Reduction Of Nitro Group Research Articles

Three‐dimensional porous magnetic polyaniline supported Ag nanoparticles nanocomposites as an efficient and recyclable catalyst for nitrophenol reduction

AbstractAg nanoparticles (Ag NPs) nanocomposites are promising catalysts for nitro compound reduction, but simultaneously meeting the requirements of high catalytic activity, stability, recyclability and facile preparation is highly difficult. Herein, the three‐dimensional (3D) porous magnetic polyaniline (PANI) was synthesized using phytic acid (PA) as the dopant/crosslinker, and a recyclable PANI/Ag NPs nanocomposite (PMPA) was obtained through the in situ redox between PANI and AgNO3. Characterization results demonstrate that PMPA exhibits a typical 3D porous structure constructed by coral‐like PANI framework with well‐dispersed Ag NPs (10–20 nm) firmly anchored. The PMPA can efficiently catalyze the 4‐nitrophenol (4‐NP) reduction, with a reaction rate constant of 9.5 × 10−3 s−1 (and 1067.4 s−1 g−1), which is highly competitive to the previously reported high‐performance Ag NPs catalysts. This is probably due to the favorable mass/electron conduction of 3D porous structure and strong interaction between PA and Ag. Moreover, the magnetism renders PMPA recyclability via a simple magnetic attraction, and the reaction rate constant remains at a high level after six reuse cycles, up to 4.8 × 10−3 s−1. This work highlights the important role of 3D porous PANI in structure of Ag NPs nanocomposites, and paves a new way to develop recyclable catalysts with facile preparation and high catalytic performance.Highlights Facile synthesis via in situ reaction between 3D porous PANI and AgNO3. Stable dispersion and strong anchor attributed to phytic acid. Conductive porous structure to facilitate mass/electron transportation. Outstanding catalytic performance for 4‐NP reduction and recycle by magnetism.

EHydrogenation: Hydrogen‐free Electrochemical Hydrogenation

AbstractHydrogenation reactions are staple transformations commonly used across scientific fields to synthesise pharmaceuticals, natural products, and various functional materials. However, the vast majority of these reactions require the use of a toxic and costly catalyst leading to unpractical, hazardous and often functionally limited conditions. Herein, we report a new, general, practical, efficient, mild and high‐yielding hydrogen‐free electrochemical method for the reduction of alkene, alkyne, nitro and azido groups. Finally, this method has been applied to deuterium labelling.

EHydrogenation: Hydrogen-free Electrochemical Hydrogenation.

Hydrogenation reactions are staple transformations commonly used across scientific fields to synthesise pharmaceuticals, natural products, and various functional materials. However, the vast majority of these reactions require the use of a toxic and costly catalyst leading to unpractical, hazardous and often functionally limited conditions. Herein, we report a new, general, practical, efficient, mild and high-yielding hydrogen-free electrochemical method for the reduction of alkene, alkyne, nitro and azido groups. Finally, this method has been applied to deuterium labelling.

Heterogeneous V2O5/TiO2-Mediated Photocatalytic Reduction of Nitro Compounds to the Corresponding Amines under Visible Light.

The hydrogenation of nitro compounds to their corresponding amines is developed using a heterogeneous and recyclable catalyst (V2O5/TiO2) under irradiation of blue LED (9 W) at ambient temperature. Hydrazine hydrate is used as a reductant and ethanol is used as a solvent, facilitating green, sustainable, low-cost production. The synthesis of 32 (hetero)arylamines and their pharmaceutically relevant molecules (five) are described. Significant features of the protocol include catalyst recyclability, green solvent, ambient temperature, and gram-scale reactions. Among the other aspects studied are 1H-NMR-assisted reaction progress monitoring, control experiments for mechanistic studies, protocol applications, and recyclability studies. Furthermore, the developed protocol enabled wide functional group tolerance, chemo-selectivity, high yield, and low-cost, sustainable, and environmentally benign synthesis.

Step-Economic Total Synthesis of Melosatin A from Eugenol.

An efficient and straightforward route toward the isatin-type natural product melosatin A is reported, employing a trisubstituted aniline as a key intermediate. The latter was synthesized in 4 steps and 60% overall yield from eugenol, through its regioselective nitration, sequentially followed by a Williamson methylation, an olefin cross-metathesis with 4-phenyl-1-butene and the simultaneous reduction of olefin and nitro groups. The final step, a Martinet cyclocondensation of the key aniline with diethyl 2-ketomalonate, provided the natural product with 68% yield.

Realizing the Continuous Chemoenzymatic Synthesis of Anilines Using an Immobilized Nitroreductase.

The use of biocatalysis for classically synthetic transformations has seen an increase in recent years, driven by the sustainability credentials bio-based approaches can offer the chemical industry. Despite this, the biocatalytic reduction of aromatic nitro compounds using nitroreductase biocatalysts has not received significant attention in the context of synthetic chemistry. Herein, a nitroreductase (NR-55) is demonstrated to complete aromatic nitro reduction in a continuous packed-bed reactor for the first time. Immobilization on an amino-functionalized resin with a glucose dehydrogenase (GDH-101) permits extended reuse of the immobilized system, all operating at room temperature and pressure in aqueous buffer. By transferring into flow, a continuous extraction module is incorporated, allowing the reaction and workup to be continuously undertaken in a single operation. This is extended to showcase a closed-loop aqueous phase, permitting reuse of the contained cofactors, with a productivity of >10 gproduct gNR-55-1 and milligram isolated yields >50% for the product anilines. This facile method removes the need for high-pressure hydrogen gas and precious-metal catalysts and proceeds with high chemoselectivity in the presence of hydrogenation-labile halides. Application of this continuous biocatalytic methodology to panels of aryl nitro compounds could offer a sustainable approach to its energy and resource-intensive precious-metal-catalyzed counterpart.

ZVI-Mediated High-Rate Nitrogen Removal from Fulvic Acid (FA)-Containing Wastewater by Anammox: Revealing the Genomic and Molecular Level Mechanisms

The anammox-based technologies are generally inhibited by refractory dissolved organic matter (rDOM), which is ubiquitous in real wastewater. In this study, a novel cost-effective approach, namely, zero-valent iron (ZVI) treatment, was presented to alleviate such inhibitory effects. The results showed that ZVI mitigated the inhibition of fulvic acids (FA) to anammox. Due to the 2 g/L ZVI addition, the nitrogen removal efficiency (NRE) increased from 83.53 to 90.06% when the FA concentration increased from 0 to 160 mg/L in wastewater. Additionally, the co-occurrence network linking Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and 16S rRNA sequencing results revealed the mechanism of ZVI mitigating inhibition by promoting the reduction of nitro and nitroso groups of FA and reshaping the metabolic division of functional bacteria. Hydrolytic acidifying bacteria (e.g., Anaerolineaceae and Ignavibacterium) were enriched for FA degradation, which was ultimately beneficial for denitrifying bacteria and anaerobic ammonium oxidation bacteria (AnAOB). Furthermore, metagenomics revealed that ZVI stimulated multiple nitrogen removal formed by anammox, denitrification, and DNRA by accelerating extracellular electron transfer resorting to FA serving as an electron shuttle and upregulating functional genes encoding electron generation, transport, and consumption processes.

Bio-mediated synthesis of CuO nano bundles from Gomutra (cow urine): Synthesis, characterization, photodegradation of the malachite green dye and SBH mediated reduction of 4-nitrophenol

We synthesized CuO nano bundles-like structures from Gomutra (cow urine). Urea and uric acid, which are present in the gomutra, act as reducing and capping agents, resulting in unique CuO nano bundles-like structure formation. No such morphological formation was observed from synthetic urea. X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDAX), UV–Visible, Fourier transforms infrared (FT-IR), Brunauer -Emmett-Teller (BET), and (photoluminescence) PL-Spectrofluorometer were used to analyze bio-mediated synthesized CuO nano bundle-like structures. From XRD analysis, the CuO nano bundle exhibits a monoclinic system with an average crystalline size of 15.76 nm. SEM results signified nano bacillus-like structures, resembling nano bundle-like designs in aggregate. EDAX anticipated the presence of only Cu and O atoms. FT-IR validates the existence of Cu and O bonds. The band gap was calculated using the DRS [Diffused reflectance mode] technique, and the value was found to be 1.29 eV. The BET and BJH [Barret-Joyner-Halenda] analysis estimated the surface area and pore size to be 28.24 Cm3/g and 11.5 nm. Intense emission peaks are seen at 465 nm from the PL spectrometer. Electron-hole transfer behavior in CuO nano bundles stemmed from Electrochemical impedance spectroscopy (EIS technique). The photocatalytic performance of malachite Green was examined in an aqueous medium, and degradation efficiency was found to be 98.2% in 70 min [min] with a rate constant of 0.0303 min−1. The catalyst ensured good activity for up to five cycles and was also found to be stable from SEM and XRD results. In addition, intermediated products were analyzed by the LC-MS, Electron Spin Resonance (ESR), and TOC [Total organic carbon] techniques. Required supporting evidence was elucidated in the Schematic pathway. CuO nano bundles also exhibited good catalytic behavior for reducing 4-nitrophenol in the ultrasonication method at room temperature with the whole reduction of nitro groups was proven by UV– Visible, FT-IR, and LC-MS technique, and the rate constant was found to be 0.3142 min−1. The present result clearly highlights that CuO nano bundles synthesized using gomutra can play a critical role in removing hazardous dyes from effluents of textile and dye industries. Further expanding the application of these nano bundles will promote an effective complementary and alternative strategy for treating refractory pollutants from wastewater.

Highly Efficient Catalytic Reduction of Nitrobenzene Using Cu@C Based on a Novel Cu–MOF Precursor

Currently, the catalytic reduction of nitrobenzene requires more efficient and low-cost catalysts. In this work, a new copper-based metal-organic framework (MOF) was designed by the calcination of Cu–MOF at 700 °C (denoted as Cu@C). The catalyst showed superior catalytic performance toward the reduction of nitrobenzene, using sodium borohydride (NaBH4) as the reducing agent, and the catalyst exhibited high nitrobenzene conversion (100%) and a quick reaction time (8 min). This was one of the highest efficiencies among non-noble metal catalysts reported so far, as general non-noble metal catalysts typically require more than 15 min. This catalyst had excellent acid resistance after etching using sulfuric acid (H2SO4) for 24 h with a nitrobenzene conversion rate that was still more than 90%. In addition, it could be used more than five times and the catalytic properties remained essentially unchanged, without any reactivation treatment. Therefore, this study could offer a new efficient non-noble metal catalyst for the reduction of nitro compounds.

Metal-Free Supramolecular Reduction of Nitro Compounds into the Cucurbit[7]uril Cavity: Testing the Enabling Technique in Aqueous Media

Metal-Free Supramolecular Reduction of Nitro Compounds into the Cucurbit[7]uril Cavity: Testing the Enabling Technique in Aqueous Media

Ru(II) and Ru(III) complexes containing N‐acylthiourea ligands: Supramolecular structures and synthons, reduction, and reaction pathway of aromatic nitro compounds

Four ruthenium complexes {[RuCl(CO)(PPh3)2L1], [RuCl(CO)(PPh3)2L2], [RuCl2(PPh3)2L1] and [RuCl2(PPh3)2L2]} supported with N‐acylthiourea‐based ligands were synthesized. The compounds prepared were characterized by 1H NMR, 13C NMR, elemental analysis, UV–vis, and magnetic susceptibility methods. The characterization of the molecular structure of two ruthenium complexes {[RuCl(CO)(PPh3)2L1] and [RuCl2(PPh3)2L1]} was also performed using the single crystal X‐ray diffraction method. Single crystal X‐ray analyses indicates the existence of different non‐covalent interactions between different parts of the molecules, which led to the formation of three‐dimensional supramolecular architectures and synthons. The magnetic susceptibility and UV‐vis spectra of the prepared ruthenium complexes propose that they are of low‐spin states, where Ru(II) is d6 and Ru(III) is d5 low spin. These ruthenium compounds functioned as catalysts for the NaBH4‐mediated reduction of various nitro compounds. The catalytic results show that the [RuCl2(PPh3)2L] type complexes exhibit higher catalytic activity than the [RuCl(CO)(PPh3)2L] type complexes, and [RuCl2(PPh3)2L1] has high catalytic selectivity and efficiency in a short time (>99 yield with catalyst loading 0.01 mol in 0.5 h). Furthermore, the catalytic activity of [RuCl2(PPh3)2L1] was investigated using nitrobenzene as a model substrate to understand the reaction pathway, and this study proved that this nitro reduction proceeds via a direct pathway, with the formation of N‐hydroxylamine as the main intermediate followed by the occurrence of aniline.

Cytochrome P450 in GtoPdb v.2023.1

The cytochrome P450 enzyme superfamily (CYP), E.C. 1.14.-.-, are haem-containing monooxygenases with a vast range of both endogenous and exogenous substrates. These include sterols, fatty acids, eicosanoids, fat-soluble vitamins, hormones, pesticides and carcinogens as well as drugs. Listed below are the human enzymes, their relationship with rodent CYP enzyme activities is obscure in that the species orthologue may not metabolise the same substrates. Some of the CYP enzymes located in the liver are particularly important for drug metabolism, both hepatic and extrahepatic CYP enzymes also contribute to patho/physiological processes. Genetic variation of CYP isoforms is widespread and likely underlies a proportion of individual variation in drug disposition. The superfamily has the root symbol CYP, followed by a number to indicate the family, a capital letter for the subfamily with a numeral for the individual enzyme. Some CYP are able to metabolise multiple substrates, others are oligo- or mono- specific. CYP also catalyse diverse oxidation and reduction reactions. These include ring hydroxylation, N-oxidation, sulfoxidation, epoxidation, the dealkylation of N-, S- and O- moieties, desulfation, deamination, as well as reduction of azo, nitro and N-oxide groups.

Graphene Nanoribbons/Manganese Oxide Nanocomposite Modified Electrode for Detection of Antimicrobial Drug Nitrofurantoin

The design and development of a new kind of cost-effective electrode material with excellent selectivity and stability are still a great challenge in the field of electrochemical sensors. Recently, researchers have paid more attention to the electrochemical reduction of nitro compounds due to their hazardous nature. Nitro compounds play a vital role in various industrial applications. However, the direct discharge of nitro compounds to the environment as industrial wastewater is harmful. In this study, a nanocomposite made of 1D graphene nanoribbons decorated with manganese dioxide (GNR-MnO2) was prepared to fabricate an electrochemical transducer for the determination of nitrofurantoin (NFT) in biofluids. First, 1D GNR was prepared by unzipping of multiwalled carbon nanotubes. Second, the GNR was decorated with MnO2 by the hydrothermal reduction method. As-prepared GNR-MnO2 nanocomposite was comprehensively characterized by field emission scanning electron microscopy with EDX, XRD, UV–visible, electrochemical impedance spectroscopy, and cyclic voltammetry. Moreover, GNR-MnO2-coated glassy carbon electrode (GCE) exhibited good electrocatalytic activity toward NFT. The electroreduction of NFT was found at −0.40 V which was 50 mV lower than bare GCE. GNR-MnO2 nanocomposite modified GCE showed a well-defined linear reduction peak current for NFT from 10 nM to 1,000 µM. The selectivity of the sensor was also analyzed in the presence of other nitro compounds which confirmed that NFT can be selectively detected at −0.4 V. The GNR-MnO2 modified electrode was also able to separate reduction peaks of other nitro compounds. In addition, the detection of NFT was carried out in human urine samples with a good recovery of 99.60%–98.60%.

Structural Modification in Au-MoS2 Quantum Dot Composites for Improved Catalytic Efficiency in p-Nitrophenol Reduction

Au-MoS2 quantum dots (QDs) composites are ideal catalysts for a number of reactions, including the reduction of p-nitrophenol (PNP). However, the structural role of Au-MoS2 QDs composites in their catalytic efficiency has never been investigated. In this work, a comparative study is carried out to investigate the catalytic reactivities of a gold nanorod–molybdenum disulfide quantum dots (AuNR-MoS2 QDs) composite and a gold nanosphere–molybdenum disulfide quantum dots (AuNS-MoS2 QDs) composite. In addition, the catalytic reactivities of a gold nanorod (AuNR) and a gold nanosphere (AuNS) are also studied. The catalytic efficiency of the as-prepared composites is then investigated for the reduction of p-nitrophenol, taken as the model reaction. The kinetics of the catalytic reduction of p-nitrophenol reveal that the AuNR-MoS2 QDs composite demonstrates the highest catalytic efficiency, having a rate constant of 0.06 min–1, compared to the AuNS-MoS2 QDs composite, AuNR, and AuNS, having a rate constant of 0.023, 0.021, and 0.008 min–1, respectively. The possible mechanism is also discussed in the paper. Finite difference time domain (FDTD) simulation was carried out to simulate the electric field intensity of the AuNR-MoS2 QDs composite, AuNS-MoS2 QDs composite, AuNR, and AuNS. It is observed that, in general, the electric field intensity increases for the AuNR-MoS2 QDs and AuNS-MoS2 QDs composites when compared with only AuNR and AuNS. Therefore, this study emphasizes understanding the structural role of AuNR-MoS2 QDs and AuNS-MoS2 QDs composites, which is paramount in evaluating the catalytic efficiencies as demonstrated in the reduction of aromatic nitro compounds.

Decoration of ruthenium nanoparticles on nitrogen and phosphorus-doped carbon as a robust catalyst for the reduction of nitroarenes

Ruthenium nanoparticles (NPs) were decorated on nitrogen and phosphorus-doped carbon derived from phosphorus zeolitic imidazolate frameworks (P-ZIFs) via a facile in-situ doping-carbonization method. As-synthesized nanostructures were used as a heterogeneous catalyst for the chemoselective reduction of aromatic nitro compounds to the corresponding amines under ambient conditions. In contrast, P-ZIF-8 and P-ZIF-67-derived catalysts showed poor activity, while P-BMZIF-derived catalyst demonstrated high catalytic activity. Also, it was found that phosphorus on carbon layers improved catalytic efficiency when added to the carbon layers

Pd nanoparticles decorated on Schiff base-modified chitosan/CeO2 as a heterogeneous and retriable nanocatalyst for Heck reactions and remediation of environmental pollutants

In this paper, we have developed a novel, highly active, eco-friendly, and versatile heterogeneous catalyst system in which Pd nanoparticles are decorated on Schiff base-modified chitosan‑cerium oxide particles (Pd@CS-CeO2). In order to confirm the successful fabrication of Pd@CS-CeO2, FTIR, XRD, SEM, TEM, BET, TG/DTG, and EDS analyses were performed, and its performance was evaluated as a heterogeneous nanocatalyst in Heck coupling reaction and reduction of nitro compounds. The catalytic tests showed that the desired Heck products were readily produced by Pd@CS-CeO2 without being contaminated with the aryl iodides, bromides, and chlorides. Moreover, different nitro compounds were efficiently reduced to corresponding amino compounds by Pd@CS-CeO2 within 95–160 s. Thanks to the heterogeneous nature of Pd@CS-CeO2 catalyst, it was easily recovered via simple filtration and reused up to 5 successive runs by giving 88 % yield. Due to its good catalytic and reusability performance together with stability/durability, Pd@CS-CeO2 is promising candidate as a catalyst for various catalytic or organic reactions.

Fabrication of recyclable magnetic Fe3O4–SiO2–Cu2O/Cu core–shell nano-catalyst for high-efficient reduction of aromatic nitro compound

Fabrication of recyclable magnetic Fe3O4–SiO2–Cu2O/Cu core–shell nano-catalyst for high-efficient reduction of aromatic nitro compound

Unusual impurity formation during the process development of Olsalazine sodium leads to a new efficient and economical synthesis of tricaine mesylate

An impurity formation during the nitro group reduction for the synthesis of Olsalazine Sodium API, which was later explored for the development of a short and efficient manufacturing process for tricaine mesylate is reported here. The highlight of the synthesis is, during the nitro group reduction, the deoxygenation occurs forming the core of tricaine and the leaving mesyloxy group serves as a counter anion furnishing the tricaine mesylate in one step. The reported process here circumvents the need for isolation of the free base and a separate salt formation step, thus it is more economical and efficient. This article is protected by copyright. All rights reserved.

CHEMICAL PROPERTIES AND APPLICATIONS OF NITROPYRIDINES

Background. Pyridines are one of the most common heterocycles, the derivatives of which are widely used in pharmaceuticals, agrochemistry, and also in the production of new materials. Therefore, a comprehensive study of the chemical behavior of various pyridine derivatives will continue to be an urgent task of organic chemistry. This literature review is devoted to the systematization and analysis of the chemical properties of pyridine nitro derivatives, starting from the first half of the 20th century and up to the present. The paper considers both reactions proceeding through the nitro group (reduction under the action of various chemical agents, substitution, condensation) and reactions through the pyridine cycle. The main areas of application of nitropyridines are also shown.
 Purpose. Generalize and systematize the main types of reactions characteristic of nitropyridines, show the features of their chemical properties associated with the transformation of the nitro group, its effect on the mobility of substituents in the pyridine ring, as well as on the activity of the heterocycle as a whole.
 Materials and methods. To achieve the goal of the study, a review of the scientific literature was made on the main types of chemical reactions characteristic of pyridine nitro derivatives and the most significant areas of their application.
 Results. This paper summarizes the results of experimental studies on the chemical properties and application of nitropyridines from the beginning of the last century to the present.
 Conclusion. Thus, as a result of the analysis of sources devoted to the chemical properties and application of nitropyridines, a brief literature review was compiled, including the main types of reactions characteristic of the compounds under study, and their main areas of application were identified.

WS2-Nanosheet-Modified Electrodes as an Efficient Electrochemical Sensing Platform for the Nonenzymatic Detection of the Insecticide Imidacloprid.

Imidacloprid (IMI) is a systemic insecticide, which is widely used for seed treatment and pest control in vegetables. The unwarranted presence of traces of IMI in vegetables and groundwater is a matter of grave concern which needs to be detected and quantified in order to effect remedial measures for the sake of food safety. In this work, we communicate the fabrication of tungsten sulfide (WS2) nanosheets and the construction of an amperometric sensor for the precise determination of IMI. The sensor performances were evaluated by using cyclic voltammetry (CV). The presence of surface-active sites and the fast electron transfer on WS2/GCE favored the electrochemical reduction of the aromatic nitro group in IMI. The developed IMI sensor displayed a linear range of IMI detection from 10 to 90 μM with a detection limit of 0.28 μM. The developed WS2/GCE sensor also displayed good sensitivity, with a value of 3.98 μA μM-1 cm-2. The electrochemical measurements demonstrated the superior selectivity of the constructed WS2/GCE sensor for IMI detection, which makes it suitable for practical applications.