Acetic Anhydride Research Articles

Uncovering the role of unsaturated coordination defects in manganese oxides for concentrated solar-heating photothermal OVOCs oxidation: Experimental and DFT explorations

In this study, we innovatively develop a concentrated photothermal catalysis (CPTC) system with a cost-effective solar concentrator to efficaciously achieve light-to-heat conversion, and combine a defect engineering strategy to design Mn3O4-based catalysts with unsaturated coordination defects (O and Mn atoms) for solar-heating photothermal ethyl acetate oxidation without additional artificial-energy input. As a result, Mn3O4-3 exhibits outstanding photothermal catalytic performance for ethyl acetate and other OVOCs oxidation under weak simulated sunlight even natural sunlight irradiation. The enriched unsaturated defects in Mn3O4-3 with lower Mn-O and Mn-Mn coordination numbers not only improve the concentration of surface reactive species (Mn4+ and Oads), but also regulate the energy-band structure to further promote the light absorption capacity and charge separation. Experimental and theoretical evidences demonstrate that the generation of abundant Mn defects is conducive to the ethyl acetate dissociation/hydrolysis into key intermediates, while the existence of more O vacancies synergistically facilitates the O2 dissociation toward highly reactive O* participating in the deep oxidation of key intermediates. Moreover, in-situ DRIFTS and DFT results reveal the reaction pathway expansion (Pathway I and II) of photothermal ethyl acetate oxidation on manganese oxides under sunlight irradiation. This work provides an attractive CPTC technology for VOCs removal in energy and environmental application.

Genomic Insights into Syntrophic Lifestyle of 'Candidatus Contubernalis alkaliaceticus' Based on the Reversed Wood-Ljungdahl Pathway and Mechanism of Direct Electron Transfer.

The anaerobic oxidation of fatty acids and alcohols occurs near the thermodynamic limit of life. This process is driven by syntrophic bacteria that oxidize fatty acids and/or alcohols, their syntrophic partners that consume the products of this oxidation, and the pathways for interspecies electron exchange via these products or direct interspecies electron transfer (DIET). Due to the interdependence of syntrophic microorganisms on each other's metabolic activity, their isolation in pure cultures is almost impossible. Thus, little is known about their physiology, and the only available way to fill in the knowledge gap on these organisms is genomic and metabolic analysis of syntrophic cultures. Here we report the results of genome sequencing and analysis of an obligately syntrophic alkaliphilic bacterium 'Candidatus Contubernalis alkaliaceticus'. The genomic data suggest that acetate oxidation is carried out by the Wood-Ljungdahl pathway, while a bimodular respiratory system involving an Rnf complex and a Na+-dependent ATP synthase is used for energy conservation. The predicted genomic ability of 'Ca. C. alkaliaceticus' to outperform interspecies electron transfer both indirectly, via H2 or formate, and directly, via pili-like appendages of its syntrophic partner or conductive mineral particles, was experimentally demonstrated. This is the first indication of DIET in the class Dethiobacteria.

Porous rod-like Co(OH)F/Co3O4 heterojunction-based acetic anhydride gas sensor with high response and low operating temperature

In response to the pressing demand for acetic anhydride gas detection, this study introduces a novel gas sensor for precisely detecting acetic anhydride concentrations. The optimum conditions for the synthesis of cobalt hydroxyfluoride/cobalt oxide (CHFCO) heterojunctions with good acetic anhydride gas sensitivity were determined by carefully adjusting the calcination time, hydrothermal time and ammonium fluoride content. The best performing composite CHFCO sensor with porous rod particles was tested at 180 ℃ and achieved a response rate of 260 for 100 ppm acetic anhydride gas, with response and recovery times of 60 and 40 s, respectively. In comparison to other prepared sensors, the detection response for acetic anhydride was improved by a factor of 4.30–23.63. Moreover, the CHFCO sensor reliably detected acetic anhydride at a concentration of 500 ppb, exhibiting a response value of 1.56. Notably, the sensor demonstrated great selectivity, moisture resistance, and stability. The findings highlight the significant enhancements in gas-sensitive performance to acetic anhydride achieved by the abundant hydroxyl bonds on the surface of CHFCO heterojunction, the presence of fluorine ions, and the modulation of the band gap. These results provide valuable insights for the advancement of acetic anhydride gas sensors based on CHFCO heterojunction.

CARBON DIOXIDE CONVERSION OF METHANE ON LaNiO3 AND La0.9Ce0.1NiO3 PEROVSKITE CATALYSTS

Introduction. Perovskite type catalysts are becoming more and more relevant due to their stability to high temperature and sintering in the process of obtaining synthesis gas. Modification of perovskite catalysts with cerium can improve oxygen mobility and intensity of interaction with active metal particles. The purpose of this work is to study the activity of perovskite type catalysts LaNiO3 and La0.9Ce0.1NiO3 in the process of carbon dioxide conversion from methane to synthesis gas. Methodology. The catalyst was synthesized by the Pechini method, studied using the X-ray phase method and chromatographic analysis. Results of work. Catalyst La0.9Ce0.1NiO3 prepared by Pechini method can provide almost complete conversion of methane and carbon dioxide gas at the reaction temperature of 850°C (XCH4 98%, XCO2 93.6%). X-ray phase analysis shows that the synthesized LaNiO3 and La0.9Ce0.1NiO3 are oxide catalysts of the perovskite type, and have a typical structure of perovskites, forming phases LaNiO3 and CeO2. Conclusion. Studies have shown that varying the temperature of the reaction makes it possible to purposefully control the reaction in the direction of obtaining synthesis gas with a given ratio, to obtain valuable products such as acetic acid, acetic anhydride and ethylene glycol.

Preparation and characterization of corn cob cellulose acetate for potential industrial applications

Background: Locally generated biopolymers are amenable to further processing to widen their industrial applications. The study was aimed at generating low-cost cellulose acetate from corn cob residue and its characterizations for potential applications in biopolymer industries. Methods: Cellulose was extracted from the corn cob residue using the sodium hydroxide method. Acetylation of the cellulose to obtain corn cob cellulose acetate was carried out by adding appropriate quantities of a glacial acetic and acetylating mixture of acetic anhydride and sulphuric acid. The corn cob native cellulose and corn cob cellulose acetate were characterized using scanning electron microscopy (SEM) to examine their morphology, Fourier-transform infrared spectroscopy (FTIR) and powder X-ray diffraction (XRD) for structural elucidation while differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were employed to investigate their thermal properties. Results: - Two corn cellulose acetate samples with degree of substitutions 1.87 and 2.65 for samples CDA and CA respectively were obtained. They had improved solubilities in some organic solvents compared to the corn cob cellulose. The SEM examination showed the surface of the corn cob native cellulose (NC) was smooth and had a regular bundle-like structure while acetylation destroyed the original cellulose structure. Cellulose acetate samples showed a cluster-like structure with different sizes and a rough flake-like surface. FTIR and XRD studies showed that acetyl groups substituted cellulose hydroxyl groups. While FTIR study showed that the cellulose acetates had sharp bands between 1728 cm-1 to 1733 cm-1 and around 1368 cm-1 wavenumber unlike the corn cob cellulose sample, the data generated from XRD study indicated that acetylation of the corn cob cellulose led to 47% and 77% decrease in the crystallinity of CDA and CA samples respectively. The thermal analysis data from DSC and TGA studies confirmed that the acetylation improved the corn cob cellulose's thermal stability as indicated by the degradation of cellulose acetate samples at higher temperatures. Conclusion: The study concluded that low-cost cellulose acetate generated from corn cob residue could be potentially employed as a renewable, biodegradable, biocompatible polymer for industrial applications.

Modeling Wet Air Oxidation of Sodium Acetate in a Bubble Column

Scale-up bubble columns for wet air oxidation (WAO) represent a novel solution to the growing problem of sodium acetate-containing waste discharge. This study used an axial dispersion model to simulate a reactor at a high temperature of 320 °C. By minimizing the structure size and gas fed into the system, the estimated optimal reactor dimensions were obtained. At the optimized reactor diameter, total height, initial oxygen partial pressure, and superficial gas velocity of 1 m, 7 m, 40 bar, and 0.07 m/s, respectively, a degradation efficiency of over 90% was obtained, at which the residual concentration of sodium acetate degraded from 700 mol/m3 to 70 mol/m3. The axial distributions of the dissolved oxygen, sodium acetate, and oxygen concentrations in the gas were nearly uniform. The bubble column reactor exhibited an intermediate state between well-mixed flow and plug flow for both liquid and gas.

Synthesis, crystal structure, spectroscopic characterization, DFT calculations, Hirshfeld surface analysis, molecular docking, and molecular dynamics simulation investigations of novel pyrazolopyranopyrimidine derivatives

A series of new pyrazolopyranopyrimidine derivatives (3-9) were synthesized from 5-amino-2,4-dihydro-3-methyl-4-phenylpyrano-[2,3-c]pyrazole-5-carbonitrile (2) by multicomponent reactions (MCR) involving malononitrile, benzaldehyde, and pyrazolone under refluxing ethanol in the presence of piperidine. Compound (2) was then converted to 2-acetylpyrazolopyranopyrimidine (3) through a reaction with acetic anhydride. The deprotection of 3 using ammonium hydroxide in ethanol, leads to 4. Subsequent chlorination of 4 by phosphorus oxychloride affords 5 which was alkylated using methyl iodide and ethyl bromoacetate in DMF, leading to regioisomers 6-9. The products were characterized by spectroscopic techniques (1H and 13C NMR) and confirmed by single crystal X-ray diffraction (XRD) studies for 2, 5, 6, and 9. Moreover, the geometrical parameters, molecular orbital calculations, and spectral data of 2, 5, 6, and 9 were compared by DFT at the B3LYP/6-311G(d,p) level of theory. There is good agreement between the calculated results and the experimental data. The intermolecular contacts for 2, 5, 6, and 9 were studied by Hirshfeld surface analysis. In addition, the molecular docky study was conducted to investigate the binding patterns of 2, 5, 6, and 9 within the binding site of cyclin-dependent kinase 2 (CDK2) and penicillin-binding protein 1 A. After the docking process, molecular dynamics (MD) simulations for 100 ns were performed on CDK2 and PBP 1 A proteins in the complex with 5. Communicated by Ramaswamy H. Sarma

The roles of DGAT1 and DGAT2 in human myotubes are dependent on donor patho-physiological background.

The roles of DGAT1 and DGAT2 in lipid metabolism and insulin responsiveness of human skeletal muscle were studied using cryosections and myotubes prepared from muscle biopsies from control, athlete, and impaired glucose regulation (IGR) cohorts of men. The previously observed increases in intramuscular triacylglycerol (IMTG) in athletes and IGR were shown to be related to an increase in lipid droplet (LD) area in type I fibers in athletes but, conversely, in type II fibers in IGR subjects. Specific inhibition of both diacylglycerol acyltransferase (DGAT) 1 and 2 decreased fatty acid (FA) uptake by myotubes, whereas only DGAT2 inhibition also decreased fatty acid oxidation. Fatty acid uptake in myotubes was negatively correlated with the lactate thresholds of the respective donors. DGAT2 inhibition lowered acetate uptake and oxidation in myotubes from all cohorts whereas DGAT1 inhibition had no effect. A positive correlation between acetate oxidation in myotubes and resting metabolic rate (RMR) from fatty acid oxidation in vivo was observed. Myotubes from athletes and IGR had higher rates of de novo lipogenesis from acetate that were normalized by DGAT2 inhibition. Moreover, DGAT2 inhibition in myotubes also resulted in increased insulin-induced Akt phosphorylation. The differential effects of DGAT1 and DGAT2 inhibition suggest that the specialized role of DGAT2 in esterifying nascent diacylglycerols and de novo synthesized FA is associated with synthesis of a pool of triacylglycerol, which upon hydrolysis results in effectors that promote mitochondrial fatty acid oxidation but decrease insulin signaling in skeletal muscle cells.

Release efficiencies of potassium permanganate controlled-release biodegradable polymer (CRBP) pellets embedded in polyvinyl acetate (CRBP-PVAc) and polyethylene oxide (CRBP- PEO) for groundwater treatment

In-situ chemical oxidation (ISCO) is a commonly used method for the remediation of environmental contaminants in groundwater systems. However, traditional ISCO methods are associated with several limitations, including safety and handling concerns, rebound of groundwater contaminants, and difficulty in reaching all areas of contamination. To overcome these limitations, novel Controlled-Release Biodegradable Polymer (CRBP) pellets containing the oxidant KMnO₄ were designed and tested. The CRBP pellets were encapsulated in Polyvinyl Acetate (CRBP-PVAc) and Polyethylene Oxide (CRBP-PEO) at different weight percentages, baking temperatures, and time. Their release efficiency was tested in water, soil, and water and soil mixture media. Results showed that CRBP-PVAc pellets with 60 % KMnO₄ and baked at 120 °C for 2 min had the highest release percentage and rate across different conditions tested. Natural organic matter was also found to be an important factor to consider for in-field applications due to its potential reducing effect with MnO4−. Overall, the use of CRBP pellets offers an innovative and sustainable solution to remediate contaminated groundwater systems, with the potential to overcome traditional ISCO limitations. These findings suggest that CRBP pellets could provide sustained and controlled release of the oxidant, reducing the need for multiple injections and minimizing safety and handling concerns. This study represents an important step towards developing a new and effective approach for ISCO remediation.

Physicochemical, physiological and sensory characteristics of tomato fruit edible coating results from various modified sago starches

The development of edible coatings as a substitute for plastic is one of the efforts to protect tomato fruit damage by using sago starch (SS) which has been modified with sodium trimetaphosphate (STMP), sodium tripolyphosphate (STPP), STMP/STPP ratio: 99/1 and acetic anhydride. The research objective was to obtain modified sago starch concentrations (SS-STMP, SS-STPP, SS STMP/STPP ratio and SS Acetate) based on the physicochemical, physiological and sensory characteristics of edible coating tomatoes. Research using Completely Randomized Design and Randomized Block Design. Edible coating is made by making the modified SS concentration which consists of 7 levels, namely, 0%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, and 3.0% (w/v) with 3 repeated. The analysis variables include moisture content, total acid, weight loss, storage durability, and sensory. The results showed that the results of edible coating from modified sago starch at concentrations of 2 and 2.5% gave the best physicochemical, physiological and sensory characteristics.

Synthesis, in silico and in vitro antimicrobial efficacy of substituted arylidene-based quinazolin-4(3H)-one motifs.

Introduction: Quinazolin-4(3H)-one derivatives have attracted considerable attention in the pharmacological profiling of therapeutic drug targets. The present article reveals the development of arylidene-based quinazolin-4(3H)-one motifs as potential antimicrobial drug candidates. Methods: The synthetic pathway was initiated through thermal cyclization of acetic anhydride on anthranilic acid to produce 2-methyl-4H-3,1-benzoxazan-4-one 1, which (upon condensation with hydrazine hydrate) gave 3-amino-2-methylquinazolin-4(3H)-one 2. The reaction of intermediate 2 at its amino side arm with various benzaldehyde derivatives furnished the final products, in the form of substituted benzylidene-based quinazolin-4(3H)-one motifs 3a-l, and with thiophene-2-carbaldehyde to afford 3m. The purified targeted products 3a-m were effectively characterized for structural authentication using physicochemical parameters, microanalytical data, and spectroscopic methods, including IR, UV, and 1H- and 13C-NMR, as well as mass spectral data. The substituted arylidene-based quinazolin-4(3H)-one motifs 3a-m were screened for both in silico and in vitro antimicrobial properties against selected bacteria and fungi. The in silico studies carried out consisted of predicted ADMET screening, molecular docking, and molecular dynamics (MD) simulation studies. Furthermore, in vitro experimental validation was performed using the agar diffusion method, and the standard antibacterial and antifungal drugs used were gentamicin and ketoconazole, respectively. Results and discussion: Most of the compounds possessed good binding affinities according to the molecular docking studies, while MD simulation revealed their levels of structural stability in the protein-ligand complexes. 2-methyl-3-((thiophen-2-ylmethylene)amino) quinazolin-4(3H)-one 3m emerged as both the most active antibacterial agent (with an minimum inhibitory concentration (MIC) value of 1.95μg/mL) against Staphylococcus aureus and the most active antifungal agent (with an MIC value of 3.90μg/mL) against Candida albicans, Aspergillus niger, and Rhizopus nigricans.

H2 Production from Real Wastes of Polyethylene Terephthalate and Polylactic Acid using CNx/Ni2P Nanocatalyst

In this study, H2(g) production from real wastes of polyethylene terephthalate and polylactic acid using CNx/Ni2P nanocatalyst was investigated with photoreforming process. Optimum experimental conditions were found at ultrasonicated 4.8 mg/ml CNx/Ni2P nanocatalyst, at pre-treated 20 mg/ml polyethylene terephthalate, at pre-treated 20 mg/ml polylactic acid, at 4 ml aqueous 1 M KOH, at 10 ml internal volume of sealed photoreactor under anaerobic conditions, at 1200 W Xe solar lamp, at 60 h photoreforming solar irradiation time, at AM 1.0G, at 150 mW/cm2, at 25°C, respectively. XRD, FESEM, EDX, FTIR, TEM, DRS and XPS analyzes were performed for characterization studies of microplastics. Polyethylene terephthalate and polylactic acid measurements were measured in inductively coupled plasma mass spectrometry (ICP-MS). H2(g) measurements were made in gas chromatography–mass spectrometry (GC-MS). The maximum 41.40 ± 5.10 and 48.60 ± 3.12 µmol H2 / gsub yields were measured for CNx=20 mg/ml and for Ni2P=20 mg/ml, respectively. The maximum 18.26 ± 1.18 and 52.41 ± 7.29 µmol H2 / gsub H2(g) production yields were found for non-sonicated CNx/Ni2P and ultra-sonicated CNx/Ni2P nanocatalyst, respectively, after 24 h photoreforming solar irradition time. The maximum 123.75 ± 11.92 and 267.41 ± 24.65 µmol H2 / gsub H2(g) production yield was measured for polyethylene terephthalate and polylactic acid, respectively, after 60 h photoreforming solar irradiation time. The maximum 6.57 ± 0.87Percentage and 2.43 ± 0.38Percentage stoichiometric H2 conversion yields were observed for polyethylene terephthalate and polylactic acid, respectively, after 60 h photoreforming solar irradition time. The maximum 96 and 57 μmol H2 / gsub H2(g) yields for polyethylene terephthalate were obtained over CNx/Ni2P and H2NCNx/Ni2P, respectively, after 60 h photoreforming solar irradiation time. The maximum 182 and 173 μmol H2 / gsub H2(g) yields for polylactic acid were observed over CNx/Ni2P and H2NCNx/Ni2P, respectively, after 60 h photoreforming solar irradiation time. The maximum 4.85 ± 0.62, 88.37 ± 10.74, 26.55 ± 1.95, 21.94 ± 1.86, 75.30 ± 9.34, 60.07 ± 5.11 and 14.61 ± 2.14 μmol H2 / gsub H2(g) production yields were obtained for Acetate, Ethylene glycol, Formate, Glycolate, Glyoxal, Lactate and Terephthalate oxidation intermediates, respectively, after 24 h photoreforming solar irradiation times. 126 nmol Acetate, 131 nmol Formate, 5 nmol Glycolate and 6200 nmol Glyoxal organic oxidation intermediates for polyethylene terephthalate with CNx/Ni2P nanocatalyst were found after 7 days photoreforming solar irradiation time. 67 nmol Acetate and 63 nmol Formate organic oxidation intermediates for polylactic acid with CNx/Ni2P nanocatalyst were obtained after 7 days photoreforming solar irradiation time. Photoreforming process is a very effective, easy to apply, economical and environmentally friendly method for the removal of plastic and microplastic wastes.

Antibacterial Calcium Phosphate Coatings for Biomedical Applications Fabricated via Micro-Arc Oxidation.

A promising method for improving the functional properties of calcium-phosphate coatings is the incorporation of various antibacterial additives into their structure. The microbial contamination of a superficial wound is inevitable, even if the rules of asepsis and antisepsis are optimally applied. One of the main problems is that bacteria often become resistant to antibiotics over time. However, this does not apply to certain elements, chemical compounds and drugs with antimicrobial properties. In this study, the fabrication and properties of zinc-containing calcium-phosphate coatings that were formed via micro-arc oxidation from three different electrolyte solutions are investigated. The first electrolyte is based on calcium oxide, the second on hydroxyapatite and the third on calcium acetate. By adding zinc oxide to the three electrolyte solutions, antibacterial properties of the coatings are achieved. Although the same amount of zinc oxide has been added to each electrolyte solution, the zinc concentration in the coatings obtained vary greatly. Furthermore, this study investigates the morphology, structure and chemical composition of the coatings. The antibacterial properties of the zinc-containing coatings were tested toward three strains of bacteria-Staphylococcus aureus, methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. Coatings of calcium acetate and zinc oxide contained the highest amount of zinc and displayed the highest zinc release. Moreover, coatings containing hydroxyapatite and zinc oxide show the highest antibacterial activity toward Pseudomonas aeruginosa, and coatings containing calcium acetate and zinc oxide show the highest antibacterial activities toward Staphylococcus aureus and methicillin-resistant Staphylococcus aureus.

Synthesis and Antioxidant Activity of Some Benzoquinoline-Based Heterocycles Derived from 2-((3-Chlorobenzo[f]quinolin-2-yl)methylene)hydrazine-1-carbothioamide

A new series of benzoquinoline-based heterocycles was synthesized utilizing the building block synthon, 2-((3-chlorobenzo[f]quinolin-2-yl)methylene)hydrazine-1-carbothioamide via the condensation of 3-chlorobenzo[f]quinoline-2-carbaldehyde with thiosemicarbazide. The titled thiosemicarbazone scaffold was conducted with some carbon-centered electrophilic reagents such as acetic anhydride, chloroacetyl chloride, chloroacetic acid, 2-bromo-1-(3-nitrophenyl)ethan-1-one, 2-chloro-N-phenylacetamide, and dimethyl but-2-ynedioate to achieve triazolethione, imidazolone, thiazolidinone, and thiazole derivatives. In turn, the hydrazinolysis of this substrate did not proceed as expected but it afforded the azine derivative. The antioxidant activity screening of the produced compounds revealed that thiazole and triazolethione derivatives were the most potent.

Rapid On-Resin N-Formylation of Peptides as One-Pot Reaction.

N-formylation is a common pre- and post-translational modification of the N-terminus or the lysine side chain of peptides and proteins that plays a role in the initiation of immune responses, gene expression, or epigenetics. Despite its high biological relevance, protocols for the chemical N-formylation of synthetic peptides are scarce. The few available methods are elaborate in their execution and the yields are highly sequence-dependent. We present a rapid, easy-to-use one-pot procedure that runs at room temperature and can be used to formylate protected peptides at both the N-terminus and the lysine side chain on the resin in near-quantitative yields. Only insensitive, storage-stable standard chemicals - formic acid, acetic anhydride, pyridine and DMF - are used. Formylation works for both short and long peptides of up to 34 amino acids and over the spectrum of canonical amino acids.

New attempts on acidic anaerobic digestion of poly (butylene adipate-co-terephthalate) wastewater in upflow anaerobic sludge blanket reactor

Poly (butylene adipate-co-terephthalate) (PBAT) wastewater is a highly concentrated, acidic, and toxic wastewater generated from biodegradable plastics production. Large amounts of alkali would be consumed when treating PBAT wastewater by anaerobic digestion due to the low pH value. This study employed acidic anaerobic digestion to treat PBAT wastewater and compared to neutral anaerobic digestion. The results indicated that the COD removal rates in the acidic upflow anaerobic sludge blanket (UASB) reactor were 65.5% and 59.9%, respectively at influent pH 6.0 and 5.0 with the COD concentration of around 11,000 mg L−1, and the methane conversion efficiency were 172.5 and 183.8 mLCH4/gCODr (gCODr: COD removed amount), respectively. Correspondingly, the average COD removal and methane conversion efficiency in the neutral UASB reactor were 63.2% and 188.0 mLCH4/gCODr, respectively. The treatment efficiency of acidic and neutral UASB reactors for PBAT wastewater was similar. The hydrogenotrophic methanogenic activity was further enhanced in the acidic UASB reactor compared to the neutral one. The increase of alkalinity in the acidic UASB reactor (2.4 mmol L−1) was higher than the neutral (2.0 mmol L−1). A higher level of syntrophic acetate oxidation bacteria and hydrogenotrophic methanogen was enriched in the acidic UASB reactor, ensuring efficient treatment and saving costs.

Synthesis, spectroscopic, DFT calculations, biological activity, SAR, and molecular docking studies of novel bioactive pyridine derivatives

Enaminonitrile pyridine derivative was used as a precursor for preparation of fourteen heterocyclic compounds using both conventional thermal and microwave techniques. Diverse organic reagents, such as chloroacetyl chloride, acetic anhydride, chloroacetic acid, carbon disulfide, p-toluene sulfonyl chloride, maleic anhydride, phthalic anhydride, were used. The chemical formulae and structures of isolated derivatives were obtained using different analytical and spectroscopic techniques such as IR, 1H-, 13C-NMR as well as mass spectrometry. The spectroscopic analyses revealed diverse structure arrangements for the products. Molecular structure optimization of certain compounds were performed by the density functional theory (DFT/B3LYP) method and the basis set 6–31 G with double zeta plus polarization (d,p). The antimicrobial inhibition and the antioxidant activity of the reported compounds were screened. Compounds 5, 6, 11 and 13 exhibited the highest antibacterial inhibition, while compound 8 gave the highest scavenging activity (IC50 43.39 µg/ml) against the DPPH radical. Structure–activity relationship of the reported compounds were correlated with the data of antibacterial and the antioxidant activity. The global reactivity descriptors were also correlated with the biological properties of compounds. The molecular docking studies of reported compounds were investigated, and the analysis showed that the docked compounds have highly negative values for the functional binding scores. The binding interaction was found to be correlated with the substituent fragments of the compounds.

Direct Deoxygenation of α-Hydroxy and α,β-Dihydroxy Ketones Using a Silyl Lithium Reagent.

A reliable method for the one-step direct deoxygenation of α-hydroxy ketones has been developed using a silyl lithium reagent and acetic anhydride. The method is metal-catalyst-free and does not require prefunctionalization of the hydroxy group prior to its removal. Deoxygenation of different primary, secondary, and tertiary alcohols was carried out with up to 98% isolated yield. Additionally, double deoxygenation was achieved when the present method was applied to α,β-dihydroxy ketones to access the corresponding enones in a single step.

Novel Thiazolactone Derivatives: Synthesis and Quantum Chemical Study

In this research, 15 novel derivatives of the thiazolactone skeleton were synthesized using the Erlenmeyer–Plöchl reaction procedure. Glycine, alanine and leucine amino acids were used to make dithiocarbamate precursor by reacting amino acids with carbon disulfide and benzyl chloride. Obtained benzyl dithiocarbamate underwent thiazolactone formation in the presence of acetic anhydride and then condensed with arylglyoxals as condensing carbonyl group source. Products were characterized using their spectroscopic IR, 1H NMR, and 13C NMR data. In continuation, computational chemistry methods were used to get some information about the products such as structural characteristics, charge distribution, 1H NMR and UV-visible spectra. Results showed that the calculated chemical shifts are in good agreement with experimentally recorded ones. The B3LYP density functional method in conjunction with the 6-311++G(d,p) basis set was used for all calculations.

Synthesis, spectroscopic characterizations and cytotoxic activities of some novel 1,2-bis-(tetrasubstituted-benzylidene) hydrazine analogues

ABSTRACT. The present work describes an efficient and convenient synthesis of a library of novel 1, 2-bis-(tetrasubstituted-benzylidene) hydrazine an analogue (3-7) 1,2-bis (3-methoxy-2-hydroxybenzlidene) hydrazine (3) and 1,2-bis (6-bromo-3-methoxy 2-hydroxybenzylidene) hydrazine (4), were obtained via opening of ester coumarin derivatives (1 and 2) with hydrazine hydrate under reflux. Diazotization of compound 4 with aryldiazonium chloride led to the formation of 1,2-bis (6-bromo-5-arylazo-3-methoxy-2-hydroxybenzylidene) hydrazine (6a,b). Acetylation of compounds 4 and 6a with acetic anhydride afforded the corresponding 1,2-bis (6-bromo-5-substituted-3-methoxy-2-acetoxy benzylidene) hydrazines (5 and 7). The cytotoxicity screening of some synthesized 1,2-bis (tetra substituted benzylidene) hydrazines (4-7) against breast cancer cell lines (MCF-7), and it was found several active compounds. Meanwhile compound 5 exhibited cytotoxic activity compared to reference drug. The DNA flow cytometry on MCF-7 cells of compound 5 was determined, it was found to cause G2/M phase arrest and induce apoptosis in all G1/M phases. In addition, compound 5 has been tested in other trials against aromatase inhibitors and tyrosinase inhibitors.
 KEY WORDS: Synthesis, Hydrazine derivatives, 1H NMR, Mass spectra, MCF-7 cell lines, Cytotoxicity
 Bull. Chem. Soc. Ethiop. 2023, 37(6), 1503-1520.DOI: https://dx.doi.org/10.4314/bcse.v37i6.16