as an effective catalyst in the Sonogashira–Hagihara coupling reaction of aryl iodides and bromides using very low amounts of Pd. These catalysts were recycled and reused for several runs without deteriorating remarkably in catalytic performance.

The pseudo-multicomponent reaction between propargyl amine, an aldehyde and an electron-deficient alkene is described. The C–H activation takes place thermally and allows the obtaining of cycloadducts in very good yields with high diastereoselectivities. The relative configuration is determined by X-ray diffraction analysis of the chiral molecule, obtained as a single diastereoisomer, using a chiral maleimide. A brief study of the stability of the possible ylides involved in the process is also mentioned, confirming the high diastereoselectivity observed. The high functional group density of these cycloadducts permits the synthesis of complex heterocycles. After allylation or propargylation of the pyrrolidine nitrogen atom, RCM-DA cycloaddition or cyclotrimerization with an alkyne is studied, respectively. In this last example, the resulting tetracyclic structures are of potential interest as drugs for the treatment of cystic fibrosis.

Gold catalysts have been reported to be applied only for the Sonogashira-Hagihara reaction of iodobenzene and phenylacetylene under harsh reaction conditions, while the scope of the reaction has not been expanded for coupling reaction of other aryl halides and alkynes. In this investigation, a cost-effective, Pd-free catalyst based on mesoporous magnesium oxide supported bimetallic AuNi nanoparticles (m-MgO@AuNi) have been synthesized by hydrothermal method and its efficiency has been demonstrated in Sonogashira-Hagihara cross-coupling reaction. The m-MgO@AuNi nanocatalyst was structurally and morphologically characterized using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS) and the mesoporous structure of MgO has been confirmed through BET analysis. Using this palladium-free catalyst, Sonogashira-Hagihara coupling reaction of aryl iodides and aryl bromides with alkynes have been successfully performed and catalyst was recycled for several times. The results demonstrate that the synergistic effect between Au, Ni and mesoporous MgO support plays key role in enhancement of m-MgO@AuNi catalytic activity in Sonogashira-Hagihara reaction.

In this work, we studied the development of a new efficient magnetic catalyst, CuFe2O4/ ZIF-67, for treatment of toxic organic pollutants. The synthesis of catalyst is performed using immobilizing of CuFe2O4 on the surface of ZIF-67 by hydrothermal method. The chemical composition, morphologies and physicochemical properties of CuFe2O4/ ZIF-67 are characterized by different techniques. CuFe2O4/ ZIF-67 is applied for the catalytic degradation of tetracycline (TC), the reduction of 4-nitrophenol (4-NP) and organic dyes such as methylene blue (MB), methyl orange (MO) and methyl red (MR) at room temperature. Using this catalyst, excellent degradation of TC and complete reduction of 4-NP, MB, MO and MR within ≤1 min at room temperature were achieved. The CuFe2O4/ ZIF-67 catalyst showed superior activity compared to the CuFe2O4 and ZIF-67 and surveyed its recyclability at the end of these processes.

Selective semi-oxidation of tetrahydroisoquinoline (THIQ) leads to a valuable dihydroisoquinoline (DHIQ) derivative via singlet oxygen photooxidation process. Typical photosensitisers (i.e., Ru complexes) can activate the reaction even under heterogeneous conditions that facilitate catalyst separation and reusability. In contrast to DHIQ, THIQ acts as an efficient singlet oxygen quencher driving the reaction selectivity. The reaction can also be facilitated by semiconductor catalysts such as MoCo@GW, a glass wool-based catalyst that is easy to separate and reuse and compatible with flow photochemistry. Its role is to mediate the formation of isoquinoline (IQ) and thus an in situ-generated singlet oxygen catalyst. Laser flash photolysis with NIR detection provides proof of the singlet oxygen mechanism proposed and rate constants for the key steps that mediate the oxidation.

Deep eutectic solvents (DESs) have been used for the first time as a sustainable medium in a ruthenium-catalyzed C–H activation reaction. This study describes an efficient, simple and straightfoward protocol for the direct C–H activation of a broad range of aromatic substrates and reaction with several olefins and alkynes, affording interesting heterocyclic systems as products. A simple, robust and commercially available ruthenium catalyst was used along with different DESs under different reaction conditions. This methodology was compatible with the use of either internal or external oxidant (oxygen from air) using a catalytical amount of copper salts for the last case. Different functional directing groups were well tolerated obtaining promising results, that were comparable and even better that those reported in the literature. Also, the reaction medium could be recycled up to 3 consecutive times and this transformation could be carried out on a gram scale with excellent yield. Several green chemistry mass metrics, such as reaction mass efficiency, process mass intensity and optimum efficiency, as well as qualitative parameters were calculated and compared with those of the classical protocols, showing the advantages of using DESs for C–H activation processes.

Bimetallic Fe–Cu MOF was effectively synthesized through a one-pot solvothermal process and successfully characterized by TEM, XPS, SEM, XRD, BET, EDX, elemental mapping, and FT-IR analysis. This bimetallic MOF was employed as a catalyst in the reduction of nitroarenes at room temperature and as well as in the reduction of dyes, for example, methyl orange (MO) and methylene blue (MB). Results pointed to Fe–Cu MOF exhibiting outstanding catalytic performance for both room temperature reactions. The catalytic activity of Fe–Cu MOF in comparison with Fe-MOF and Cu-MOF in the nitroarenes reduction indicated a superior activity compared with single-metal MOFs. Activity of Fe–Cu MOF catalyst did not change after its recycling and reusing for seven consecutive cycles in nitrobenzene reduction.

A new nitrogen-rich hyperbranched polymer comprising imidazolium and triazole moieties used for stabilization of Pd nanoparticles. The resulting new material, PolyTZ-IL@Pd NPs, was characterized with different techniques including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-Ray (EDX), and transmission electron microscopy (TEM) analysis. PolyTZ-IL@Pd NPs has been used as an efficient catalyst in the reduction of nitroarenes to amines and cyanation of aryl bromides and iodides. The catalyst showed high stability and recyclability and recycled at least 10 times in reduction of 1‑chloro-4-nitrobenzene and 5 times in cyanation of iodobenzene.

FeCu MOF has been prepared via solvothermal method and the resulting bimetallic MOF was employed for stabilization of Pd species. Obtained Pd(II)@NH2BDC-FeCu MOF could act as an effective environmental catalyst in Sonogashira-Hagihara coupling reaction and the reduction of organic dyes. This recyclable catalyst demonstrated high catalytic activity for Sonogashira reaction of aryl iodides and aryl bromides with alkynes. Rhodamine B and methyl red as organic dyes were instantly reduced. Pd(II)@NH2BDC-FeCu/MOF was characterized by TEM, XPS, FT-IR, BET, XRD, and SEM. In addition, the synthesized catalyst was recyclable and reusable for 6 sequential times without deteriorating remarkable in catalytic performance for reaction of iodobenzene with phenylacetylene.

A Palladium supported onto an ionic liquid-modified carbon nanotube is prepared. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) are used to complete its characterization. The application as catalyst in the copper-free Sonogashira-Hagihara coupling is also studied employing different substrates. This heterogeneous catalyst is successfully recycled for 5 consecutive identical reactions maintaining its efficiency. After this fifth catalytic run the catalyst is characterized again.

The oxidative dehydrogenation of N-heterocyclic compounds by using H2O2 as oxidant in combination with polar solvents such as 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) and H2O is described. Among these two solvents, the best yields for the heteroaromatic compounds were generally achieved in HFIP. However, it is remarkable, that the use of a non toxic solvent such as H2O gave such good yields. Furthermore, the procedure was implemented in larger-scale and HFIP was distilled from the reaction mixture and reused (up to 5 cycles) without a significant detriment in the reaction outcome.

The Tsuji–Trost reaction of allylic acetates with nucleophiles is optimized using a task-specific ionic liquid (TSIL)-palladium complex in a very efficient manner. Several nucleophiles and allylic systems are studied obtaining very high yields of the corresponding products with total n-selectivity. The reaction is surveyed employing inexpensive allylic alcohols and 3-acyloxindole derivatives affording the expected allylated molecules after a deacylative process. The robustness of the catalytic system is assessed. The recovery and recycling of the whole catalytic system with the ionic liquid is also analyzed and the results are compared with previously reported articles in the literature.

This review covers the recent developments (since 2015) of enantioselective desymmetrization reactions using metal-catalyzed, organocatalyzed and enzymatic processes of prochiral and meso-compounds. This asymmetric strategy has been applied to a great number of organic compounds such as diarylalkanes, silanes, alcohols, amines and dibenzylmethylamines, as well as unsaturated compounds comprising dienes, diynes and cyclohexenes. The classical desymmetrization of 1,2-, 1,3-diols and other polyols by inter- and intramolecular acylation and alkylation reactions, but also by oxidation methods are important processes. Carbonyl compounds such as cycloalkanones, cyclohexadienones, cyclic and acyclic 1,3-diketones, cyclic 1,4-diketones are desymmetrized and applied to the synthesis of a wide range of natural products. In the case of dicarboxylic acid derivatives, diesters and lactones, anhydrides, diamides and dinitriles are mainly desymmetrized by intra- and intermolecular esterifications and hydrolysis. Small ring carbocycles such as cyclopropanes and cyclopropenes, cyclobutanes and cyclobutenes, and also cyclopentanes and cyclopentenes, cyclohexanes and cyclohexenes are considered. Heterocyclic systems such as small ring oxygen containing epoxides, oxetanes and oxabenzonorbornadienes as well as nitrogen containing aziridines, azetidines, azabenzonorbornadienes and diazanorbornenes are desymmetrized mainly by asymmetric ring opening reactions. The synthetic applications of these desymmetrization methodologies in the total synthesis of natural products and biologically active compounds are highlighted.

Performing synthetic transformation using visible light as energy source, in the presence of a photocatalyst as a promoter, is currently of high interest, and oxidation reactions carried out under these conditions using oxygen as the final oxidant are particularly convenient from an environmental point of view. This review summarizes the recent developments achieved in the oxidative dehydrogenation of C–N and C–O bonds, leading to C=N and C=O bonds, respectively, using air or pure oxygen as oxidant and metal-free homogeneous or recyclable heterogeneous photocatalysts under visible light irradiation.

A bimetallic PdCu supported on amine functionalized ZIF-67 is shown to be efficient catalyst in Sonogashira-Hagihara coupling reaction of aryl iodides at room temperature and aryl bromides at 40 ºC. In addition, the catalyst is used in the reduction of 4-nitrophenol (4-NP) at room temperature. The analyses of several experiments are developed in order to demonstrate the existence of synergetic affects between Pd, Cu and Co particles in the named reactions. The stability and reusability of this catalyst are also assessed and its efficiency is compared with other reported catalysts in the same transformations.

En este trabajo se recopilan los resultados del estudio llevado a cabo sobre la elaboración del 1,3-bis(sulfometil)imidazol (bsmim) y su aplicación como catalizador en reacciones donde se obtienen como producto derivados de quinolina y acridina. En primer lugar, se realizaron ensayos para la síntesis de la sal de imidazolio, variando las condiciones de temperatura, tiempo y equivalentes de los reactivos, con el fin de poder aislar la mayor cantidad de bsmim posible. Posteriormente se procedió a utilizar el bsmim para catalizar las reacciones que se mostraran más adelante. Se obtuvieron una serie de derivados de quinolina con buenos rendimientos en general, y de algunos otros productos no se pudo aislar suficiente cantidad.

The development of new techniques for the preparation of organic compounds is important, with catalytic processes being key to this innovation. The development of copper-based metal-organic frameworks to promote oxidative couplings has allowed the synthesis of amides in a very effective manner. This methodology has been successfully applied to the unique preparation of the bioactive compound N,N-diethyl-3-methylbenzamide, with excellent performance (>99% conversion and 95% yield of pure isolated product) on a preparative scale. The described procedure can be classified as an excellent synthesis (EcoScale) considering environmental and economic factors based on different “green metrics” (atom economy, reaction mass efficiency, materials recovery factor, stoichiometric factor, E-factor).

In this work, a new heterogeneous catalyst, comprising gold supported on DABCO-triazole ionic liquid-modified magnetic nanoparticles (Fe3O4@DT-Au), is developed for A3-coupling reaction. This nano-catalyst is characterized using different techniques, such as TEM, SEM, SEM-elemental mapping, XRD, XPS, and TGA. Using a 0.05 mol% of this catalyst, the three-component reaction of amines, aldehydes and alkynes is efficiently performed at 40 °C in water. This catalyst is easily recovered and recycled through external magnetic forces for six times with a small decrease in the activity and re-used catalyst was characterized.

In this work, [Fe3O4@SiO2(CH2)3][DABCO-H][C(CN)3]2 was prepared, identified by various analyses such as FT-IR, EDX, SEM coupled EDX (SEM mapping), XRD, FE-SEM, TEM, TGA, DTG, ICP and VSM and used as a nanomagnetic catalyst for the synthesis of henna-based benzopyrazolo[3,4-b]quinolindiones via cooperative vinylogous anomeric based oxidation under solvent-free condition. Some of these products are new and reported for the first time.

The synthesis of 4-arylthiazol-2(3H)-ones is reported employing a novel and mild methodology using benign solvents. In a second objective the multicomponent preparation of 5,5’-methylenebis[4-arylthiazol-2(3H)-ones] is described following the same strategy. The analysis of the mechanism is also studied and confirmed using chemical tests.

Direct and selective C(sp2)-H/C(sp2)-H cross-dehydrogenative coupling has become a promising strategy to increase molecular complexity with a high atom economy. This study describes an efficient and straightforward protocol for the regioselective C3-H/C3-H cross-coupling of 4-hydroxycoumarin derivatives with quinoxalin-2(1H)-ones, including late-stage modification of natural drugs, promoted by visible light under aerobic conditions at room temperature. With this approach, a wide range of hybrid drug-like molecules were prepared, using air as the terminal oxidant. Remarkably, the C4 OH group at the coumarin ring is essential for the reaction and has been used as a handle for diverse functionalizations of the final products. Moreover, sunlight can promote the reaction under very mild and sustainable conditions, even on a gram scale. Qualitative and semi-quantitative tools were used to demonstrate the greenness advance of this methodology over previously reported ones. Several experiments were conducted to propose a plausible mechanism for this transformation.

(S)-(1-Pyrrolidin-2-ylmethyl)quinuclidine-1-ium bromide was synthesized in a six-step reaction process starting from l-proline and spectroscopically and thermally characterized.