Reduction Of Nitro Group Research Articles

Preparation of Highly Dispersed LDHs-based Catalysts and Testing of Nitro Compound Reduction Performance: A Comprehensive Chemical Experiment for Research Transformation

Preparation of Highly Dispersed LDHs-based Catalysts and Testing of Nitro Compound Reduction Performance: A Comprehensive Chemical Experiment for Research Transformation

Chemoselective reduction of aromatic nitro compounds (o-nitrophenol derivatives) using simple borane-THF without transition metal catalysts, additives, or ligands

Chemoselective reduction of aromatic nitro compounds (ortho-nitrophenol derivatives) using Borane in THF (BH3-THF) at room temperature, without using an additional metal catalyst is reported. Interestingly, nitroarenes containing two or three groups, a selective reduction of the nitro group adjacent to the hydroxy group is observed which happens to be the first Chemoselective reduction protocol for nitro groups using BH3-THF. The presence of the phenolic hydroxyl group is found to be the key that aids in hydrogen transfer to the nitro group through a cyclic transition step.

A novel synthesis of β-CD@SA@Ag composite hydrogel microspheres with high catalytic activity and environmental adaptability

The composite of hydrogels and noble metal nanoparticles has wide applications in the field of functional materials. In this paper, we developed a novel and green strategy to synthesize a kind of composite hydrogel microspheres containing silver nanoparticles and β-cyclodextrin (β-CD) modified sodium alginate (β-CD@SA@Ag) without use of strong reducing reagent. First, β-CD was chemical linked to SA by epichlorohydrin (ECH) to form the β-CD modified polymer (β-CD@SA). then AgNO3 was added to the as-prepared polymer solution, in which silver nanoparticles were formed by the reducing power of β-CD units. Subsequently, by reversed-phase emulsion method and ionic cross-linking, a kind of β-CD@SA@Ag hydrogel microspheres were obtained. The structure and morphology of the composite material were characterized in detail by Fourier infrared spectroscopy (FT-IR), thermogravimetric analysis (TG), scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). Test data indicated that silver nanoparticles evenly dispersed in the composite material. On the basis, the adsorption and catalytic performances of the β-CD@SA@Ag hydrogel microspheres were studied towards to the reduction of aromatic nitro compounds. Research results showed that the β-CD@SA@Ag hydrogel microspheres had excellent catalytic activity along with high environmental adaptability. whether in pure water, tap water or river water, aromatic nitro compounds can be completely reduced within 2–13 min. Moreover, the morphology of microspheres of the composite material endows the composite material with high stability and reusability. We believe that our work would provide a new idea for the green synthesis of organic-inorganic composite functional materials.

Borane as reducing reagent of nitroarenes

Aromatic amines are important intermediates in organic synthesis. In this work, an innovative method of synthesizing aromatic amines was designed, which simplified the reduction of nitro groups by using the complexation of borane with neighboring lone pair. The versatility and effectiveness of this technology make it a superior alternative to traditional methods, which is emphasized by the successful application in 12 different examples.

Catalytic reduction of nitro compounds with nano-silver supported by a microporous covalent-organic framework

Covalent-organic frameworks (COFs) with highly ordered porous structures have been widely applied in the field of catalysis and pollution treatment. In this work, a serial of Ag@TAPP-COF composites was successfully synthesized by using 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (TAPP) and thieno [(Cao et al., 2019; Misra and Pandey, 2005) 3,23,2-b]thiophene-2,5-dicarboxaldehyde as monomers. The constructed composites were well characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and N2 adsorption-desorption technique. It is found that Ag@TAPP-COF composites showed high specific surface area and ordered micro pores with plenty of nitrogen and sulfur sites. With these structural advantages, Ag@TAPP-COF composites were developed as excellent and stable catalysts for the reduction of 4-NP. Among them, Ag10@TAPP-COF exhibited the highest catalytic activity with a rate constant of 3.44 s−1 g−1 and an activation energy of 16.2 kJ mol−1. Fascinatingly, Ag10@TAPP-COF can also catalyze the reduction of other kinds of nitro compounds. This work provides an effective method and potential materials for the reduction of nitro compounds.

Selective Reduction of Nitro Compounds by Organosilanes Catalyzed by a Zirconium Metal-Organic Framework Supported Salicylaldimine-Cobalt(II) Complex.

Reducing nitro compounds to amines is a fundamental reaction in producing valuable chemicals in industry. Herein, the synthesis and characterization of a zirconium metal-organic framework-supported salicylaldimine-cobalt(II) chloride (salim-UiO-CoCl) and its application in catalytic reduction of nitro compounds are reported. Salim-UiO-Co displayed excellent catalytic activity in chemoselective reduction of aromatic and aliphatic nitro compounds to the corresponding amines in the presence of phenylsilane as a reducing agent under mild reaction conditions. Salim-UiO-Co catalyzed nitro reduction had a broad substrate scope with excellent tolerance to diverse functional groups, including easily reducible ones such as aldehyde, keto, nitrile, and alkene. Salim-UiO-Co MOF catalyst could be recycled and reused at least 14 times without noticeable losing activity and selectivity. Density functional theory (DFT) studies along with spectroscopic analysis were employed to get into a comprehensive investigation of the reaction mechanism. This work underscores the significance of MOF-supported single-site base-metal catalysts for the sustainable and cost-effective synthesis of chemical feedstocks and fine chemicals.

Synthesis of Oxindoles via SmI2-Promoted Reduction of 2-Nitrophenylacetic Acids

AbstractThe reduction of 2-nitrophenylacetic acids to oxindoles promoted by SmI2 is reported for the first time. This reaction involving the reduction of nitro group proceeds through N–O bond cleavage and direct condensation with the neighboring carboxyl group. From a synthetic point of view, a new method for the synthesis of oxindoles in mild neutral conditions is developed.

Enhancement of Bifunctional Catalytic Performance of G‐C3N4@ Ag Composite by NaBH4 Etching

AbstractHerein, a novel composite of g‐C3N4 and silver nanoparticles(g‐C3N4@Ag) with enhanced bifunctional catalytic activity through chemical etching is reported. A kind of g‐C3N4@Ag composite by one‐pot route, then treated the product with sodium borohydride (NaBH4) solution for a certain time is first synthesized. The property and morphology of the g‐C3N4@Ag composite changed greatly after the treatment. Compared with the pristine g‐C3N4@Ag composite, the NaBH4‐etching endowed g‐C3N4@Ag composite (RACN) with smoother two‐dimensional plane structure, as well as an extension of the conjugate system which originating from the stronger chemical connection between the Ag nanoparticles and g‐C3N4. Furthermore, research results indicated that the RACN showed superior broad‐spectrum catalytic performance for the reduction of aromatic nitro compounds, and the catalytic efficiency of the RACN is enhanced dozens of times by the treatment. Moreover, the photocatalytic activity of the RACN is also greatly improved. This discovery provides an efficient and facile method toward the enhancement of catalytic activity of semiconductor and metal nanoparticle composites by chemical etching.

Employing a magnetic metal organic framework-derived graphene oxide enhanced with incorporated copper: An exceptional catalyst for the selective reduction of organic dyes and nitro compounds

Magnetic metal-organic frameworks have emerged as versatile materials with wide-ranging applications in various scientific fields, particularly catalysis. These materials possess remarkable properties such as magnetic saturation, stability, and biocompatibility, making them highly desirable for numerous applications. In this study, our objective was to design and synthesize a new magnetic metal-organic framework-based catalyst containing copper species. To achieve this, a multi-step approach was employed. Firstly, Fe3O4 nanoparticles were functionalized with silica to prevent aggregation. Subsequently, individual functionalization with glutamic acid and modification with graphene oxide containing copper were carried out. This sequential process resulted in the formation of a unique catalyst, Fe@Si-GA-GO-Cu MOF. To gain insights into the structural and physicochemical properties of the resulting magnetic catalyst, comprehensive characterization techniques were employed. Furthermore, the catalytic behavior and kinetic study of Fe@Si-GA-GO-Cu MOF in the reduction of nitroarenes, methylene blue and Congo red were successfully investigated that demonstrated remarkable efficiency in reducing 4-nitrophenol within a brief timeframe of 9 min. Additionally, it exhibited impressive performance in the reduction of methylene blue and Congo red, achieving reduction times of 57 s and 11 min, respectively. Furthermore, the catalyst highlighted remarkable reusability, retaining its catalytic activity for at least 9 cycles without any pre-activation or significant loss of activity or leaching of copper. The Fe@Si-GA-GO-Cu MOF exhibited several notable advantages such as, smooth and clean reaction conditions at room temperature. This innovative approach not only addresses environmental concerns by preventing pollution from industrial effluents but also significantly accelerates reaction times through the utilization of cost-effective and economical catalysts.

A novel fluorescent probe for ultra-fast detection of CORM-3 and spatiotemporal multi-organelle targeting

Endogenous CO is produced by heme in cells and is involved in various physiological processes. Carbon monoxide releasing molecules (CORMs) could deliver CO-controlled to biological systems. At present, most fluorescent probes used to detect CO or CORM have some problems, such as long response time and toxicity to biological systems. Therefore, this work reports a novel fluorescent probe (PNQ) that can detect CORM-3 real-time based on the coordination of the intramolecular electron-poor double bond and the reduction of nitro group by green and red fluorescence channels. A detail recognition mechanism is proposed. The probe enables ultra-fast detection of CORM-3 without the assistance of other substances and monitors CORM-3 concentrations at the cellular level. Significantly, PNQ is the first case that can detect the concentration of CORM-3 in endoplasmic reticulum and mitochondria based on different fluorescence emission and has the characteristics of spatial and temporal distribution. We believe that this probe has great potential for studying synergistic or antagonistic effects between organelles on CO released by CORM-3 and regulation.

Direct Reductive Coupling of Nitro Compounds for the Synthesis of Advanced Amines

AbstractDirect reductive coupling of nitro compounds with C-coupling partners is an atom- and step-economical strategy to access polyfunctional advanced amines. Due to the extremely complex process involved in the reduction of nitro compounds and the high reactivity of N,O-intermediates, few reliable methodologies have been reported for the reductive coupling of nitro compounds since the initial studies. To address this significant challenge, numerous endeavors have been devoted to this important area over the past hundred years. In this short review, we summarize recent advances in this domain and discuss the mechanisms of these appealing reductive coupling transformations.1 Introduction2 Reductive Coupling of Nitro Compounds with Organometallic Reagents3 Reductive Coupling of Nitro Compounds with Arylboronic Acids4 Reductive Coupling of Nitro Compounds with Alkenes5 Reductive Coupling of Nitro Compounds with Alkyl/Aryl Halides6 Reductive Coupling of Nitro Compounds with Alcohols and Their Derivatives7 Conclusion

A new type of convergent paired electrochemical synthesis of sulfonamides under green and catalyst-free conditions

Our main goal in this work is to synthesize valuable sulfonamide compounds according to the principles of green chemistry and also to present a unique convergent paired mechanism for their synthesis. In this study, we introduced a new type of convergent paired electro-organic synthesis of sulfonamide derivatives via a catalyst, oxidant, halogen and amine-free method. In this research, instead of using toxic amine compounds, an innovative mechanism based on the reduction of nitro compounds and in-situ production of amine compounds was used. The mechanism of electrophile generation is the cathodic reduction of the nitro compound to the hydroxylamine compound and then the anodic oxidation of the hydroxylamine to the nitroso compound. On the other hand, the nucleophile generation mechanism involves the two-electron oxidation of sulfonyl hydrazide to related sulfinic acid at the anode surface. The reaction leading to the synthesis of sulfonamides involves a one-pot reaction of the generated nitroso compound with the produced sulfinic compound.

Biosynthesis of novel Hypercium sabrum extract mediated functionalized Ag@Fe3O4@SiO2 NCs for the efficient removal of poisonous pollutants: Greener journey and bioactivity

The full phytochemical profile and elemental analysis of the Hypercium sabrum plant extract as natural reducing media was investigated. The plant then was employed for green fabrication of recyclable 1-(3-(Trimethoxysilyl)propoxy)-1-hydroxy-2-methylallyl format (TMSPHMAF) and 5-Chloro-1-phenyl tetrazole (CPT) functionalized Ag@Fe3O4@SiO2 nanocomposites (NCs) and their formation mechanism. The structure of green fabricated NCs was elucidated using spectrophotometric, spectroscopic and surface analysis techniques. Also, for better catalytic performance of NCs in reduction of toxic nitro compounds and organic dyes and evaluation of potential removal efficiency (RE) of catalysts, the zero-point charge pH (pHZPC) of their surface was studied. Furthermore, the antimicrobial activities and scolicidal effect of NCs were studied against current pathogenic bacteria and hydatid cysts protoscolices.

Application of pesticide application measures to reduce residue based on the metabolic transfer law of imidacloprid in banana leaves and soil

An investigation of the metabolism and transfer of imidacloprid (IMI) in banana plants and soil was performed using high-resolution mass spectrometry. Results indicated the presence of eight IMI metabolites in soil and leaves that resulted from hydroxylation of the imidazolidine ring, the reduction and loss of nitro groups, and oxidative cleavage of methylene bridges. Six metabolites, including 4/5-hydroxy IMI (4/5-hydroxy), IMI olefin (olefin), and 6-chloronicotinic acid (6-CNA), were detected in the fruits following leaf treatment, while only three were detected after soil treatment. Quantitative analysis showed that the total amount of imidacloprid and its metabolites transferred from leaves to fruits was higher than that transferred from soil to fruits. Therefore, leaf transfer was considered the main means by which IMI and its metabolites transferred to banana fruits. We found that adjuvants tank-mixed with IMI could reduce the total concentration of pesticide transfer from leaves to fruits, especially reducing the amount of metabolites transformed from the reduction and loss of nitro groups and oxidative cleavage of methylene bridges, thus reducing the pesticide residue in fruits and achieving the purpose of reducing the safety risk.

Highly selective reduction of nitro compounds catalyzed by MOF‐derived glucose stabilized Fe3O4 under mild conditions

AbstractBACKGROUNDToday, studies on the catalytic reduction of nitroarenes and dyes are of crucial because nitroarenes, especially 4‐nitrophenol (4‐NPh) and dyes, which are considered important pollutants in wastewater, can pose risks to humans. It is noteworthy that amines are known as valuable intermediates in many industries, therefore, providing an efficient method to achieve these compounds is necessary to protect the environment. In this project, a magnetic MOFs‐based catalyst (containing Cu species as an active site) was found to offer a unique and cost‐effective route for the catalytic reduction of nitroarene and organic dyes.RESULTSIn this study, a novel magnetic catalyst, Fe3O4@glu/Cu‐TAZ‐IMI, based on MOF was synthesized. The core‐shell structure of Fe3O4@glu, functionalized with aspartic acid with TAZ‐IMI and Cu(OAc)2, resulted in the formation of magnetic MOF structure. The structure of this new nanocomposite was identified by X‐ray diffraction (XRD), Fourier Transform Infrared Spectrometer (FTIR), Brunauer–Emmett–Teller (BET), Scanning electron microscopy/energy dispersive X‐ray (SEM/EDX), Thermogravimetric analysis (TGA), High‐resolution transmission electron microscopy (HRTEM), Value stream mapping (VSM), Raman spectroscopy and Inductively coupled plasma‐optical emission spectrometry (ICP‐OES). The catalytic performance of the synthesized catalyst was evaluated for the reduction of nitro compounds and organic dyes, and the results were validated by Gas chromatography‐mass (GC–MS) and ultraviolet light (UV–Vis) spectroscopy. Moreover, the rate constants for the reduction of 4‐NPh, Congo red (CR), and Methylene blue (MB) followed pseudo first‐order kinetics model, which calculated values of 0.31 min−1, 0.355 min−1 and 0.044 s−1, respectively.CONCLUSIONThe catalytic efficacy of Fe3O4@glu/Cu‐TAZ‐IMI catalyst remained intact during the reduction of nitroarenes and organic dyes in aqueous and mild conditions. The findings demonstrate that this novel heterogeneous mesoporous catalyst exhibits exceptional catalytic activity and remarkable stability towards reduction reactions. Moreover, owning to its thermal and structural stability, the catalyst could be easily magnetically separated, recovered, and reused for up to 10 consecutive cycles without experiencing significant activity decline, effectively preventing the depletion of copper species from its structure. © 2023 Society of Chemical Industry.

Highly Functionalized SWCNTs with a Dopamine Derivative as a Support for Pd Nanoparticles: A Recyclable Catalyst for the Reduction of Nitro Compounds and the Heck Reaction.

Single-walled carbon nanotubes (SWCNTs) were functionalized with a dopamine derivative in which the amine group was converted to azide (dopamine azide). The direct reaction of SWCNTs and dopamine azide in o-dichlorobenzene at high temperature (160 °C) led to very highly functionalized CNTs (≈60 wt%). Surprisingly, despite this high degree of functionalization, Raman spectroscopy detected a low disruption of the π-network of the carbonaceous support. This finding was justified by the rehybridization from sp3 to sp2 of the sidewall carbon atoms of CNTs involved in the functionalization process. Further characterization by means of different techniques such as X-ray photoelectron spectroscopy (XPS) analysis and transmission electron microscopy (TEM) allowed to shed some light on the chemical composition and morphology of the obtained material. Moreover, the estimation of the total content of phenolic units and their reducing potential after CNTs functionalization was also assessed using Folin and Ciocalteu and 2,2-diphenyl-1-picryl hydrazide (DPPH) assays. The functionalization of CNTs was exploited to immobilize palladium(II) species that were subsequently reduced with NaBH4 leading to the formation of Pd nanoparticles (NPs). The so obtained hybrid material was used as a recyclable heterogeneous catalyst for the reduction of nitro compounds and the Heck reaction.

Tailored photoenzymatic systems for selective reduction of aliphatic and aromatic nitro compounds fueled by light

The selective enzymatic reduction of nitroaliphatic and nitroaromatic compounds to aliphatic amines and amino-, azoxy- and azo-aromatics, respectively, remains a persisting challenge for biocatalysis. Here we demonstrate the light-powered, selective photoenzymatic synthesis of aliphatic amines and amino-, azoxy- and azo-aromatics from the corresponding nitro compounds. The nitroreductase from Bacillus amyloliquefaciens, in synergy with a photocatalytic system based on chlorophyll, promotes selective conversions of electronically-diverse nitroarenes into a series of aromatic amino, azoxy and azo products with excellent yield (up to 97%). The exploitation of an alternative nitroreductase from Enterobacter cloacae enables the tailoring of a photoenzymatic system for the challenging synthesis of aliphatic amines from nitroalkenes and nitroalkanes (up to 90% yield). This photoenzymatic reduction overcomes the competing bio-Nef reaction, typically hindering the complete enzymatic reduction of nitroaliphatics. The results highlight the usefulness of nitroreductases to create selective photoenzymatic systems for the synthesis of precious chemicals, and the effectiveness of chlorophyll as an innocuous photocatalyst, enabling the use of sunlight to drive the photobiocatalytic reactions.

Recent Developments in Photocatalytic Reduction of Nitro Compounds to Valuable Scaffolds

AbstractThe reduction of nitro compounds is one of the fundamental organic transformations and ascertain wide applicability in industrial chemistry, synthesis of valuable scaffolds, fine chemical synthesis, as well as environmental applicability for decontamination process. The transformation involves the conversion of nitro compounds into valuable scaffolds including amino, nitroso, hydroxyl amines, azo, and hydrazo compounds. Conventional approaches for the reduction of nitro compounds involves the environmentally harmful stoichiometric reagents, high-boiling reaction media, tedious processes, and harsh reaction conditions with high temperature and pressure. Additionally, the selectivity always remains a serious concern associated with the process due to the possibilities of several stable intermediate formation in the reaction pathway of reduction of nitro compounds. Nitro compounds are also of serious environmental concerns being a part of most harmful and high-priority classes of pollutants mainly released from industrial effluents, agricultural waste, and human sewage. A simple degradation of these pollutants bearing nitro group just removes the pollutants, however, the selective reduction of nitro group to valuable functionalities as mentioned above provides the industrially important scaffolds. With the advent of photocatalytic organic transformation, most of the scientific fraternity working in the area of organic synthesis, catalysis, and environmental decontaminations are utilizing the clean, green, low-temperature, energy and cost-effective, sustainable processes for the reduction of nitro compounds to access valuable scaffolds. Nowadays a lot of mechanistic developments in the field ease the processes for the developments of such highly valuable organic transformations. Herein, the present Account is focused on the recent developments in the photocatalytic reduction of nitro compounds to valuable scaffolds.1 Introduction2 Reduction of Nitro Compounds2.1 Conventional Approaches for Reduction of Nitro Compounds2.2 General Photocatalytic Mechanism3 Mechanistic Pathways: Electrochemical, Conventional and Photocatalytic Approaches3.1 Mechanism of Electrochemical Reduction of Nitroarene3.2 Conventional Reduction Mechanism of Nitroarenes3.3 General Photocatalytic Reduction Mechanism of Nitroarenes4 Photocatalytic Reduction of Nitro Compounds to Valuable Scaffolds4.1 Reduction of Nitro Compounds to Corresponding Amines4.2 Reduction of Nitro Compounds to Azo Compounds4.3 Reduction of Nitro Compounds to Azoxy Compounds4.4 Reduction of Nitro Compounds to Nitroso Compounds4.5 Reduction of Nitro Compounds to Hydroxyl Amines5 Future Perspective6 Conclusion

Surfactant-free synthesis of Ag@TiO2 and CuO@TiO2 photocatalyst: a comparative study of their photocatalytic activity for reduction of nitroaromatics in water

The reduction of harmful nitroaromatics to useful amino-aromatics have significant opportunities in synthetic chemistry. Here a visible-light-driven eco-friendly method for the selective reduction of aromatic nitro compounds to their corresponding amines in aqueous solution by using Ag@TiO2 and CuO@TiO2 is described. It was observed that both Ag@TiO2 and CuO@TiO2 are photo-catalytically more efficient compared to bare TiO2 and CuO@TiO2 has higher activity over Ag@TiO2 for the said conversion. The structural and morphological characterization of the as-synthesized catalysts has been done with SEM-EDX, TEM, powder XRD, ICP-AES, XPS, Photoluminescence, and UV-vis spectroscopic techniques. The nanocomposites Ag@TiO2 and CuO@TiO2 exhibit pure anatase phase with average crystallite size of 5.89 nm and 5.87 nm respectively as calculated from the Debye-Scherrer equation depending on the (101) plane. UV-visible results inferred enhanced optical properties of both the synthesized catalysts and revealed a reduced band gap (3.07 eV for Ag@ TiO2 and 2.5 eV for CuO@ TiO2) as compared to neat TiO2 (3.36 eV). Various nitro compounds were tolerated under 150 W LED as a light source (13.9 lumens for an area of 0.2 ft2) in an aqueous medium at room temperature (30 °C) using NaBH4 as a reducing agent to access corresponding amines in satisfying yields (78%–99%). The catalyst can be separated from the reaction mixture by simple centrifugal precipitation and reused for up to six consecutive cycles without apparent loss of its catalytic activity. The products were characterized by 1H-NMR spectroscopic techniques and compared with authentic samples.

Porphyrins – Effective Photocatalysts for Red Light-Induced Functionalizations of Biomolecules

Recently, photoredox catalysis has begun to influence molecular biology and medical sciences for its mild conditions for generating highly reactive species (i.e., radicals), enabling novel and selective functionalisations of biomolecules.[1] In line with this, porphyrins, which can transfer energy (photosensitization) or electrons (photoredox catalysis) when exposure to light, seem to be highly advantageous. Given that their electron absorption shows a characteristic Soret band at 420 nm with a high molar extinction coefficient (105 M-1 cm-1),[2] they have been mainly used in blue-light-induced reactions. These molecules, however, absorb red light (four Q-bands at 518, 553, 592 and 648 nm with molar extinction coefficients of 104 M-1 cm), which has the benefit of low energy, lower health risks,[3] and more in-depth penetration of various media.[4] Fig. 1: Porphyrins in red lightinduced transformationsWe established that due to their diverse photophysical properties, porphyrins promote photoinduced electron transfer events under red light irradiation.[5] They act as effective photooxidants (alkylation of carbonyl compounds, thiol-ne reaction and reductive decarboxylation) and photoreductants (in arylation of heteroarenes, selenylation, thiolation and reduction of nitro compounds). These bioinspired photocatalysts exhibit features that outperform other catalysts operating under red light, as they are really non-toxic and can be applied in biological systems. Thus, we believe that free-radical porphyrins are a valuable contribution to the set of red-light photocatalysts, and this study will lead to more practical biosynthetic applications.