Nitrogen Derivatives Research Articles

Synthesis of nitrogen and phosphorus-doped chitosan derivatives for enhanced flame retardancy, smoke suppression, and mechanical properties in epoxy resin composites.

Biomass-based flame retardants have attracted significant academic interest due to their environmental benefits and sustainability. Nevertheless, devising straightforward, eco-friendly, and mild methodologies to synthesize flame retardants of epoxy resins (EP) remains a formidable challenge. This paper reports the successful synthesis of a novel nitrogen and phosphorus-doped chitosan derivatives flame retardant (MMCA) utilizing phytic acid, chitosan, and melamine cyanurate via electrostatic self-assembly and physical encapsulation in an acidic aqueous solution. The incorporation of 5wt% MMCA into the EP readily achieved a UL-94V-0 rating. This improvement can be primarily attributed to the early formation of a continuous, dense, robust, and expanded char layer during combustion, coupled with the synergistic flame retardant mechanisms of radical scavenging and the dilution of non-combustible gases. Compared to pristine EP, EP/5MMCA exhibited significant reductions of 23.7%, 29.2%, and 24% in total smoke production rate, peak heat release rate, and peak smoke production rate, respectively. Moreover, the strategic introduction of MMCA also enhanced the glass transition temperature, storage modulus, and crosslinking density of EP, improving its tensile, compressive and impact properties. This study proposes a simple, viable, and environmentally sustainable strategy for the fabrication of biomass-based flame retardants, resulting in notable improvements the flame retardancy, smoke suppression, fire safety, and mechanical robustness of EP.

Phytochemical Constituent and Cumulative or Antagonistic Effects of Crops Plant Organ Combination on Free Radical Scavenging Capacity and Antioxidant Compound Content

Aims: In Burkina Faso, the majority of plant-based recipes are a combination of plant organs from the same or different species. For these recipes’ producers, the aim is to improve efficiency. However, our ethnobotanical surveys have revealed that for some species, efficacy is better when the species is not combined, or when it is combined in small proportions with other species. The aim of this study is to assess the effect of plant organ combination on free radical scavenging activity, phenolic compound content and flavonoid content. Study Design: The work combined harvesting and processing of plant material from September to November 2023, and laboratories analysis from January to March 2024 at Natural Substances Departement of Institut de Recherche en Sciences Appliquées et Technologie, Ouagadougou. Methodology: We prepared two batches of recipes, first combining two species from the same genus, then two species from different genera. The powder of each plant without combination was also used to compare data. Phytochemical screening was first carried out with TLC and LC-MS analysis on each plant extract. We then assessed the phenolic compound content (PCC) using Folin-Ciocalteu method, flavonoid content (FCC) using aluminum chloride test, antioxidant content using TEAC method and free radical scavenging activity using DPPH method, for different batches. Results: Phytochemical constituent in the three species are phenolic compounds, terpenoids and nitrogen derivatives. The results of biological property evaluation suggest that for best efficacy and to obtain a high phenolic compound content, Lippia multiflora leaves should be used separately, or combined in 70% proportions with Lippia alba, then in 50% proportions if the combination is made with Ocimum basilicum. Conclusion: This research has provided relevant results to guide players in the field of traditional medicine and users of herbal remedies.

Evolution of the biochemistry underpinning purine alkaloid metabolism in plants.

Purine alkaloids are naturally occurring nitrogenous methylated derivatives of purine nucleotide degradation products, having essential roles in medicine, food and various other aspects of our daily lives. They are generated through convergent evolution in different plant species. The pivotal reaction steps within the purine alkaloid metabolic pathways have been largely elucidated, and the convergent evolution of purine alkaloids has been substantiated through bioinformatic, biochemical and other research perspectives within S-adenosyl-ʟ-methionine-dependent N-methyltransferases. Currently, the biological and ecological roles of purine alkaloids, further refinement of the purine alkaloid metabolic pathways and the investigation of purine alkaloid adaptive evolutionary mechanisms continue to attract widespread research interest. The exploration of the purine alkaloid metabolic pathways also enhances our comprehension of the biochemical mechanism, providing insights into inter-species interactions and adaptive evolution and offering potential value in drug development and agricultural applications. Here, we review the progress of research in the distribution, metabolic pathway elucidation and regulation, evolutionary mechanism and ecological roles of purine alkaloids in plants. The opportunities and challenges involved in elucidating the biochemical basis and evolutionary mechanisms of the purine alkaloid metabolic pathways, as well as other research aspects, are also discussed. This article is part of the theme issue 'The evolution of plant meta-bolism'.

Preparation, Identification And Biological Activity Of Some Metals Complexes With A New Ligand (4-Nitro-N-((6-Oxo-6,9-Dihydro-1H-Purin-2-Yl)Carbamothioyl)Benzamid)

This study aimed to synthesize and characterize a novel guanine derivative, namely ( 4-nitro-N-((6-oxo-6,9-dihydro-1H-purin-2-yl)carbamothioyl)benzamid) (abbreviated as NPBL4). This compound possesses an intriguing chemical structure, consisting of a guanine moiety (a bicyclic heterocyclic base) linked to a benzamide group through a carbamothioyl linker. The synthesis of this nitrogenous base derivative involved two steps. Firstly 4-nitro-N-thioformylbenzamide was synthesized by reacting 4-nitrobenzoyl chloride with ammonium thiocyanate in acetone. Subsequently, the obtained 4-nitro-N-thioformylbenzamide was reacted with guanine to yield the desired ligand. In addition to the ligand synthesis, the study focused on preparing complexes of various metal ions (Mn+2, Co+2, Ni+2, Cu+2, Zn+2, Cd+2, and Pd+2) with the prepared guanine derivative. The ligand and complexes were subjected to comprehensive characterization using techniques such as infrared spectra, ultraviolet-visible spectra, 1H-NMR, 13C-NMR spectra, elemental analysis (C.H.N.S.), molar conductivity measurement, magnetic susceptibility, atomic absorption, melting point determination, and study the biological activity for the complexes. The results of these characterization studies led to the determination of the general formulas for the prepared complexes, which were found to be [MCl2(NPB)2], where M represents the respective metal ion (Mn+2, Co+2, Ni+2, Cu+2, Zn+2, Cd+2, and Pd+2). Notably, the geometric shape of all the prepared complexes was determined to be an octahedron. In summary, this study successfully synthesized and characterized a novel guanine derivative (NPB) and investigated its complexes with various metal ions. The findings provided valuable insights into the chemical properties and structural features of these compounds.

Sequestration of Dyes from Water into Poly(α-Olefins) Using Polyisobutylene Sequestering Agents

Trace concentrations of dyes are often present in textile wastewater streams and present a serious environmental problem. Thus, these dyes must be removed from wastewater either by degradation or sequestration prior to discharge of the wastewater into the environment. Existing processes to remove these wastewater contaminants include the use of solid sorbents to sequester dyes or the use of biochemical or chemical methods of dye degradation. However, these processes typically generate their own waste products, are not necessarily rapid because of the low dye concentration, and often use expensive or non-recyclable sequestrants or reagents. This paper describes a simple, recyclable, liquid–liquid extraction scheme where ionic dyes can be sequestered into poly(α-olefin) (PAO) solvent systems. The partitioning of anionic and cationic dyes from water into PAOs is facilitated by ionic PAO-phase anchored sequestering agents that are readily prepared from commercially available vinyl-terminated polyisobutylene (PIB). This is accomplished by a sequence of reactions involving hydroboration/oxidation, conversion of an alcohol into an iodide, and conversion of the resulting primary alkyl iodide into a cationic nitrogen derivative. The products of this synthetic sequence are cationic nitrogen iodide salts which serve as anionic sequestrants that are soluble in PAO. These studies showed that the resulting series of cationic PIB-bound cationic sequestering agents facilitated efficient extraction of anionic, azo, phthalein, and sulfonephthalein dyes from water into a hydrocarbon PAO phase. Since the hydrocarbon PAO phase is completely immiscible with water and the PIB derivatives are also insoluble in water, neither the sequestration solvent nor the sequestrants contaminate wastewater. The effectiveness and efficiency of these sequestrations were assayed by UV–visible spectroscopy. These spectroscopic studies showed that extraction efficiencies were in most cases >99%. These studies also involved procedures that allowed for the regeneration and recycling of these PAO sequestration systems. This allowed us to recycle the PAO solvent system for at least 10 sequential batch extractions where we sequestered sodium salts of methyl red and 4′,5′-dichlorofluorescein dyes from water with extraction efficiencies of >99%. These studies also showed that a PIB-bound derivative of the sodium salt of 1,1,1-trifluoromethylpentane-2,4-dione could be prepared from a PIB-bound carboxylic acid ester by a Claisen-like reaction and that the sodium salt of this β-diketone could be used to sequester cationic dyes from water. This PIB-bound anion rapidly and efficiently extracted >99% of methylene blue, malachite green, and safranine O from water based on UV–visible and 1H NMR spectroscopic assays.

The impact of the nitrogen atom on the optoelectronic, nonlinear optical, and thermodynamic properties of graphene quantum dots derived from dibenzocoronene: A DFT investigation

Because of their potential applications in electricity and photonics, graphene quantum dots (GQDs) with intriguing physical characteristics have attracted a lot of attention. Here we use density functional theory (DFT) with the B3LYP functional associated with the 6–31++G(d,p) basis to explore the effect of the nitrogen atom on the optoelectronic, nonlinear optical, and thermodynamic properties of dibenzocoronene (DBC) isomers. The pristine molecules of the DBC isomers have HOMO-LUMO energy gaps of 3.39 eV (DBCa), 3.39 eV (DBCb) and 3.65 eV (DBCc). Inserting a nitrogen atom into the DBC molecular structure considerably reduces the energy gap between these two orbitals. The materials thus obtained after nitrogen doping are DBCa-N, DBCb-N, and DBCc-N and have respective gap energies of 2.05, 1.80, and 1.65 eV (in other words, less than 3 eV). It can therefore be deduced that the compounds studied will be used as semiconductors in electronics. The static polarizabilities α of the N-doped DBC isomers obtained are 442.960, 443.523, and 455.657 au, respectively, each of these values being 4 times higher than that of the organic reference molecule for non-linear optical properties (para-nitroaniline pNA α = 114.7 au), while the first-order hyperpolarizabilities β obtained are 2689.838, 5572.137, and 12717.472 au, respectively. These values are approximately 2.5, 5, and 12 times higher than those of para-nitroaniline (β = 1072.44 au). Our results confirm that the investigated DBC nitrogen derivatives are good non-linear optical materials for photonics, data storage, dynamic imaging, optical signal processing, and computer systems. All the calculated thermodynamic properties show that the proposed molecules can be easily produced. This manuscript thus stands out as a good compass in the rational design of organic semiconductors for efficient electronic devices.

Recent Developments in the Antimicrobial Potential of Some Nitrogenous Heterocycles and their SAR Studies: A Review.

Infection remains a significant global health concern, with millions of new cases and deaths occurring due to infectious diseases. Currently, chemoprophylaxis and chemotherapy are the primary treatments, but side effects and toxicities pose challenges. Pathogenic microorganisms have developed resistance to antimicrobial medications. Nitrogen containing heterocyclic scaffolds possess the potential in drug discovery and are explored in various fields like pharmaceuticals, cosmetics, and agrochemicals. To minimize antimicrobial drug resistance, there is a need to design potent, safer antimicrobial lead compounds with higher selectivity and minimal cytotoxicity. The present review aims to outline several recent developments in medicinal chemistry aspect of nitrogenous heterocyclic derivatives with the following purposes: (1) To cast light on the recent literature reports of the last eight years ranging from 2015 to 2023 describing anti-microbial potential of nitrogen-containing heterocyclic derivatives which includes pyrazole, pyrazoline, imidazole, tetrazole and quinoline; (2) To brief the recent developments in the medicinal chemistry of nitrogenous heterocyclic derivatives that is directed towards their anti-microbial profile; (3) To summarize the complete correlation of structural features of nitrogenous heterocyclic molecules with the pharmacological action including in silico as well as mechanistic studies to provide thoughts accompanying the generation of lead molecules. Antimicrobial potential of nitrogenous heterocyclic molecules has been displayed by relating the structural features of various lead candidates with their in vitro as well as in vivo antimicrobial outcomes. In contrast, in silico computational analysis from different articles also helped to predict the SAR of potent molecules. Nitrogen containing heterocycles are involved in a range of natural to synthetic analogues with keen antimicrobial potency. It is an emerging need to generate new nitrogenous heterocyclic molecules in order to tackle the drug resistance in micro-organisms with more targeted selectivity as well as specificity. To limit the side effects associated with them and to combat the microbes acquired resistance towards the current drug regimen, novel nitrogenous heterocycle based antimicrobial agents are essential to be developed. This review connects the structural units present in lead compounds with their promising antimicrobial action.

Hypersonic boost-glide systems: Flight mechanics and plasma parameters evaluation through aero-thermo-chemical computational fluid dynamics

Currently, the conception, design, and development of hypersonic space-borne systems is a central topic of discussion among researchers and industrial stakeholders. In the design phase of a hypersonic manoeuvrable vehicle, it is essential to characterise the thermal heating and manage the problem of the communication blackout, in addition to other challenges concerning guidance, navigation and control, and propulsion. The interference of electromagnetic waves propagating in plasma affects the datalink and the radar detection of hypersonic targets. This work aims to provide valuable information about the aero-thermo-chemical behaviour of the fluid in the region around a hypersonic glider. Launch and re-entry phases of boost-glide systems have been modelled to perform trajectory predictions and assess range and flight paths under the effect of different manoeuvres, defining their possible performances. The resulting flight conditions are used to study the flow field surrounding a glider geometry similar to the Hypersonic Technology Vehicle-2. The thermodynamic and chemical fields around the body have been determined, and plasma parameters for novel electromagnetic interaction studies have been evaluated. Computational fluid dynamics simulations have been carried out to solve the averaged Navier-Stokes equations with the k−ω model for turbulent flows, coupled with the energy equation. Chemical non-equilibrium phenomena involving electronic energy relaxation as well as ionisation reactions have also been included. A gas mixture potentially composed of 11 species has been considered, namely oxygen and nitrogen derivatives. The electron number density is computed to evaluate the electron plasma and collision frequencies, essential parameters to characterise the electromagnetic interference caused by the plasma sheath. Among other results, high temperatures are reached at the nose region of the body in specific conditions of velocity and altitude, and non-negligible dissociation or ionisation of chemical species occurs. Plasma frequencies up to tens of GHz are reached in a region close to the body surface, while lower interference characterises the extended ionised wake.

Screening Metabolic Biomarkers in KRAS Mutated Mouse Acinar and Human Pancreatic Cancer Cells via Single-Cell Mass Spectrometry.

Pancreatic cancer is a highly aggressive and rapidly progressing disease, often diagnosed in advanced stages due to the absence of early noticeable symptoms. The KRAS mutation is a hallmark of pancreatic cancer, yet the underlying mechanisms driving pancreatic carcinogenesis remain elusive. Cancer cells display significant metabolic heterogeneity, which is relevant to the pathogenesis of cancer. Population measurements may obscure information about the metabolic heterogeneity among cancer cells. Therefore, it is crucial to analyze metabolites at the single-cell level to gain a more comprehensive understanding of metabolic heterogeneity. In this study, we employed a 3D-printed ionization source for metabolite analysis in both mice and human pancreatic cancer cells at the single-cell level. Using advanced machine learning algorithms and mass spectral feature selection, we successfully identified 23 distinct metabolites that are statistically significantly different in KRAS mutant human pancreatic cancer cells and mouse acinar cells bearing the oncogenic KRAS mutation. These metabolites encompass a variety of chemical classes, including organic nitrogen compounds, organic acids and derivatives, organoheterocyclic compounds, benzenoids, and lipids. These findings shed light on the metabolic remodeling associated with KRAS-driven pancreatic cancer initiation and indicate that the identified metabolites hold promise as potential diagnostic markers for early detection in pancreatic cancer patients.

Molecular insight into thymoquinone mechanism of action against Mycobacterium tuberculosis.

Natural products are promising antimicrobials, usually having multiple and different cellular targets than synthetic antibiotics. Their influence on bacteria at various metabolic and functional levels contributes to higher efficacy even against drug-resistant strains. One such compound is a naturally occurring p-benzoquinone - thymoquinone. It is effective against different bacteria, including multidrug-resistant and extremely drug-resistant Mycobacterium tuberculosis. Its antibacterial mechanism of action was studied in several bacterial species except mycobacteria. To get an insight into the antimycobacterial activity of thymoquinone at the molecular level, we performed metabolomic and transcriptomic analyzes of bacteria exposed to this compound. The expression of genes coding stress-responsive sigma factors revealed that thymoquinone rapidly induces the production of sigE transcripts. At the same time, prolonged influence results in the overexpression of all sigma factor genes and significantly upregulates sigF. The metabolomic analysis confirmed that the antimycobacterial activity of thymoquinone was related to the depletion of NAD and ATP pools and the downregulation of plasma membrane lipids. This state was observed after 24 h and was persistent the next day, suggesting that bacteria could not activate catabolic mechanisms and produce energy. Additionally, the presence of a thymoquinone nitrogen derivative in the bacterial broth and the culture was reported.

Synthesis, in vitro antioxidant, anticancer activity and molecular docking of new thiazole derivatives

Nitrogen and sulfur-containing heterocyclic aromatic derivatives play an enormous and important role in the field of medicine and in synthesis of pharmaceutically active compounds. In this study, a series of new 2-[1-(1,3-diphenyl-1H-pyrazol-4-yl)ethylidene]hydrazinyl)-4-methyl-5-aryldiazinyl)-thiazole derivatives (9a–d) was synthesized by an efficient and convenient method by reacting hydrazonoyl chloride derivatives (4) with carbothioamide derivative (3). The structures of these compounds were elucidated using elemental analyses, spectroscopic analyses (IR, NMR, Mass spectrometer) and computational measurements. Density functional theory (DFT) is performed to get the optimized structures with minimization Energy. The main goal of preparing these compounds is to evaluate their in vitro antioxidant and anticancer activities after studying their molecular docking. The docking was performed on compounds (9a–d) against tyrosine kinase (PDB ID: 2HCK). The results revealed that all docked compounds (9a-d) have a higher binding energy, ranging from −7.56 to −8,89 kcal/mol. compared to the original ligand quercetin, which was −5.92 kcal/mol. Moreover, the results of antioxidant and anticancer activity assay methods demonstrated that the tested derivatives (9a-d) exhibited potent antioxidant and anti-tumor activities against HepG2 cell lines.

In vitro biological studies and computational prediction-based analyses of pyrazolo[1,5-a]pyrimidine derivatives.

There is a need for new pharmaceutical discoveries from bioactive nitrogenous derivatives due to the emergence of scourges, numerous pandemics, and diverse health problems. In this context, pyrazolo[1,5-a]pyrimidine derivatives 12a and 12b were synthesized and screened to evaluate their biological potentials in vitro as antioxidants, anti-diabetics, anti-Alzheimer's, anti-arthritics, and anti-cancer agents. Additionally, the computational pharmacokinetic and toxicity properties of the two pyrazolo[1,5-a]pyrimidines 12a and 12b were calculated and analyzed. The preliminary studies and results of this work represent the initial steps toward more advanced studies and define the bioactive chemical structure of pyrazolo[1,5-a]pyrimidine derivatives with the goal of exploring new drugs to address numerous health problems.

Oxide Glasses for Removal of Ammonia and Nitrogen Derivatives from Industrial Wastewater

Adsorption is a rapid and known method to treat wastewater and remove contaminants such as ammonia (NH3+) and nitrogen derivatives. Herein, novel adsorption materials are demonstrated to eliminate the most hazard industrial and municipal contaminants including ammonia and nitrogen derivatives. Oxide glasses as new adsorbing media are beneficial for wastewater treatment due to dangling bond defects and non-bridging oxygen, which act as adsorption centers. Oxide glasses are characterized by their low cost and simple preparation method. Different types of oxide glasses including borate, phosphate, silicate, and germinate glasses are used as adsorbents to estimate the glass type of the optimal removal efficiency. It is found that the higher removal efficiency is exhibited for both borate and silicate glasses. Therefore, by preparing hybrid borate-silicate (borosilicate) glass, the best efficiency is achieved. The influences of boundary conditions including contact time, adsorption temperature, and adsorbent dosage on the efficiency of adsorption process are demonstrated. The optimal removal efficiency is achieved when using borosilicate glass sample (as adsorbent) with contact time of 90 min, adsorption temperature of 70 °C, and adsorbent dosage of 1.5 mg/100 ml. Finally, by comparing our results with the previous adsorption treatment works, it is found that adsorption capacity of ammonia reached to 9.12 mg/g, which is a valid and acceptable value.

Woman’s microbiome and obstetrical and perinatal risks: what do they have in common?

The article is devoted to the review of modern scientific publications about the microbiome of a woman and its importance in obstetric and perinatal practice. The composition of the microbiome is changed both in the process of human evolution and personally and in different periods of a person’s life. However, on the other hand, the microbiome is influenced by the specific environment in which a person lives. It consists of a certain collection of genomes of all microorganisms. Complications during pregnancy occur frequently, according to statistics – in every sixth pregnant woman, and pose a danger to the health of the mother and child.During pregnancy, the richness and diversity of the vaginal microbiome decreases, and different species of Lactobacillus play a dominant role. The microbiome stability is hypothesized to be associated with higher levels of estrogen concentration, absence of menstruation, and modification of cervical and vaginal fluids. During an uncomplicated pregnancy, the taxonomic composition of the vaginal microbiota remains stable with the exception of the period before labor, when there is an increase in microbial diversity. This makes the vaginal microbiome similar to that of a non-pregnant woman and is believed to be a trigger for the labor process to begin.The recent studies have determined a relationship between changes in the microbiome during pregnancy and the occurrence of complications in these women. Any change or disturbance in the microbiome balance can be involved in inflammatory processes, which can potentially have adverse effects on the course of pregnancy. A major interaction between the oral microbiome and preeclampsia involves the production of nitrogen derivatives, especially nitric oxide (NO). NO is produced from L-arginine via NO synthases (NOS), and is involved in vascular processes, especially vasodilation and tissue protection. Also, NO is indirectly involved in the processes that occur in the presence of chronic cardiovascular diseases, including hypertension and preeclampsia.In recent years, scientists have begun actively to study a correlation between changes in the gut microbiome and various nosologies regarding gestational diabetes. There is not much of this data at the moment. The gut microbiome is known to modulate insulin resistance and the inflammatory response, and changes in the microbiome may be associated with metabolic diseases. It is hypothesized that changes in the gut microbiome may lead to metabolic diseases through several mechanisms: abnormal intestinal permeability, increased absorption of lipopolysaccharide, abnormal production of short-chain fatty acids, altered conversion of primary bile acids, and enhanced production of bacterial toxins (e.g., trimethylamine-N-oxide).During full-term pregnancy, the “dynamic stability” of the vaginal microbiome is described as a higher concentration of Lactobacillus species starting at 20 weeks of gestation due to increased glycogen availability and a less complex and diverse microflora. This condition may be due to the lack of cyclical hormonal changes during pregnancy. Lactobacillus and small bacterial diversity are thought to be critical factors for the initiation of labor at the end of the pregnancy.Future therapeutic strategies are likely to be applied to modulate the composition of the microbiome, including the use of pro- and prebiotics and dietary modification. However, further research is needed to identify specific tools that can be used to develop personalized therapeutic approaches for individualized prevention and treatment.

Antiradical and Antioxidant Activity of Compounds Containing 1,3-Dicarbonyl Moiety: An Overview.

Free radicals and oxidants may cause various damages both to the lifeworld and different products. A typical solution for the prophylaxis of oxidation-caused conditions is the usage of various antioxidants. Among them, various classes are found-polyphenols, conjugated polyalkenes, and some sulfur and nitrogen derivatives. Regarding the active site in the molecules, a widely discussed group of compounds are 1,3-dicarbonyl compounds. Among them are natural (e.g., curcumin and pulvinic acids) and synthetic (e.g., 4-hydroxy coumarins, substituted Meldrum's acids) compounds. Herein, information about various compounds containing the 1,3-dicarbonyl moiety is covered, and their antiradical and antioxidant activity, depending on the structure, is discussed.

Circular Design and Functionalized Upcycling of Waste Commodity Polystyrene via C-H Activation Using Microwave-Assisted Multicomponent Synthesis.

The inefficient reuse and recycling of plastics-and the current surge of medical and take-out food packaging use during the pandemic-have exacerbated the environmental burden. This impels the development of alternative recycling/upcycling methods to pivot toward circularity. We report the use of the Mannich three-component coupling reaction for the modification of polystyrene (PS) recovered with a 99.1% yield from waste food containers to form functionalized nitrogen and oxygen-rich PS derivatives. A series of functionalized PS with increasing moles of formaldehyde (F) and morpholine (M) (0.5 × 10-2, 1.0 × 10-2, and 2.0 × 10-2 mol) was achieved using a sol-gel-derived Fe-TiO2 catalyst in a solvent-free, microwave-assisted synthesis. Modified polymers were characterized with viscometry, 1H NMR, 13CNMR (DEPT) FTIR, XPS, UV, and TGA. Functionalization scaled with an increasing ratio, validating the 3CR approach. Further functionalization was constrained by a competing oxidative degradation; however, the varying hydrogen bond density due to nitrogen and oxygen-rich species at higher ratios was shown to compensate for molecular weight loss. The integration of the N-cyclic quaternary ammonium cations exhibited the potential of functionalized polymers for ion-exchange membrane applications.

One-pot mediated synthesis of pyrimidine and quinazoline annulated derivatives of nitrogen containing five membered rings through their nitrile derivatives as antibacterial agents

ABSTRACT. Novel five-membered ring (pyrrole, pyrazole and imidazole)-based pyrimidine and quinazoline derivatives were synthesized by one-pot domino approach. This approach has the advantages of high yield, mild reaction conditions and a simple work-up procedure. The structure of the synthesized compound was elucidated by spectroscopy technique and elemental analysis. The synthesized compound were examined for antimicrobial activity against four bacteria (E. coli, S. pyogenes, S. aureus, and P. aeruginosa) and two fungi (C. albicans and A. clavatus) and most of the synthesized compound exhibited moderate to good activity against reference drug ampicillin, ciprofloxacin, norfloxacin, gentamycin, nystatin and griseofulvin, respectively.
 
 KEY WORDS: One-pot, Pyrrole, Pyrazole, Imidazole, Pyrimidine, Quinazoline, Antimicrobial activity
 
 Bull. Chem. Soc. Ethiop. 2023, 37(5), 1193-1208. 
 DOI: https://dx.doi.org/10.4314/bcse.v37i5.12

Effects of substituting sericea lespedeza for lucerne on nutrient digestibility and utilization in feedlot lambs

The current study evaluated the effects of dietary increments of sericea lespedeza (SL, Lespedeza juncea var. sericea) as a substitute for lucerne (Medicago sativa L.) in lamb finishing diets on nutrient intake and digestibility, rumen fermentation, microbial nitrogen (N) supply, N balance, and N utilization efficiency. Following a completely randomized design, 25 Dohne Merino intact male lambs (4–5 months old) with an average initial weight of 28.2 ± 1.74 kg were equally assigned to five dietary treatments containing 0, 62.5, 125, 187.5 and 250 g SL per kg diet as replacement for lucerne in total mixed rations. The lambs were acclimatized to the diets and environment for 21 days before data collection during a 5-day period. Daily, the feed offered, refusals and total fecal matter were weighed to determine nutrient intake and digestibility, while urine was collected for the determination of urine nitrogen and purine derivatives excretion. At the end of the data collection period, lambs were humanely slaughtered, and the rumen was opened to determine ruminal pH, and collect representative samples of rumen fluid to determine ruminal fermentation parameters. Dietary increments of SL had no influence (P > 0.05) on the lambs’ nutrient intake except for neutral detergent fiber (aNDFom) intake which increased linearly (P ≤ 0.05) with SL inclusion. As SL increased in the diets, the apparent total tract digestibility of dry matter, organic matter, crude protein, aNDFom, and ether extract linearly declined (P ≤ 0.05). The concentrations of butyrate, valerate, and iso-valerate were quadratically (P ≤ 0.05) influenced by dietary inclusion of SL with maximum concentrations observed at the 125 g SL/kg inclusion level. Dietary inclusion of SL had no influence (P > 0.05) on purine derivatives excretion, microbial N supply, N balance, and N utilization efficiency. Overall, replacing lucerne with SL up to 250 g/kg in lamb finishing diets had no detrimental effects on nutrient intake and utilization.

α-Amino acid-assisted autoxidation of naphthalene proton sponge affording 1,4-naphthoquinone nitrogen derivatives

1,8-Bis(dimethylamino)naphthalene (naphthalene proton sponge) equipped at position 4 with N-terminal α-amino acid residues undergoes unprecedented easy autoxidation in basic medium forming 5-dimethylamino-1,4-naphthoquinone along with minor amounts of its derivatives. The new reaction is of interest against the background of wide distribution of 1,4-naphthoquinones in nature, their high biological significance and extremely limited information on nitrogen compounds of this series.

Application of High-Performance Liquid Chromatography with Fluorescence Detection for Non-Polar Heterocyclic Aromatic Amines and Acridine Derivatives Determination in Pork Loin Roasted in a Roasting Bag.

Heat treatment of meat can lead to the formation of carcinogenic organic compounds. The influence of dried fruits on the formation of non-polar heterocyclic aromatic amines (carbolines) and nitrogen derivatives of polycyclic aromatic hydrocarbons (azaarenes) in roasted pork loin was elucidated. Two hundred grams of fruit per 1 kg of meat were used as stuffing. Carbolines, derivatives of pyridoimidazole and pyridoindole, and azaarenes (benzoacridines and dibenzoacridines) were determined by means of high-performance liquid chromatography with fluorescence detection. The total concentration of six δ-, γ- and α-carbolines in roasted pork loin was 1.3 ng/g. This content decreased by 64%, 58%, and 54% in pork loin stuffed with prunes, apricots, and cranberries, respectively. Concentrations of β-carbolines (harmane and norharmane) increased under the influence of added fruits. The norharmane content increased the most, from 2.2 ng/g in the control sample to 12.3 ng/g in meat prepared with cranberries. The harmane content increased from 1.0 ng/g to 3.6 ng/g in meat with prunes. The total concentration of azaarenes (two benzoacridines and dibenzo[a,c]acridine), which was close to 0.1 ng/g, decreased in dishes with prunes and apricots by 54% and 12%, respectively. Azaarenes were not found in samples of meat stuffed with cranberries.