N-heterocyclic Compounds Research Articles

Catalytic co-liquefaction of microalgae + corn straw over K3PO4+γ-Al2O3 supported Fe and Ni mono- / bimetallic in-situ composite catalysts for the production of liquid biofuel

In the present study, an array of K3PO4 + γ-Al2O3 supported Fe and Ni in-situ composite catalysts including K3PO4-Fe/γ-Al2O3, K3PO4-Ni/γ-Al2O3, K3PO4-Fe-Ni/γ-Al2O3 were prepared and characterized by Nitrogen-physisorption, XRD, XPS, NH3-TPD, H2-TPR, SEM, and TEM analysis. The effects of catalyst type, catalysts loading, feedstock loading and the ratio between corn straw and spirulina on the products yield and distribution from co-hydrothermal liquefaction of spirulina and corn straw were investigated. The greater specific surface area, larger amount of medium acid sites, the key roles of K and Fe-Ni bimetallic system and enhanced interaction between Fe, Ni and γ-Al2O3 support of K3PO4-Fe-Ni/γ-Al2O3 are mainly responsible for the greatest amount of water-insoluble (35.73 wt%) and water-soluble (2.18 wt%) biocrude. Besides, the optimal reaction condition (5 wt% catalysts loading, 10 wt% feedstock loading and spirulina: corn straw = 1:1 w/w) was confirmed. The presence of catalysts especially for K3PO4-Fe-Ni/γ-Al2O3 significantly increased the energy recovery of biocrude. Meanwhile, K3PO4-Fe-Ni/γ-Al2O3 noticeably increased the fraction of lighter molecule in biocrude up to 57.18 wt%. The esters, phenols and N-heterocyclic compounds were found to be dominated in biocrude from all co-HTL cases, and the enhanced selectivity to esters with catalysts were observed. Finally, the prospective reaction pathway and mechanism of the catalytic co-HTL of spirulina and corn straw was proposed and discussed detailly and comprehensively.

Novel 5-bromoindole-2-carboxylic Acid Derivatives as EGFR Inhibitors: Synthesis, Docking Study, and Structure Activity Relationship.

The indole backbone is encountered in a class of N-heterocyclic compounds with physiological and pharmacological effects such as anti-cancer, anti-diabetic, and anti-HIV. These compounds are becoming increasingly popular in organic, medicinal, and pharmaceutical research. Nitrogen compounds' hydrogen bonding, dipole- dipole interactions, hydrophobic effects, Van der Waals forces, and stacking interactions have increased their relevance in pharmaceutical chemistry due to their improved solubility. Indole derivatives, such as carbothioamide, oxadiazole, and triazole, have been reported to act as anti-cancer drugs due to their ability to disrupt the mitotic spindle and prevent human cancer cell proliferation, expansion, and invasion. To synthesize new 5-bromoindole-2-carboxylic acid derivatives that function as EGFR tyrosine kinase inhibitors as deduced through molecular docking studies. Different derivatives of indole (carbothioamide, oxadiazole, tetrahydro pyridazine-3,6-dione, and triazole) were synthesized and evaluated through different chemical, spectroscopic methods (IR, 1HNMR, 13CNMR, and MS) and assessed in silico and in vitro for their antiproliferative activities against A549, HepG2, and MCF-7 cancer cell lines. According to molecular docking analyses, compounds 3a, 3b, 3f, and 7 exhibited the strongest EGFR tyrosine kinase domain binding energies. In comparison to erlotinib, which displayed some hepatotoxicity, all of the evaluated ligands displayed good in silico absorption levels, did not appear to be cytochrome P450 inhibitors, and were not hepatotoxic. The new indole derivatives were found to decrease cell growth of three different types of human cancer cell lines (HepG2, A549, and MCF-7), with compound 3a being the most powerful while still being cancer-specific. Cell cycle arrest and the activation of apoptosis were the results of compound 3a's inhibition of EGFR tyrosine kinase activity. The novel indole derivatives, compound 3a in particular, are promising anti-cancer agents which inhibit cell proliferation by inhibiting EGFR tyrosine kinase activity.

On the Current Status of Ullmann-Type N-Arylation Reactions Promoted by Heterogeneous Catalysts

Ullmann-type C–N heterocoupling reactions have been applied for the syntheses of N-arylated amines. In the past decade, transition metal-catalyzed N-arylations have been recognized as particularly efficient procedures for the preparation of nitrogen-containing aromatic systems. These reactions typically carried out under optimized conditions, have also been found to be suitable for the synthesis of complex molecules with other functional groups, including natural products, drugs, or pharmaceuticals. Most importantly, copper-catalyzed N-arylations have been studied and employed in the total synthesis of biologically active compounds. The construction of fused N-heterocyclic compounds also remained the subject of extensive research because of their potential applications in drug discovery and the development of functional materials. The aim of this review is to summarize the recent progress in the synthetic applications of Ullmann-type N-arylation reactions performed in heterogeneous systems. In particular, the utilization of copper and palladium species immobilized on various support materials, modified by surface functionalization, has been discussed and evaluated.

Recent Advances in the Green Synthesis of Active N-Heterocycles and Their Biological Activities.

N-heterocyclic scaffolds represent a privileged architecture in the process of drug design and development. It has widespread occurrence in synthetic and natural products, either those that are established or progressing as potent drug candidates. Additionally, numerous novel N-heterocyclic analogues with remarkable physiological significance and extended pharmaceutical applications are escalating progressively. Hence, the classical synthetic protocols need to be improvised according to modern requirements for efficient and eco-friendly approaches. Numerous methodologies and technologies emerged to address the green and sustainable production of various pharmaceutically and medicinally important N-heterocyclic compounds in last few years. In this context, the current review unveils greener alternatives for direct access to categorically differentiated N-heterocyclic derivatives and its application in the establishment of biologically active potent molecules for drug design. The green and sustainable methods accentuated in this review includes microwave-assisted reactions, solvent-free approaches, heterogeneous catalysis, ultrasound reactions, and biocatalysis.

Mechanistic insights into the ROS-mediated inactivation of human aldehyde oxidase.

Human aldehyde oxidase (hAOX1) is a molybdoenzyme that oxidizes aldehydes and N-heterocyclic compounds, thereby generating hydrogen peroxide (H2 O2 ) and superoxide during turnover. hAOX1 has been shown previously to be inactivated under turnover conditions by H2 O2 . Here, we investigated the effect of exogenously added H2 O2 on the activity of hAOX1. We show that exogenously added H2 O2 did not affect the enzyme activity under aerobic conditions, but completely inactivated the enzyme under anaerobic conditions. We propose that this effect is based on the reducing power of H2 O2 and the susceptibility of the reduced molybdenum cofactor (Moco) to lose the sulfido ligand. When oxygen is present, the enzyme is rapidly reoxidized. We believe that our study is significant in understanding the detailed effect of reactive oxygen species on the inactivation of hAOX1 and other molybdoenzymes.

Multifaceted Chiral Probe 2,3-Dihydro-4-hydroxy-chromene Schiff Base in Detecting Cu2+ Ions, l-Histidine, and Indazole: Spectroscopic Investigation and Confocal and Live Cell Imaging.

2,3-Dihydro-4-hydroxy-chromene-4(N)-ethyl thiosemicarbazone (probe F4) is used as a chemosensor, and it selectively detected Cu2+ ions among the metal ions by showing fluorescence "TURN ON" behavior. The stoichiometric binding of the probe with Cu2+ (CF4) was confirmed by Job's plot and mass spectroscopy. Further, CF4 was used as a sensor for the detection of l-amino acids and N-heterocyclic compounds. Among them, CF4 selectively detected l-histidine by showing fluorescence "TURN-OFF" behavior and selectively detected indazole by showing fluorescence "TURN-ON" behavior. These behaviors were further confirmed by in vivo live cell imaging studies by using Caenorhabditis elegans as a model. In vitro cytotoxicity was assayed for probe F4, complex CF4, and CF4 with l-histidine and indazole. The IC50 concentration was used for confocal imaging studies by using the MDA-MB-231 cell line (breast cancer cell line).

Which microorganisms contribute to mousy off-flavour in our wines?

In recent years, the frequency of occurrence of mousy off-flavours in wines has increased. This could be caused by the significant decrease in sulphur dioxide addition during processing, the increase in pH or even the trend for spontaneous fermentation in wine. This off-flavour was associated with Brettanomyces bruxellensis or lactic acid bacteria metabolisms. Three N-heterocyclic compounds (APY, ETHP, ATHP) were described as involved in mousiness perception. Thus far, no study addressed the variability in that N-heterocycles production according to microorganism strains from different species. Twenty-five wines presenting mousy off-flavour were analysed. In total, 252 bacteria with 90.5 % of Oenococcus oeni and 101 yeast strains with 53.5 % of Saccharomyces cerevisiae were isolated and identified. Their capacity to produce mousy compounds was investigated using Stir Bar Sorptive Extraction-Gas Chromatography-Mass Spectrometry (SBSE-GC-MS) and a standardised N-heterocycle assay medium. While four and three species of yeast and bacteria, respectively, were isolated from mousy wines, only three species of microorganisms were associated with N-heterocycles production: B. bruxellensis, Lentilactobacillus hilgardii and Oenococcus oeni. The screening was then extended to collection strains for these three species to improve their genetic representativity. Our results show that the levels and the ratios of the three N-heterocycles present huge variations according to the species. In addition, it has been shown that in most mousy wines, B. bruxellensis was not found. Finally, an interesting correlation between ATHP and ETHP was identified.

Incorporating hydrothermal liquefaction into wastewater treatment – Part III: Aqueous phase characterization and evaluation of on-site treatment

For the incorporation of the hydrothermal liquefaction (HTL) process into wastewater treatment plants (WWTPs), the liquid by-product of the process, named HTL aqueous, creates the biggest bottleneck because of its high volume and contaminant levels. In this study, an extensive characterization of various HTL aqueous samples, obtained from the liquefaction of mixed sludge cake at 290–360 °C and 0–30 min, was performed. From the most to least abundant, compounds found in HTL aqueous samples were N-heterocyclics, volatile fatty acids (VFAs), amides, ketones, amines, and phenolics. The characteristics that make HTL aqueous suitable for biological treatment were pH, alkalinity, macro- and micro-nutrients. However, along with N-heterocyclic compounds, total ammonia levels of 3.9–7.1 g/L and total phenol levels of 1.5–2.3 g/L were identified as compounds that would potentially inhibit biological treatment processes. The chemical oxygen demand (COD) levels of HTL aqueous samples were 87–103 g/L. HTL aqueous obtained under 325 °C-0 min (no retention at 325 °C) condition was identified as the most suitable for biological treatment owing to its high VFA (17 g/L), carbohydrate (827 mg/L), and low phenol (1.6 g/L) concentrations. By increasing HTL reaction severity (temperature and retention time), COD, dissolved protein, total carbohydrate, total phenol, and total short-chain VFA levels decreased, whereas total ammonia, pH, alkalinity, valeric acid, and iso-valeric acid concentrations increased. Regression analysis was used to obtain equations that reveal patterns between HTL reaction parameters and aqueous phase characteristics. Overall, a pretreatment application was found necessary for the detoxification of HTL aqueous before biological treatment.

Microalgae fractionation and pyrolysis of extracted microalgae biopolymers

In order to maximize the economic return from microalgae production, the feasibility of thermochemically converting microalgae by-products which have had one or more biochemical components extracted (lipids and/or protein) needs to be considered. The extracted microalgae are waste stemming from microalgae biorefineries where biodiesel and/or valuable proteins/peptides have been produced. The biorefinery scheme of maximized microalgae utilization based on isolation of lipids or lipids and proteins combined, and the thermochemical conversion of the remaining fractions are discussed in this study. The biopolymer components of Nannochloropsis gaditana were extracted to form a lipid fraction, a protein fraction and a carbohydrate-rich residue. The lipid extraction efficiency reached 76.9 wt.%, however, the efficiency of protein extraction was 42.2 wt.% due to the inability of the extraction process to remove all protein. The surface functional groups and thermochemical characteristics of extracted components were investigated by FTIR and py-GC/MS, respectively. The FTIR results suggested that the extraction process disrupted the microalgae cell walls and released intracellular components. Lipids are recommended to be extracted for biofuel production by transesterification. For specific high protein-containing microalgae, protein extraction has to be considered to obtain high value proteins and derived chemicals. After the extraction of high value products, the carbohydrate-rich residue which is considered of low value, can be used as a fast pyrolysis feedstock instead of the whole microalgae. The pyrolysis chemical pathways as a function of temperature were schematized in order to better understand the reaction mechanisms in microalgae pyrolysis. The formation of alkanes and alkenes at higher temperatures were stemming from the long-chain alcohols and carboxylic acids. The formation pathways of N-heterocyclic compounds include Maillard reactions, cracking of amino acids and the cyclization of amines and amides.

Mechanism of the Multistep Catalytic Cycle of 6-Hydroxynicotinate 3-Monooxygenase Revealed by Global Kinetic Analysis

The class A flavoenzyme 6-hydroxynicotinate 3-monooxygenase (NicC) catalyzes a rare decarboxylative hydroxylation reaction in the degradation of nicotinate by aerobic bacteria. While the structure and critical residues involved in catalysis have been reported, the mechanism of this multistep enzyme has yet to be determined. A kinetic understanding of the NicC mechanism would enable comparison to other phenolic hydroxylases and illuminate its bioengineering potential for remediation of N-heterocyclic aromatic compounds. Toward these goals, transient state kinetic analyses by stopped-flow spectrophotometry were utilized to follow rapid changes in flavoenzyme absorbance spectra during all three stages of NicC catalysis: (1) 6-HNA binding; (2) NADH binding and FAD reduction; and (3) O2 binding with C4a-adduct formation, substrate hydroxylation, and FAD regeneration. Global kinetic simulations by numeric integration were used to supplement analytical fitting of time-resolved data and establish a kinetic mechanism. Results indicate that 6-HNA binding is a two-step process that substantially increases the affinity of NicC for NADH and enables the formation of a charge-transfer-complex intermediate to enhance the rate of flavin reduction. Singular value decomposition of the time-resolved spectra during the reaction of the substrate-bound, reduced enzyme with dioxygen provides evidence for the involvement of C4a-hydroperoxy-flavin and C4a-hydroxy-flavin intermediates in NicC catalysis. Global analysis of the full kinetic mechanism suggests that steady-state catalytic turnover is partially limited by substrate hydroxylation and C4a-hydroxy-flavin dehydration to regenerate the flavoenzyme. Insights gleaned from the kinetic model and determined microscopic rate constants provide a fundamental basis for understanding NicC's substrate specificity and reactivity.

Volatile Compound Analysis to Authenticate the Geographical Origin of Arabica and Robusta Espresso Coffee

The traceability of the geographical origin of coffee is a challenging issue to protect producers and consumers from the risk of fraud. A total of 162 Arabica from Peru, Colombia and Brazil, and Robusta from India, Vietnam and Uganda, espresso coffee (EC) samples of different degrees of roasting (light, medium and dark) were characterized for physico-chemical features (lipids, solids, and chlorogenic acids) and analyzed via SHS-GC/MS analysis, with the aim of discriminating the samples according to their geographical origin. Linear discriminant analysis (LDA), performed on the data of the chemical classes of the volatile organic compounds (VOCs), was able to correctly identify 97.53% of the tested samples through cross-validation. The dark roasting of the coffee beans implied a higher quantity of volatile compounds in the headspace of the EC, belonging to chemical classes of furans, esters, N-heterocyclic and sulfur compounds, reducing the differences by geographical origin. Light- and medium-roasted Robusta EC showed a major contribution of pyrazines and pyrimidines, while aldehydes, alcohols and ketones were generally more representative in Arabica samples. The quantitative distribution of volatile compounds proved to be a useful tool to discriminate samples by geographical origin.

Chirality Sensing of N-Heterocycles via 19F NMR.

Methods to rapidly detect and differentiate chiral N-heterocyclic compounds become increasingly important owing to the widespread application of N-heterocycles in drug discovery and materials science. We herein report a 19F NMR-based chemosensing approach for the prompt enantioanalysis of various N-heterocycles, where the dynamic binding between the analytes and a chiral 19F-labeled palladium probe create characteristic 19F NMR signals assignable to each enantiomer. The open binding site of the probe allows the effective recognition of bulky analytes that are otherwise difficult to detect. The chirality center distal to the binding site is found sufficient for the probe to discriminate the stereoconfiguration of the analyte. The utility of the method in the screening of reaction conditions for the asymmetric synthesis of lansoprazole is demonstrated.

An efficient synthetic route of quinoxalines from diols catalyzed by [RuCl2(p-cymene)]2/1,4-bis(diphenylphosphino)butane

An efficient and convenient homogeneous catalytic system is developed from commercially available Ru complex ([Ru(p-cymene)Cl2]2) and 1,4-bis(diphenylphosphino)butane (dppb) for coupling aromatic diamines and vicinal diols to produce quinoxaline derivatives, an important class of N-heterocycles, via one-step alcohol acceptorless dehydrogenation route. Under the optimized condition, quinoxaline derivatives are obtained in excellent yields (up to 93%) and high turnover numbers (up to 744). This homogeneous system for the synthesis of quinoxaline derivatives is performed under a practically neutral condition, and thus gives new threads to develop novel transition metal complexes for convenient and efficient synthesis of N-heterocycle compounds without the use of complicated ligand and stoichiometric amount of strong base, which are usually used in most reported homogeneous systems.

Liquid products of meat and bone meal pyrolysis: comprehensive assessment by chromatographic methods

Dorogov’s antiseptic stimulators (fractions 2 and 3) are products of meat and bone meal pyrolysis that are used to treat farm animals. However, there is a lack of detailed information about their chemical composition. We aimed to study individual compositions of organic substances in the water- and oil-soluble condensates of these preparations.
 Dorogov’s antiseptic stimulators ASD-2F and ASD-3F (Agrovetzashchita, Russia) were used as samples of the water- and oil-soluble condensates of meat and bone meal pyrolysis. Volatile substances were identified by gas chromatography and gas chromatography-mass spectrometry, while amino acids were determined by high-performance liquid chromatography.
 The initial water-soluble condensate contained ammonium salts, amides of carboxylic acids, N-heterocyclic compounds, hydantoins, amino acids, and dipeptides, with a total content of 8% of the condensate’s weight. Its dehydrated concentrate had almost no ammonium salts and amides of carboxylic acids, but its contents of hydantoins, amino acids, dipeptides, and lowvolatile nitrogen-containing heterocycles were 10–15 times as high as those in the initial condensate. The condensate contained 13 dipeptides and 19 amino acids with a total content of 2.5%. According to gas chromatography-mass spectrometry, the oilsoluble condensate contained over 30% of nitriles; 7–10% of higher and aromatic hydrocarbons, phenols, and amides (with esters); and 1–3% of N-heterocyclic compounds, naphthalenes, pyridines, and dipeptides. The nitrogen-containing heterocycles, as well as dipeptides, were similar to those in the water-soluble condensate.
 We identified 80% of individual organic substances in the water-soluble pyrolytic condensate. Together with its concentrate, they contained more than 220 organic substances divided into 10 main groups. The oil-soluble condensate consisted of over 350 individual organic compounds. The full composition of the preparations can be further identified by three-quadrupole liquid mass spectrometry.

Rhodococcus Strains from the Specialized Collection of Alkanotrophs for Biodegradation of Aromatic Compounds

The ability to degrade aromatic hydrocarbons, including (i) benzene, toluene, o-xylene, naphthalene, anthracene, phenanthrene, benzo[a]anthracene, and benzo[a]pyrene; (ii) polar substituted derivatives of benzene, including phenol and aniline; (iii) N-heterocyclic compounds, including pyridine; 2-, 3-, and 4-picolines; 2- and 6-lutidine; 2- and 4-hydroxypyridines; (iv) derivatives of aromatic acids, including coumarin, of 133 Rhodococcus strains from the Regional Specialized Collection of Alkanotrophic Microorganisms was demonstrated. The minimal inhibitory concentrations of these aromatic compounds for Rhodococcus varied in a wide range from 0.2 up to 50.0 mM. o-Xylene and polycyclic aromatic hydrocarbons (PAHs) were the less-toxic and preferred aromatic growth substrates. Rhodococcus bacteria introduced into the PAH-contaminated model soil resulted in a 43% removal of PAHs at an initial concentration 1 g/kg within 213 days, which was three times higher than that in the control soil. As a result of the analysis of biodegradation genes, metabolic pathways for aromatic hydrocarbons, phenol, and nitrogen-containing aromatic compounds in Rhodococcus, proceeding through the formation of catechol as a key metabolite with its following ortho-cleavage or via the hydrogenation of aromatic rings, were verified.

Anticooperativity and Competition in Some Cocrystals Featuring Iodine-Nitrogen Halogen Bonds.

Phenomena such as anticooperativity and competition among non-covalent bond donors and acceptors are key considerations when exploring the polymorphic and stoichiomorphic landscapes of binary and higher-order cocrystalline architectures. We describe the preparation of four cocrystals of 1,3,5-trifluoro-2,4,6-triiodobenzene with N-heterocyclic compounds, namely acridine, 3-aminopyridine, 4-methylaminopyridine, and 1,2-di(4-pyridyl)ethane. The cocrystals, which are characterized by single-crystal and powder X-ray diffraction experiments, all show moderately strong and directional iodine⋅⋅⋅nitrogen halogen bonds with reduced distance parameters ranging from 0.79 to 0.92 and carbon-iodine⋅⋅⋅nitrogen bond angles ranging from 165.4(3) to 175.31(7)°. The cocrystal comprising 1,3,5-trifluoro-2,4,6-triiodobenzene and acridine provides a relatively rare example where all three halogen bond donor sites form halogen bonds with three acceptor molecules, overcoming an anticooperative effect. This effect manifests itself through the lengthening of non-halogen-bonded C-I bonds, weakening their potential to form halogen bonds. The effect is only observed once two halogen bonds have been formed to 1,3,5-trifluoro-2,4,6-triiodobenzene; one such bond does not appear to be adequate. Among the four cocrystals studied, competition between the pyridyl nitrogen atoms and the amine nitrogen atoms suggests that the former are the preferred halogen bond acceptors. Analysis by Hirshfeld fingerprint plots and 13 C and 19 F magic-angle spinning solid-state nuclear magnetic resonance (NMR) spectroscopy provides additional insights into the prevalence of various short contacts in the crystal structures and into the spectral response to halogen-bond-induced cocrystallization.

π-Conjugated N-heterocyclic compound with redox-active quinone and pyrazine moieties as a high-capacity organic cathode for aqueous zinc-ion batteries

Organic cathode materials have been widely used for aqueous zinc-ion batteries (ZIBs) due to their designable molecular structures and diverse redox groups. However, there are still many challenges that need to be overcome, such as limited specific capacity and utilization, inadequate electrical conductivity, unsatisfactory cycle durability and unclear charge storage mechanism. Herein, we report a π-conjugated N-heterocyclic compound containing dual-redox active groups (i.e. quinone and pyrazine), benzo[b]phenazine-6,11-dione (BPD), which are employed as a cathode material in aqueous ZIBs. The BPD cathode shows a high capacity of up to 429 mAh g−1 at 0.05 A g−1, 100 % capacity utilization and excellent cycling performance upon 10,000 cycles. The aqueous ZIB full cell with the BPD cathode delivers an energy density of 276 Wh kg−1, higher than the most previously reported organic cathode materials. Moreover, ex-situ characterizations, electrochemical experiments, and theoretical calculations, clearly illustrate that H+ and Zn2+ are co-inserted during the charge/discharge process. The high utilization and stability of BPD cathode is due to the high insolubility of both BPD and its discharge products. This work provides a reasonable strategy and unique perspective for the design and synthesis of novel high-performance organic cathode materials for aqueous ZIBs.

N-Amidation of Nitrogen-Containing Heterocyclic Compounds: Can We Apply Enzymatic Tools?

Amide bond is often seen in value-added nitrogen-containing heterocyclic compounds, which can present promising chemical, biological, and pharmaceutical significance. However, current synthesis methods in the preparation of amide-containing N-heterocyclic compounds have low specificity (large amount of by-products) and efficiency. In this study, we focused on reviewing the feasible enzymes (nitrogen acetyltransferase, carboxylic acid reductase, lipase, and cutinase) for the amidation of N-heterocyclic compounds; summarizing their advantages and weakness in the specific applications; and further predicting candidate enzymes through in silico structure-functional analysis. For future prospects, current enzymes demand further engineering and improving for practical industrial applications and more enzymatic tools need to be explored and developed for a broader range of N-heterocyclic substrates.

Rational design of N-heterocyclic compound classes via regenerative cyclization of diamines

The discovery of reactions is a central topic in chemistry and especially interesting if access to compound classes, which have not yet been synthesized, is permitted. N-Heterocyclic compounds are very important due to their numerous applications in life and material science. We introduce here a consecutive three-component reaction, classes of N-heterocyclic compounds, and the associated synthesis concept (regenerative cyclisation). Our reaction starts with a diamine, which reacts with an amino alcohol via dehydrogenation, condensation, and cyclisation to form a new pair of amines that undergoes ring closure with an aldehyde, carbonyldiimidazole, or a dehydrogenated amino alcohol. Hydrogen is liberated in the first reaction step and the dehydrogenation catalyst used is based on manganese.

Nitrogen-containing Fused Heterocycles: Organic Synthesis and Applications as Potential Anticancer Agents

Abstract: The fused Nitrogen heterocyclic compounds and their derivatives have grown in prominence over the past several decades as a result of their significant medical value. The adaptable and easily synthesized N-Heterocyclic scaffolds are particularly exciting in both synthetic organic chemistry and the biological sector due to their powerful pharmacological properties, which are taken into consideration while considering their numerous uses. For the synthesis of N-heterocycles and their derivatives, several attempts were undertaken to create a variety of synthetic protocols. The N-Heterocyclic compounds provide a variety of adaptable structures for specific biological applications and represent novel, broad-spectrum antibacterial and anticancer agents. They typically have minimal toxicity profiles. The majority of these N-Heterocycles have demonstrated more cytotoxicity than the effective anticancer medication cisplatin. The design, synthesis, structural characterisation, and biological uses of N-Heterocycles are reviewed in this work. In this article, the developments made in this specific field are comprehensively examined.