Aldehydes In Water Research Articles

Multifunctional Heterogeneous Cobalt Catalyst for the One-Pot Synthesis of Benzimidazoles by Reductive Coupling of Dinitroarenes with Aldehydes in Water.

The endeavor of sustainable chemistry has led to significant advancements in green methodologies aimed at minimizing environmental impact while maximizing efficiency. Herein, a straightforward synthesis of benzimidazoles by reductive coupling of o-dinitroarenes with aldehydes is first ever reported in aqueous media using a non-noble metal catalyst. This work demonstrates that the combination of nitrogen and phosphorous ligands in the synthesis of supported heteroatom-incorporated Co nanoparticles is crucial for obtaining the desired benzimidazoles. The process achieves > 99% conversion, > 99% chemoselectivity and stability for the reduction of dinitroarenes using water as the solvent and hydrogen as the reductant under mild reaction conditions. The robustness of the catalyst has been investigated using several advanced techniques such as HRTEM, HAADF-STEM, XEDS, EELS, and NAP-XPS. In fact, we have shown that the introduction of N and P dopants prevents metal leaching and the sintering of the cobalt nanoparticles. Finally, to explore the general catalytic performance, a wide range of substituted dinitroarenes and benzaldehydes were evaluated, yielding benzimidazoles with competitive and scalable results, including MBIB (94% yield), which exhibits favorable biological properties and cytotoxic activity against several types of cancer.

Homobimetallic Ruthenium(II) Complexes Catalysed Selective Transfer Hydrogenation of Aldehydes in Water.

Herein we report chemoselective transfer hydrogenation (TH) of aldehydes in aqueous medium using a series of homobimetallic Ru(II) catalysts. Two homobimetallic complexes (Ru1 and Ru3) and one monometallic complex (Ru2) have been employed in the catalytic reduction of aldehydes. Bimetallic complex [(p-cymene)2(RuCl)2L3] (Ru3) is obtained from the reaction of Schiff base ligand 2,2'-((1E,1'E)-((3,3',5,5'-tetraisopropyl-[1,1'-biphenyl]-4,4'diyl)bis(azaneylylidene))bis(methaneylylidene))bis(4-bromophenol) (H2L3) and characterized by various spectroscopic and analytical techniques. The use of formic acid/formate buffer as the hydride source and a catalyst loading of 0.01 mol% of Ru1 or Ru3 resulted in the conversion of various aldehydes to the corresponding alcohols in good to excellent yield. This method is very efficient for selective reduction of aldehydes in the presence of other reducible functional groups. A loading of 0.0001 mol% of Ru1 catalyst is sufficient to achieve a turnover frequency (TOF) of 5.5× 105 h-1. Furthermore, the catalyst can been recycled and reused for six consecutives cycles without sacrificing the efficiency. A comparison of results obtained between bimetallic and monometallic complexes offers valuable insights into the distinct reactivity patterns of the bimetallic complexes, presumably originating from a cooperative effect. We have explored the mechanistic pathway using DFT methods.

Visible Light-Mediated Co(II) Catalyzed Synthesis of α,β-Epoxy Ketones by Oxidative Coupling of Alkenes and Aldehydes in Water.

A one-step, two-component visible light-mediated CoCl2·6H2O-catalyzed oxidative acylation of alkenes by aldehydes to synthesize α,β-epoxy ketone has been achieved in water at room temperature. The photocatalytic activity of Co(II) presented a remarkable achievement for synthesis of α,β-epoxy ketones from aldehydes and olefins, with a wide substrate compatibility including aromatic, heteroaromatic and aliphatic aldehydes, styrenes with both electron-donating and withdrawing groups, α-substituted styrenes, stilbene, acrylates, and even the challenging unactivated aliphatic alkenes. Mechanistic studies including radical trapping experiments, intermediate detection by GCMS, Hammett analysis, and DFT studies unveil the nature of the photocatalytic pathway.

Alginate-modified surfactants functionalized metal-organic framework-based fluorescent film sensors for detection and adsorption of volatile aldehydes in water

Volatile aldehydes have an adverse impact on both human health and the environment, therefore, a fast, straightforward, highly accurate detection technique for the simultaneous detection and removal of several aldehydes is eagerly anticipated. Herein, novel APGF@ZIF-8 and APOF@ZIF-8 sensing materials were developed by coating fluorescent alginate-modified surfactants (APGF and APOF) into the ZIF-8 MOFs to produce quite porous fluorescent sensors (SBET up to 1519 m2/g). The detection capacity of the prepared sensors for benzaldehyde, glyoxal, formaldehyde, and acetaldehyde has been examined. The detection mechanism was suggested as hydrogen bonding formation between the sensors and volatile aldehydes as confirmed by Gaussian calculations. All the fluorescence spectra of aldehydes display remarkable linear detection relationships in the range of 0.05–200 μM with the limits of detection (LOD) values in the range of 0.001–0.18 μM (0.106–10.44 ppb). These sensors were utilized successfully to detect multiple volatile aldehydes in river water samples with satisfactory recoveries of 96–107 %. Interestingly, fluorescent APGF@ZIF-8/CS and APOF@ZIF-8/CS films as portable disposable removal techniques for benzaldehyde, glyoxal, formaldehyde, and acetaldehyde from water were fabricated. APOF@ZIF-8/CS exhibited an excellent formaldehyde adsorption capacity of 58.30 mg/g and an adsorption removal efficiency of 93.5 %. The adsorption process of biosorbent on various aldehydes was fitted by Freundlich adsorption isotherm. The adsorption kinetics followed Pseudo-second-order kinetic model.

Catalytic hydrogenation of lignin-derived aldehydes over bimetallic PdNi/hydrotalcite catalyst under mild conditions

Selective conversion of lignin derivatives into value-added chemicals benefits to develop sustainable chemical engineering and material manufacturing. In this work, a hydrotalcite-supported PdNi bimetallic catalyst was synthesized by introducing Ni to promote Pd dispersion and adjust the charge distribution of the active center, which was used for the catalytic hydrogenation of lignin-derived aldehydes in water under mild conditions. At 30 ℃ and 2 MPa H2, PdNi/HT achieved 99 % of vanillin (VAN) conversion with 100 % selectivity of vanillyl alcohol (VAL), and most of the typical lignin-derived aldehydes could be hydrogenated over this catalyst. This catalyst was steady and could be recycled at least five runs. The introduction of Ni and the nanosheet structure of HT improved the dispersion of the metal particles, significantly reducing the metal particle size. Besides, the Pdδ−–Niδ+ pair and the basic sites of HT facilitated the H2 activation and the adsorption of the aldehyde groups of lignin-derived aldehydes on the catalyst surface, enhancing the hydrogenation efficiency and selectivity.

Electrochemical Synthesis of 5‐Benzylidenebarbiturate Derivatives and Their Application as Colorimetric Cyanide Probe

AbstractA highly efficient, fast, catalyst‐free, and atom economical method was developed for the synthesis of 5‐benzylidenebarbiturates. Thus, reacting barbituric acid and aldehydes in water as a green solvent under electrochemical conditions afforded the synthesis of the target compounds in six minutes and in highly pure forms. The effects of solvent, reaction time, temperature, electrolyte, and electrode material were studied to optimize the reaction conditions. The scope of the reaction was broadened by the synthesis of 5‐(arylidene)barbiturate derivatives 3 a–3 q using different aldehydes. Calculation of the green chemistry metrics proved the efficiency of the reaction in terms of E‐factor, mass intensity, mass productivity, and reaction mass efficiency. Compound 3 g [5‐(4‐(dimethylamino)benzylidene) barbiturate] was used for the colorimetric detection of cyanide ion over dynamic linear range 1–25 μM with limit of detection (LOD) of 0.86 μM.

A facile and practical p-toluenesulfonic acid catalyzed route to dicoumarols and their biological evaluation

ABSTRACT New Dicoumarols 2a-g efficiently synthesized employing p-TSA as a catalyst from the reaction of 4-hydroxycoumarin with aryl aldehydes in water. This method offers direct access to structurally diverse Dicoumarols derivatives in a good yields (65-94%). Upon heating 3,3' -arylidenebis-4-hydroxycoumarins derivative in acetic anhydride, the epoxydicoumarins were formed. 1H, 13C{1H}-NMR, elemental analysis, and infrared spectroscopic techniques were used for the characterization of the obtained compounds. A possible relationship between such hydrogen-bonded structures and the antimicrobial and the antioxidant activities of compounds is suggested. The synthetized compounds 2a-g and 3a-g were subjected to in vitro antimicrobial and antifungal activities against DNA gyrase and Mycobacterium tuberculosis-CYP51 target proteins at the active sites. Compound 3d shows effective inhibitory effect in terms of MIC = 15 µg mL-1. against Salmonella typhimuriumATCC 14028. Compounds 2b, 2c, 3b, 3c, 3e and 3g have recorded an important scavenging activity against the radical DPPH. The EC50 of these compounds was 47.17, 46.90, 50.55,48.27 , 46.55 and 47.54 µg mL-1 respectively. Investigation of the anti-inflammatory activity of the synthesized compounds showed that compounds 2b,2c, 3f, 3b and 3c are the most potent inflammatory activities.

Diastereoselective Preparation of Spiro[2,3‐dihydrofuran‐3,3’‐oxindole] Derivatives by an Atom‐Economic Tandem Reaction in Water

AbstractA catalyst‐free tandem reaction was developed for the clean synthesis of spiro[2,3‐dihydrofuran‐3,3’‐oxindole] derivatives from 2‐(2‐oxoindolin‐3‐yl)malononitriles and aldehydes in water. This method has an extensive substrate scope. The targeted products were easily isolated by filtration in high yields and excellent diastereoselectivities. The reaction also features numerous advantages, including step/atom economy, both catalyst and additive‐free, no organic solvents, simple work‐up, short reaction times, and environmentally friendly conditions. The present strategy utilizes simple conditions, demonstrating the potential application in the synthesis of pharmaceuticals and biologically active compounds.

VUV/UV oxidation performance for the elimination of recalcitrant aldehydes in water and its variation along the light-path

Vacuum ultraviolet/ultraviolet (VUV/UV) oxidation using a low-pressure mercury lamp emitting dual wavelengths (185 nm (VUV) and 254 nm (UV)) significantly varies in performance along the light-path (lP), which has not been fully characterized. Therefore, VUV/UV oxidation in solution was investigated at various lP in terms of the degradation kinetics and mineralization pathway of representative aldehydes with various alkyl-chain lengths. Oxidative degradation of parent aldehydes with shorter alkyl chains was less efficient, specifically the pseudo-zero-order rate constant (kobs) of formaldehyde was only 51% of that of propionaldehyde (kobs = 0.078 μM s−1). In contrast, the mineralization of aldehydes with longer alkyl chains was less efficient because these aldehydes underwent mineralization into more refractory carboxylic byproducts, e.g., oxalic acid. VUV was mainly absorbed by superficial water (lP < 0.55 cm), which resulted in highly heterogeneous oxidation in homogeneous water. Thus, kobs of acetaldehyde dramatically decreased from 0.13 to 0.033 μM s−1 as the total lP of solution increased from 1.0 to 3.0 cm. On the basis of mineralization pathways proposed above, an iterative kinetic model was developed to characterize the degradation of parent aldehydes and the formation of carboxylic acids along lP. This model predicted the VUV/UV oxidaton for the first time by considering the fast diffusion of pollutants by limited diffusion of transient radical species. Thus, it realized the prediction of •OH concentration at specific water solution and byproduct evolution within specific water solution in turbulent flow regime, wherein •OH was predominantly formed in superficial water-layers wherein •OH in water-layers of lP <0.16 cm and <0.81 cm contributed to 50% and 90% of the total oxidation performance, respectively. This result would help to improve the VUV-UV-reactor design in terms of optimizing the thickness of water-layer and turbulence of water-flow.

Acceptorless Dehydrogenation of Alcohols and Transfer Hydrogenation of Aldehydes in Water Using a Single Bifunctional, Bistate, Water-soluble Ruthenium Catalyst.

A water-soluble bifunctional, bistate ruthenium catalyst has been developed using the 8-aminoquinoline ligand which responds to an acid-base stimuli and is catalytically active for two complementary reactions. The "Ru-amino state" is highly active for catalytic transfer hydrogenation of various aldehydes using formic acid as the hydrogen source resulting in a range of primary alcohols. On the other hand, the "Ru-amido state" is active for the acceptorless dehydrogenation of alcohols to yield carboxylate salts or ketones. The reactions can be carried out in air without an inert atmosphere and the products can be purified by simple extraction without the use of any chromatographic techniques. A range of functional groups which include electron-rich and deficient (hetero)arenes and alkenes, alkynes, halides, esters, cyano, and nitro groups, are all well tolerated, indicating excellent chemoselectivity for transfer hydrogenation.

Preferential Synthesis and Pharmacological Evaluation of Mono‐ and Di‐substituted Benzimidazole Derivatives

AbstractA series of substituted benzimidazoles were synthesized by condensing o‐phenylenediamine with aromatic aldehydes in water using surfactants as catalyst. Mono and disubstituted benzimidazoles were formed preferentially with benzalkonium chloride and sodium dodecyl sulfate respectively. In silico molecular docking study revealed that 1‐(4‐chlorobenzyl)‐2‐(4‐chlorophenyl)‐1H‐benzo[d]imidazole bound strongly with delta, mu and kappa opioid receptors with binding scores of −9.4, −8.7 and −9.9 Kcal/mol respectively. This derivative also possessed highest binding (−9.0 Kcal/mol) against tubulin (binding score of albendazole was −6.4 Kcal/mol). The molecule also showed potential antibacterial activity with MIC50ranging 16–128 μg/ml inin vitroantibacterial assay. Two benzimidazole derivatives showed powerful interaction with cyclooxygenase‐1 and cyclooxygenase‐2 (−8.1 and −8.9 Kcal/mol respectively) indicating their high analgesic and anti‐inflammatory potentials. All the compounds produced significant binding (−5.2 to −8.2 Kcal/mol) towards urate oxidase, glutathione reductase and peroxiredoxin. Monosubstituted derivative 4‐(1H‐benzo[d]imidazol‐2‐yl)phenol displayed superior binding (−6.5 Kcal/mol) with glucosamine 6‐phosphate synthase compared to ciprofloxacin (−6.3 Kcal/mol). In PASS analysis, monosubstituted derivatives demonstrated significant drug‐like potential (Pa&gt;0.7). Hence, the synthesized benzimidazole derivatives can be used as potential leads for developing new drugs.

First Asymmetric Synthesis of Passerini‐Type Condensation Products in Water Using Pregabalin: A Chiral Amino Acid for the Efficient Asymmetric Induction

AbstractThis article describes the use of Pregabalin as a commercially available chiral amino acid in the efficient synthesis of the Passerini‐type condensation products via two‐component condensation of aromatic aldehydes with cyclohexyl isocyanide. All reactions are accompanied with aerobic oxidation of aldehydes in water leading to chiral α‐acyloxycarboxamides with moderate to good enantioselectivities (up to 88 % ee) under green conditions such as nonmetal source. This is the first report of asymmetric synthesis of Passerini products in water.

Precise control of selective hydrogenation of α,β-unsaturated aldehydes in water mediated by ammonia borane

Hydrogenation of unsaturated biomass in a control manner is highly desirable but challenging, especially under mild conditions. We here report selective hydrogenation of α,β-unsaturated aldehydes (UALs), featuring a precise control of all potential products by adjustment of the role of ammonia borane (AB) in transfer and/or catalytic hydrogenation. The hydrogenation can be readily operated in neat water without using any external H2-source, because AB as the H2-source is favorable in aqueous solution. Impressively, unsaturated alcohols are prepared in 100% conversion by the room-temperature transfer hydrogenation of UALs with AB, while saturated aldehydes are obtained in 100% conversion and > 90% selectivity with high activity (i.e., turnover frequency = 0.98 s−1 for cinnamaldehyde), by the catalytic hydrogenation with H2 released from AB and Pd immobilized on two-dimensional metal organic layer. On the other hand, UALs can be completely converted into the saturated alcohols through a combination of transfer and catalytic hydrogenation in one pot. This strategy can be extended to more than 8 types of UALs, and provides a facile way to fine-control the selective hydrogenation of unsaturated compounds with competing bonds.

Synthesis and Application of β‐Alkynyl‐γ,γ‐Difluoroallylboronates for Metal‐Free Allylation of Aldehydes in Water

Abstractβ‐Alkynyl substituted γ,γ‐difluoroallyl‐boronates were prepared via defluorination under basic condition. Allylation reaction of aldehydes with gem‐difluoroallylboronates under metal‐free condition in water was developed. As the sole solvent, water dramatically improved the efficiency of the reaction, and afforded the desired products in 48–92% yields. The corresponding difluorinated alcohols were smoothly transformed into the 3,3‐difluoro‐4‐methylene‐3,4‐dihydro‐2H‐pyran derivatives in the presence of gold catalyst.magnified image

Cooperative N-Heterocyclic Carbene/Nickel-Catalyzed Hydroacylation of 1,3-Dienes with Aldehydes in Water

Cooperative N-Heterocyclic Carbene/Nickel-Catalyzed Hydroacylation of 1,3-Dienes with Aldehydes in Water

Narcissistic self-sorting and enhanced luminescence via catenation in water

Narcissistic self-sorting, namely that components are able to distinguish ‘self’ from ‘non-self’ during self-assembly, was accomplished via catenation by condensing multiple hydrazides and an aldehyde, or a hydrazide and multiple aldehydes in water. The underneath mechanism of this behavior relies on the corresponding homo [2]catenanes which are thermodynamically more favored than their hetero counterparts because the former containing two identical macrocyclic components are able to maximize the inter-component non-covalent forces. One of these catenanes contains four 4-phenylpyridinium units, which are often considered barely luminescent because of intramolecular rotations and vibrations that lead to non-radiative annihilation of their excited states. These intramolecular motions, however, are restricted upon integrating 4-phenylpyridiniums within the catenane architecture. As a consequence, compared to its non-interlocked counterparts, this catenane exhibits enhanced fluorescence, which represents a novel conceptual model for developing luminescent materials.

Encapsulated Ni-Co alloy nanoparticles as efficient catalyst for hydrodeoxygenation of biomass derivatives in water

Catalytic hydrodeoxygenation (HDO) is one of the most promising strategies to transform oxygen-rich biomass derivatives into high value-added chemicals and fuels, but highly challenging due to the lack of highly efficient nonprecious metal catalysts. Herein, we report for the first time of a facile synthetic approach to controllably fabricate well-defined Ni-Co alloy NPs confined on the tip of N-CNTs as HDO catalyst. The resultant Ni-Co alloy catalyst possesses outstanding HDO performance towards biomass-derived vanillin into 2-methoxy-4-methylphenol in water with 100% conversion efficiency and selectivity under mild reaction conditions, surpassing the reported high performance nonprecious HDO catalysts. Impressively, our experimental results also unveil that the Ni-Co alloy catalyst can be generically applied to catalyze HDO of vanillin derivatives and other aromatic aldehydes in water with 100% conversion efficiency and over 90% selectivity. Importantly, our DFT calculations and experimental results confirm that the achieved outstanding HDO catalytic performance is due to the greatly promoted selective adsorption and activation of C=O, and desorption of the activated hydrogen species by the synergism of the alloyed Ni-Co NPs. The findings of this work affords a new strategy to design and develop efficient transition metal-based catalysts for HDO reactions in water.

Water extract of pomegranate ash as waste-originated biorenewable catalyst for the novel synthesis of chiral tert‑butanesulfinyl aldimines in water

• Biorenewable waste-derived base as catalyst in water. • Highly sustainable synthesis of chiral tert ‑butanesulfinyl aldimines. • Non-chromatographic purification of products. • Fair reusability of the renewable catalyst and multi-gram scale viability. The renewable materials catalyzed reactions in aqueous media is urgently needed and highly fascinating task in the current state of organic synthesis. Here, we report a novel and sustainable protocol for the biorenewable, waste-originated water extract of pomegranate ash (WEPA) catalyzed condensation reaction of tert ‑butanesulfinamides and aldehydes in water to produce chiral tert ‑butanesulfinyl aldimines ( t BSAIs) in high yields. The products are separated by filtration and purified by recrystallization; avoids the extraction and column chromatographic separation steps. The reaction was performed with high yields in several consecutive recycles of the catalyst and medium, and further this method is highly effective for the multi-gram scale synthesis of t BSAIs. The application of biorenewable catalyst, added metal/catalyst free conditions, absence of volatile organic solvents and additives, vast substrate feasibility, economical profiles, easy operation, reusability of the catalyst, large scale viability, non-chromatographic purification of products and tremendous future perspective are the sparkling insights of this development. A novel and versatile protocol has been developed for the synthesis of tert‑butanesulfinyl aldimines using water extract of pomegranate ash (WEPA) as catalyst in water.

Green Approach for Preparation of New Hybrids of 5‐Substituted‐1H‐Tetrazoles Using Novel Recyclable Nanocatalyst based on Copper(II) Anchored onto Glucosamine Grafted to Fe3O4@SiO2

AbstractThe novel copper(II) ions decorated Fe3O4@SiO2 composite magnetic spheres were synthesized by grafting copper(II) ions onto glucosamine modified Fe3O4@SiO2 NPs. The magnetic Fe3O4@SiO2−TCT−GA−Cu(II) catalyst were characterized by varies physicochemical techniques such as FT‐IR, FE‐SEM, TEM, DLS, XRD, EDX, VSM, TGA, VSM, ICP, and UV‐Vis. The catalytic performance of this novel catalyst was studied in the green preparation of 5‐substituted 1H‐tetrazole based hybrids via three‐component and one‐pot reaction of sodium azide, hydroxylamine hydrochloride, and various aldehydes in water and ethylene glycol, as a green solvent mixture. This green protocol provides significant advantages such as non‐vigorous conditions, short reaction times, outstanding yield of desired tetrazoles, minimizing of chemical waste, wide‐ranging substrate, quick and efficient work‐up procedure and using environmentally benign, durable, cost effective, magnetically separable, reusable nanocatalyst.

Electrochemically induced synthesis of quinazolinones via cathode hydration of o-aminobenzonitriles in aqueous solutions.

An efficient and practical electrochemically catalyzed transition metal-free process for the synthesis of substituted quinazolinones from simple and readily available o-aminobenzonitriles and aldehydes in water has been accomplished. I2/base and water play an unprecedented and vital role in the reaction. By electrochemically catalysed hydrolysis of o-aminobenzonitriles, the synthesis of quinazolinones with benzaldehyde was first proposed. The synthetic utility of this method was demonstrated by gram-scale operation, as well as the preparation of bioactive N-(2,5-dichlorophenyl)-6-(2,2,2-trifluoroethoxy) pteridin-4-amine, which enables straightforward, practical and environmentally benign quinazolinone formation.