Oxygen-containing Compounds Research Articles

Brønsted-acidic ionic liquid supported nanomagnetic: a novel and reusable catalyst for synthesis of oxygen-containing heterocyclic compounds

Brønsted-acidic ionic liquid supported nanomagnetic: a novel and reusable catalyst for synthesis of oxygen-containing heterocyclic compounds

The Role of Undecenoic Acid on the Preparation of Decorated MCM-41/Polyethylene Hybrids by In Situ Polymerization: Catalytic Aspects and Properties of the Resultant Materials

Functionalized polyethylene-based nanocomposites were prepared by in situ polymerization of ethylene with modified or neat MCM-41 nanoparticles (NMCM-41). Two different synthetic approaches were investigated to improve the compatibility between the hydrophobic HDPE matrix and the hydrophilic NMCM-41: (i) incorporation of UA into the polymeric matrix by copolymerization with ethylene, promoted by the zirconocene catalyst under homogeneous conditions, in the presence of pristine NMCM-41; (ii) use of undecenoic acid (UA) as an interfacial agent to obtain decorated NMCM-41 to be used as nanofiller for the in situ ethylene polymerization, catalyzed by Cp2ZrCl2/MAO under supported conditions. The strong polar character of the carboxylic group is expected to either increase the hydrophilicity of the HDPE chains (strategy i) or interact with the NMCM-41 surface and provide an additional link to the polymeric chains via copolymerization of the vinyl group under supported conditions (strategy ii). Although metallocene catalysts have been shown to copolymerize olefins with functional monomers, the presence of oxygen-containing compounds in the reaction media strongly affects the polymerization activity as a result of the interaction of functional groups with the electrophilic active center of the catalyst. Thus, UA was pre-contacted with tri(isobutyl)aluminum (TIBA) prior to its use in the polymerization to reduce the deactivating character of the carboxylic acid groups towards the zirconocene catalyst. The influence of the UA presence on the polymerization behavior of the protection step is discussed, and the polymerization activities observed for the different approaches are compared. In addition, the thermal behavior and structural details of the resulting materials have been characterized. The impact of using neat or functionalized NMCM-41 on the final dispersion within the polymeric matrix is also analyzed, which is correlated with the mechanical performance exhibited by these HDPE_UA_NMCM-41 nanocomposites.

Effect of Solvent Pretreatment on the Flash Pyrolysis Performance of Yinggema Lignite

Yinggema lignite (YL) was pretreated with isometric acetone/carbon disulfide mixed solvent to obtain the residue (RYL) and, then, RYL was separated by density difference with carbon tetrachloride to obtain the light residue (LRYL). The flash pyrolysis performances of YL and LRYL were analyzed by thermogravimetry–Fourier transform infrared spectrometer–Gas chromatography/mass spectrometer (TG-FTIR-GC/MS). The results showed that solvent pretreatment could remove some small molecules in the coal and swell the used coal, leading to the increase in pyrolysis reactivity. The intensity and absorption peak area of C=O from LRYL were significantly reduced compared to YL, resulting from the high hydrogen-donating ability of acetone. The main gaseous products of both samples are H2O, CH4, CO2, and CO; the hydrocarbons detected by GC/MS in the pyrolysis products of YL and LRYL at 450 °C were mainly alkanes, alkenes, and arenes, with the higher relative contents of alkanes of 31.1% and 36.2%, followed by arenes of 27.1% and 22.6%, respectively. The oxygen-containing compounds were mainly alcohols and phenols. It is speculated that the pretreated coal could expose more oxygen-containing functional groups, facilitating their conversion to phenolic hydroxyl groups during the pyrolysis process, resulting in more phenolic compounds.

Investigation on the catalytic performance of magnetic copper ferrite nanoparticles in the catalytic hydroconversion of Hanglaiwan long flame coal

Magnetic copper ferrite (CuFe2O4) was prepared by hydrothermal synthesis method and used for the catalytic hydroconversion (CHC) of Hanglaiwan long flame coal (HLFC) in cyclohexane under 1 MPa of initial hydrogen pressure (IHP) at 300 °C for 4 h. The total yield of soluble portion (SP) from the CHC is 33.7 wt%, significantly being higher than that (10.5 wt%) from the non-CHC (NCHC) under the same conditions. The main compounds detected in SPCHC (for CHC) are arenes and oxygen-containing organic compounds (OCOCs). Benzyloxybenzene (BOB), 2-(benzyloxy)naphthalene (BON), oxybis(methylene)dibenzene (OBMDB), oxydibenzene (ODB), and 2,2′-oxydinaphthalene (ODN) were used as HLFC-related model compounds to investigate the catalytic activity of CuFe2O4 and understand the CHC mechanism of HLFC. According to the model reactions, CuFe2O4 activates H2 to biatomic active hydrogen (H…H) and splits H…H to mobile H+ and immobile H-. H+ addition to oxygen atoms (OAs) in >C-O- bridged bonds (BBs) cleaves the BBs and releases SP during the CHC of HLFC.

Pyrolysis of Mixed Date Stones and Pistachio Shells: Identification of Bio-Oil and Utilization of Bio-Char as Activated Carbon Precursor.

Thermal pyrolysis of mixed date stones and pistachio shells in a semi-batch reactor was addressed in this study. The highest yield of liquids (51.20 %) was produced at 500 °C, 90 min, 20 °C/min heating rate, and 50 mesh particle size. Under these conditions, yield of liquid from date stones and pistachio shells separately was 49.12 % and 47.67 %, respectively. The FT-IR results confirmed the presence of multiple oxygen-containing compounds in the bio-oil. Results from GC-MS declared that it was predominately composed of acids (57.57 %), esters (21.35 %), phenols (4.63 5), and alcohols (3.49 5). The obtained biochar was transformed into activated carbon (AC) by the optimized ZnCl2 activation method. The ideal AC was synthesized at 600 °C for 60 min using a 2 : 1 ZnCl2 : biochar impregnation ratio. FESEM and XRD measurements showed that the AC was amorphous. The prepared AC was effective in eliminating dibenzothiophene (DBT) from model fuel (200 ppm DBT/hexane) with a maximum performance 95.26 % at 40 °C for 1h using 0.35 g of the AC. The exhausted AC was regenerated and reutilized 4 times, and removal efficiency reached 88.23 % in the 4th cycle under ideal working conditions.

A new strategy to study geochemical characteristics and migration of crude oils in Zhu I Depression, Pearl River Mouth Basin, South China Sea

Oxygen- and sulfur-containing compounds were proved to be good alternatives to pyrrolic nitrogen compounds in the study of oil migration. To promote the detectability of complex and trace analytes, a simple and efficient device, gas purge microsyringe extraction (GP-MSE), was developed and combined with comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GC × GC-TOFMS) for the simultaneous analysis of target compounds. Oil samples were collected from the Zhu I Depression of the Pearl River Mouth Basin in the South China Sea and classified into three groups in terms of geochemical distribution characteristics, parameters and concentrations of carbon isotopes, alkanes, diamondoids, terpanes and steranes. Based on nitrogen-, sulfur- and oxygen-containing compounds, the general oil filling into the Zhu Ⅰ Depression was determined from the central sags southward to the Dongsha Uplift. Faults provide pathways for vertical migration and delta sandstones served as the main lateral and long-distance regional migration pathways. The molecular dynamics (MD) simulation provides a nanoscale perspective into geochromatographic fractionation, which is generated mainly by the interaction between polar compounds and clay minerals. In MD simulations, the binding affinity of carbazole, dibenzothiophene and dibenzofuran on clay minerals is higher than that on non-clay minerals due to the available active sites on the surface of clay minerals for the formation of electrostatic and van der Waals interaction. Carbazole, dibenzothiophene and dibenzofuran achieve adsorption stability in a parallel manner on chlorite and kaolinite, whereas on illite, adsorption stability is achieved in tilted manner. Based on the adsorption energies, kaolinite shows the highest adsorption affinity, whereas calcite exhibits the lowest adsorption affinity. Microcline even demonstrates a noticeable repulsive effect. The geochromatographic fractionation effect seems to be not controlled only by the affinity between oil composition and clay mineral during oil migration.

A feasible approach for the treatment of waste computer casing plastic using subcritical to supercritical acetone: Statistical modelling and optimization

Electronic waste (e-waste) usage has increased tremendously with the rapid evolution of technologies. The accumulated e-waste has now emerged as one of the crucial concerns regarding environmental pollution and human health. Recycling e-waste is commonly focused on metal recovery; nevertheless, a significant fraction of plastics (20–30%) are in e-waste. There is an indispensable need to focus on e-waste plastic recycling in an effective way, which has been mostly overlooked to date. An environmentally safe and efficient study is conducted using subcritical to supercritical acetone (SCA) to degrade the real waste computer casing plastics (WCCP) in the central composite design (CCD) of response surface methodology (RSM) to achieve the maximum oil yield of the product. The experiment parameters were varied in the temperature span of 150–300 °C, residence time between 30 and 120 min, solid/liquid ratio between 0.02 and 0.05 (g/ml), and NaOH amount from 0 to 0.5 g. Adding NaOH into the acetone helps to achieve efficient degradation and debromination efficiency. The study emphasized the attributes of oils and solid products recovered from the SCA-treated WCCP. The characterization of feed and formed products is performed with different characterization techniques such as TGA, CHNS, ICP-MS, FTIR, GC-MS, Bomb calorimeter, XRF, and FESEM. The highest oil yield achieved is 87.89% from the SCA process at 300 °C, in 120min, 0.05 S/L ratio, and 0.5 g of NaOH. GC-MS results disclose that the liquid product (oil) comprises single- and duplicate-ringed aromatic and oxygen-containing compounds. Isophorone is the significant component of the liquid product obtained. Furthermore, SCA's possible polymer degradation mechanistic route, bromine distribution, economic feasibility, and environmental aspect were also explored. This present work represents an environmentally friendly and promising approach for recycling the plastic fraction of e-waste and recovering valuable chemicals from WCCP.

Properties and Analysis of Liquid Alternative Fuels III: Vegetable Oils and Hydrotreated Vegetable Oils

The importance of alternative fuels and biofuels is constantly growing due to energy security, sustainability, and social responsibility. This article is another in a series of review articles designed to recapitulate information on the required properties of individual alternative fuels, their testing methods, and the significance of individual analyses. This article is focused on fuels based on vegetable oils and hydrotreated vegetable oils. Rapeseed oil is a triglyceride-based fuel that can be burned in modified diesel engines. Modification of the engine consists in the inclusion of preheating of the fuel or modification of the injection system, due to the high viscosity of this fuel. Rapeseed oil and vegetable oils in general have a higher oxygen content than conventional diesel fuels, which is associated with a lower energy content than that of diesel fuels. Compared to diesel, vegetable oils have a higher density, a lower cetane number, and a significantly higher flash point and viscosity. Vegetable oils also have low oxidative stability. Physical properties monitored in rapeseed oils include density, viscosity, flash point, and calorific value. From the chemical properties, the iodine number, acidity number, water content, calcium, magnesium, sulfur, and phosphorus are monitored. From the other properties, oxidative stability, ignitability, ash content, carbonation residue, content of impurities, and appearance are monitored for rapeseed oils. HVO is a high-quality fuel for standard diesel engines. Due to the hydrocarbon character of HVO, no engine modification is required. HVO has a very high cetane number, very good low-temperature properties, optimal viscosity, high flash point, excellent oxidative stability, and a very low content of undesirable contaminants such as aromatic hydrocarbons, sulfur, nitrogen, and oxygen-containing compounds. Compared to diesel fuels, HVO has a lower density. The observed qualitative parameters and testing methods are very similar to those of conventional diesel fuel B7. The main difference lies in the modified determination of aromatic hydrocarbons.

Экологические особенности и биотехнологические возможности почвенных актинобактерий (обзор)

Actinobacteria are gram-positive aerobic and facultative anaerobic bacteria that tend to form branching hyphae capable of developing into mycelium. Their main role is in the decomposition of complex polymers in the soil: lignin, cellulose, chitin, humus substances; fertility formation; production of antibiotic substances; accumulation of biologically active compounds. Actinobacteria secrete into the environment a complex of secondary exometabolites of various compositions with aliphatic, carbocyclic, heterocyclic, nitrogenous, oxygen-containing and sulfur-containing compounds. Most of the isolated secondary metabolites have antibiotic, antimicrobial, antiviral, herbicidal, insecticidal properties. Biotechnological capabilities of soil actinobacteria producing biologically active substances with a wide range of environmental effects are used in the development of multifunctional biologics for various industries. Actinobacteria play a crucial role in optimizing the growing conditions of plants, and therefore there is a natural interest in studying the factors that influence the relationship between actinobacteria and various crops in specific soil conditions. The development of this issue is an important link in the ecological characterization of the soil microbial complex and it will help to develop the theoretical foundations for the targeted regulation of the interactions of actinobacteria with phytopathogenic microorganisms and insect pests. The purpose of this work is to analyze the ecological features and biotechnological capabilities of soil actinobacteria. The review describes the distribution of actinobacteria in various types of soils, including those with the presence of pollutant; the composition of the metabolites produced; relationships with other microorganisms, as well as biotechnological properties and the possibility of using actinobacteria for the development of biological products for agroecosystems.

P-800 Autologous stem cell ovarian transplant induced long-lasting effects on the plasma proteome of women with premature ovarian insufficiency

Abstract Study question Does autologous stem cell ovarian transplant (ASCOT) induce any long-term modifications in the plasma proteomic profile of women with premature ovarian insufficiency (POI)? Summary answer Stem cell mobilization and infusion into the ovary elicit long-term proteomic changes in peripheral blood plasma composition in women with POI, reverting age-related proteomic changes. What is known already Patients with POI are challenging to treat, with oocyte donation remaining as the only feasible option to achieve pregnancy. Previous attempts to overcome the fertility problems of these patients have mainly been based on ovarian stimulation, and were likely unsuccessful due to the lack of stimulable antral follicles remaining in the ovaries. Our group described that ASCOT in patients with impaired ovarian function improves ovarian reserve biomarkers, follicle and oocyte quantity enabling pregnancy and delivery of healthy babies. Beneficial effects of ASCOT were associated with the presence of different stem-cell secreted factors in apheresis plasma. Study design, size, duration Experimental cohort study with plasma samples of POI women undergoing stem cell mobilization with granulocyte-colony stimulating factor (mobilization arm; N = 3) or stem cell mobilization and infusion into the ovarian artery (ASCOT arm; N = 3). Peripheral plasma samples were collected from all patients at recruitment (Pre), during bone marrow stem cell mobilization and collection by apheresis (Apheresis), and three months after mobilization or ASCOT (Post). Participants/materials, setting, methods Proteins were isolated from plasma samples and quantified by SWATHTM to compare the plasma proteomic profile of the different time points (Pre, Apheresis, Post), using an ElasticNet penalized linear regression method. To determine the biological processes affected by stem cell mobilization and infusion into the ovary, a Gene Ontology Enrichment Analysis for the differentially expressed proteins (DEPs) was performed, considering significantly enriched those GO Biological Processes with a False Discovery Rate <0.05. Main results and the role of chance Discriminant analysis highlighted clear distinctions between the plasma proteome at the three evaluated time points. Both the stem cell mobilization and ASCOT technique induced statistically significant modifications in the plasma composition, reversing some age-related protein expression changes. Specifically, differences between Apheresis and Pre samples were explained by fourteen DEPs, revealing the functional analysis an enrichment in processes related to the complement cascade, immune system, and platelet degranulation. When the link of these proteomic changes with aging was evaluated, we found three proteins that were upregulated in Apheresis [C1QC, LYSC, LYAM1] whose plasma levels decrease with aging, and one downregulated protein [CRP] whose expression rises with age. Regarding Post samples, twenty-four DEPs with respect to Pre condition were found within the mobilization arm, being two of them linked with aging [MMP2 and ALDOC]. These DEPs were related with immune response and platelet degranulation but also with processes associated with responses to oxygen-containing compounds and growth hormones, and blood vessel maturation. Within the ASCOT arm, Pre and Post samples were clearly differentiated by eleven DEPs, although any GO Biological Process were found. Nevertheless, among these DEPs, we found DIAC which increases in plasma with aging and was downregulated after ASCOT. Limitations, reasons for caution Considering the small sample size used in this study, further experimental studies will be needed to validate the results. Moreover, further research will be necessary to determine the extent of the regenerative effects of the identified DEPs within the ovaries, and their direct implications in ovarian aging. Wider implications of the findings Our findings highlight the potential proteins and biological processes that may promote the follicle activation and growth observed after ASCOT. Identifying plasma proteins that regenerate aged or damaged ovaries could lead to more effective, targeted and/or preventive therapies for affected patients. Funding: CIPROM/2021/058, PI21/00170, CP19/00141 and CD20/00116. Trial registration number NCT03535480

Boosting specific capacitance of Mo-Co-(S,O) electrode via a synergistic optimization strategy

Low electrical conductivity and insufficient active sites of Co-based binary metal oxides or sulfides hamper their practical specific capacitance especially at high current densities. In the current work, we provide a novel synergistic optimization strategy including P doping and constant-current-charge activation (CA) to greatly improve the specific capacitance of sulfur and oxygen-containing Mo-Co binary compounds (Mo-Co-(S,O)) electrode. The synergistic effect of the P doping and activation not only increases the electrical conductivity but also improves the electroactive sites. As a result, the optimized Mo-Co-(S,O)/P-CA electrode shows exceptional specific capacitance (∼9.64 F cm−2/2931 F g−1 at 12.5 mA cm−2), approximately 20 times the pristine Mo-Co-(S,O). Moreover, an asymmetric supercapacitor prepared with Mo-Co-(S,O)/P-CA cathode and conductive carbon cloth achieves a high energy density of 0.61 mWh cm−2 at a power density of 4.25 mW cm−2, and outstanding cyclic performance with 121.6% of capacitance retention after 12,000 cycles.

Pyrolysis of different types of waste cooking oil in the presence/absence HZSM-5 catalyst: Influence of feedstock characteristics on aromatic formation

In this study, aromatics were prepared by continuous microwave pyrolysis experiment in the presence and absence of HZSM-5 using different types of waste cooking oil (corn oil, rice oil, rapeseed oil, sunflower seed oil, soybean oil, blending oil, peanut oil, palm oil), and the effects of raw material characteristics on pyrolysis products were compared. The results showed that the fatty acid composition of waste cooking oil affects the composition of pyrolysis products. For example, linoleic acid promotes naphthene and inhibits olefin formation; oleic acid is easy to form C9 and C10 compounds; compared with oleic acid and linoleic acid, palmitic acid is not conducive to deoxidation. In addition, the deoxidation degree of waste cooking oil is related to the raw material H/Ceff, and the order from high to low is corn oil > rapeseed oil > sunflower seed oil > peanut oil > soybean oil. The yield of the oxygen-containing compounds is inversely proportional to it. With the use of HZSM-5 catalyst, the content of toluene and xylene in liquid products is significantly increases, especially the content of xylene. The catalytic effect of rice oil is the most significant, with xylene content increased by 19.2% compared with the non-catalytic pyrolysis. This provides a reference for the efficient treatment of waste oil and the production of aromatics in the future.

Estimating aging sensitivity of bitumen using FTIR spectroscopy and multivariate evaluation

In this work, a methodology based on Fourier transform infrared (FTIR) spectroscopy and multivariate evaluation is presented to estimate the aging sensitivity of bitumen based on the unaged samples and thus without the need for time- and material-consuming aging simulations. For this purpose, factor analysis and linear discriminant analysis are used to develop a statistical model based on the FTIR spectra of unaged bitumen samples, which can be used fast and simple in everyday laboratory work and allows to assign the bitumen to a low, moderate, or strong aging sensitivity. The evaluation of the aging sensitivity is based on the complex shear modulus |G*| and the phase angle δ from the measurement with a dynamic shear rheometer (DSR), whose aging-related changes were captured as the slope in the Black diagram. A relevant influence on the classification concerning the aging sensitivity has the oxygen-containing compounds (sulfoxide, hydroxyl and partly carbonyl compounds), whereby lower contents and thus less preaged bitumen tend to have a stronger aging sensitivity. However, in addition to the oxygen-containing compounds, the structure of the aliphatic and aromatic compounds and, in particular, the interaction of the different structures are decisive for the aging sensitivity.

Ultrasound-assisted Synthesis of Nitrogen and Oxygen Containing Heterocycles

Abstract: Ultrasound is well explored in the preparation of several heterocycles as it is an eco-friendly, safer and cheaper technique compared to the previous conventional synthetic approach. Ultrasonication offers a great deal of interest for chemists as it not only lowers the reaction time but also markedly reduces the use of hazardous chemicals and enhances the purity of synthesized compounds. Since the application of ultrasound waves acts as a nonpolluting energy source, therefore, it is an area of great importance in the field of green and sustainable chemistry. Also, nitrogen and oxygen-based pharmaceuticals have been found to be a beneficial tool for modifying solubility, lipophilicity, polarity and other important pharmacokinetic parameters which aid in optimizing ADMET characteristics of drug candidates. Further, nitrogen and oxygen-containing compounds have been reported to exhibit antibacterial, antiviral, anti-inflammatory, anticancer, analgesic, antihyperglycemic action etc. Therefore, the review focues to coveron covering the latest applications of ultrasonication in the preparation of oxygen and nitrogen nitrogencontaining heterocycles holding immense importance in therapeutically active molecules, which will aid new researchers in their ongoingnd future research.

Catalytic pyrolysis of microalgal lipids to liquid biofuels: Metal oxide doped catalysts with hierarchically porous structure and their performance

Catalytic pyrolysis of lipids is an alternative pathway for alternative aviation fuel production with advantages of H2-free and mild reaction conditions. However, it is still hindered by coking of catalysts and low selectivity of kerosene. In this research, composite catalysts were synthesized via postsynthesis method (alkali treatment) followed by doping of metal oxides (ZnO, La2O3, and CeO2). Catalytic performance of as-synthesized catalysts was evaluated during catalytic pyrolysis of microalgal lipids. The characterization of BET, XRD, SEM, NH3-TPD for catalysts indicated that alkaline treatment increased the mesoporous structure (5.28–5.91 nm) of microporous zeolite HZSM-5 to form a hierarchically porous structure without apparent disruption of crystal structure of zeolite, while doping of metal oxides (about 10 wt%) enhanced the performance of hetero-atoms (oxygen and nitrogen) removal. The acidity of as-synthesized catalysts significantly decreased from 1175.61 μmol/g (HZSM-5) to 406.77 μmol/g (Ce-MHZ). After catalytic pyrolysis carbon number distribution and compound type of produced liquid fuels tended to high kerosene components (above 40%) and increased hydrocarbon content with reduced content of oxygen-containing compounds. The hierarchically porous zeolite also presented aromatization for aromatic hydrocarbons in alternative aviation fuels. Catalytic mechanism was also elucidated including complex reactions of decarboxylation, decarbonylation, carbon chain cracking, and aromatization.

Investigation on the Composition and Extraction Mechanism of the Soluble Species from Oily Sludge by Solvent Extraction.

Oily sludge (OS) was extracted with petroleum ether (PE), methanol, carbon disulfide (CDS), acetone, and isometric CDS/acetone mixture (IMCDSAM), respectively, to obtain soluble species (E1-E5) and extraction residues (R1-R5). The soluble species were analyzed by gas chromatography/mass spectrometry (GC/MS), and the extraction residues were characterized by Fourier transform infrared spectrometry (FTIR) and thermogravimetric analysis (TGA). Results showed that the extract yield of the soluble species from OS using CDS and IMCDSAM as the solvent was 61.0 and 67.3%, respectively. GC/MS results exhibited that the compounds detected in E1-E5 are mainly hydrocarbons and oxygen-containing compounds. E1-E5 are rich in alkanes, alkenes, ketones, alcohols, and other oxygen-containing compounds. Double-bond equivalence (DBE) and carbon numbers (CNs) of the compounds detected in E1, E2, and E4 are distributed in 0-4 (DBE) and 10-20 (CNs), respectively, while the DBE and CNs of the detected compounds in E3 and E5 are concentrated in 0-6 and 15-35, respectively. Thermogravimetry-differential thermogravimetry (TG-DTG) profiles presented that pyrolysis of OS occurred mainly in the temperature range of 150-750 °C, while pyrolysis of R1-R5 took place in the range of 350-750 °C. In the temperature range of 150-550 °C, the weight losses of OS and each extraction residue differ significantly, with OS having a much higher weight loss than the extraction residues. Meanwhile, the possible mechanism of oily sludge extraction was considered. Results revealed that selecting a low-polar or nonpolar solvent capable of selectively destroying hydrogen bonds and/or aromatic interactions is critical for improving the extract yield of OS.

Design, synthesis, and cytotoxic activity of some novel N-(substituted) benzamide derivatives bearing coumarin and 1-azocoumarin compounds

ABSTRACT. Among oxygen-containing heterocyclic compounds such as coumarin and azacoumarin derivatives, the scaffold has become an important construction motif for developing new drugs. Coumarin and its derivatives possess many types of biological activities and have been reported to show significant cytotoxic activity. N-(6,8-disubstituted coumarin-3-yl)benzamides (8a-c) namely (3-N-(benzoyl) aminocoumarin-6-ylmethyl acetate (8a); N-[6-(1-acetylpyrazol-3-yldiazineyl) coumarin-3-yl] benzamide (8b); N-(8-methoxy-6-bromo-coumarin-3-yl) benzamide (8c), were synthesized via a cyclocondensation reaction of 5-(chloromethyl)-2-hydroxybenzaldehyde (3), 5-(pyrazol-3-yl-diazineyl)-2-hydroxybenzaldehyde (4), and 5-bromo-3-methoxy- 2-hydroxybenzaldehyde (5) with N-benzoylglycine (7), in good yield. Treatment of compound 8c with ammonia in the presence of anhydrous potassium carbonate to yield N-(5-bromo-8-methoxy-1-azocoumarin-3-yl) benzamide (9). Compound (9) was acetylated with acetic anhydride to give N-(2-acetoxy-5-bromo-8-methoxyquinolin-3-yl) benzamide (10). N-(substituted coumarin and azacoumarin-3-yl) benzamides (8-10) were tested for their in vitro cytotoxic activity against (HepG2) cell line. Furthermore, DNA flow cytometry investigation over HepG2 cells indicated that compound 8a demonstrated arrest at G1/S stages of the cell cycle and induction of apoptosis by rising pre-G1 stage. Compound 8a displayed a significant tubulin polymerization inhibition.
 
 KEY WORDS: Synthesis, Coumarin, Azacoumarin, Drugs, Cytotoxicity
 Bull. Chem. Soc. Ethiop. 2023, 37(4), 1003-1019. 
 DOI: https://dx.doi.org/10.4314/bcse.v37i4.16

DYNAMICS OF THE COMPOSITION OF ORGANIC EFFLUENTS FROM URBANIZED TERRITORIES OF KUZBASS INTO THE TOM RIVER

The composition and distribution of organic compounds in the bottom sediments of the Tom River near the city of Yurga (the Kemerovo Region - Kuzbass) in 1995, 2005 and 2018 are determined by gas chromatography - mass spectrometry. The compounds included hydrocarbons (n-alkanes, isoalkanes, naphthenes, alkylbenzenes, and polycyclic aromatic hydrocarbons), oxygen-containing compounds (carboxylic acids and their ethyl and propyl esters). The data on the group composition of the most dangerous pollutants, polycyclic aromatic hydrocarbons, are presented. The pattern of changes in the technogenic load on the river system made by the Kuzbass enterprises over different years has been established. The highest contribution to the pollution of the Tom basin was determined to be in 2005. This contribution is directly due to the industrial activities at the enterprises of Kuzbass.

New biodegradation degree proxies based on acids and neutral nitrogen- and oxygen-containing compounds characterized by high resolution mass spectrometry

Heavy oil is one of the most significant unconventional petroleum resources and one of its formation mechanisms is biodegradation. The characterization of the molecular compositions of petroleum is crucial for determining the various degrees of biodegradation. In this work, detailed investigations of acids and polar NSO compounds in different levels of biodegraded oils from the Bongor Basin (Chad) were carried out by negative ion electrospray ionization (-ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The present findings show that the heteroatomic compounds of biodegraded crude oils are predominantly composed of N1, N1O1, O1, O2, O3 and O4 species. The relative content of N1, N1O1 and O1 species tend to decrease and those of O2, O3 and O4 species appear to increase with the increasing of biodegradation. The ratio of acyclic and cyclic acids (A/C ratio) of the O2 species increase with an increase of biodegradation, indicating the increasing of O2 class during microbial alteration. A new parameter, i.e. the ratio of (O2 + O3 + O4)/(N1 + O1) species, is presented to quantificationally define biodegradation levels. This parameter is inversely proportional to API gravity and has a favorable positive correlation with total acid number (TAN), suggesting acidic compounds are formed by the microbial alteration of N1 and O1 class and are more presented in advanced biodegradation. A modified ternary diagram including N1, O1 and O2 + O3 + O4 species describe the detailed changes of nitrogen- and oxygen- containing compounds. Data points with a high level of biodegradation tend to shift to O2 + O3 + O4 species end-member and retreat from N1 species end-member, showing the relative content of O2 + O3 + O4 species increase and those of N1 species decrease with increasing biodegradation which may due to the formation of organic acids in degradation oil. The ratio of (O2 + O3 + O4)/(N1 + O1) species and the modified ternary diagram provide new parameters to estimate the biodegradation degree and TAN in crude oil.

Transcriptome Analysis of Roots from Wheat (Triticum aestivum L.) Varieties in Response to Drought Stress.

Under climate change, drought is one of the most limiting factors that influences wheat (Triticum aestivum L.) production. Exploring stress-related genes is vital for wheat breeding. To identify genes related to the drought tolerance response, two common wheat cultivars, Zhengmai 366 (ZM366) and Chuanmai 42 (CM42), were selected based on their obvious difference in root length under 15% PEG-6000 treatment. The root length of the ZM366 cultivar was significantly longer than that of CM42. Stress-related genes were identified by RNA-seq in samples treated with 15% PEG-6000 for 7 days. In total, 11,083 differentially expressed genes (DEGs) and numerous single nucleotide polymorphisms (SNPs) and insertions/deletions (InDels) were identified. GO enrichment analysis revealed that the upregulated genes were mainly related to the response to water, acidic chemicals, oxygen-containing compounds, inorganic substances, and abiotic stimuli. Among the DEGs, the expression levels of 16 genes in ZM366 were higher than those in CM42 after the 15% PEG-6000 treatment based on RT-qPCR. Furthermore, EMS-induced mutants in Kronos (T. turgidum L.) of 4 representative DEGs possessed longer roots than the WT after the 15% PEG-6000 treatment. Altogether, the drought stress genes identified in this study represent useful gene resources for wheat breeding.