Synthesis and efficiency of new pyridine, chromene and thiazole containing compounds as antimicrobial and antioxidant agents

ABSTRACT. The versatile scaffold, N'-(2-cyanoacetyl)-2-hydroxybenzohydrazide (3) was utilized in the production of new pyridine, chromene and thiazole derivatives as antimicrobial and antioxidant agents. The synthetic strategy involves the treatment of precursor 3 with various arylidene-malononitrile and 3-aryl-2-cyanoacrylate compounds to furnish substituted pyridines 5 and 7. The interaction of 3 with salicylaldehyde and/or phenyl isothiocyanate followed by cyclization with chloroacetone produced the corresponding 2-imino-2H-chromene-3-carbohydrazide and (thiazol-2-ylidene-acetyl)-salicylic acid hydrazide compounds 8 and 9, respectively. The structural features of the synthesized compounds were confirmed by using spectroscopic methods such as (IR, 1H NMR, 13C NMR and MS). The new pyridine, chromene and thiazole products showed potent antioxidants and antimicrobial activities. The thiazole derivative 9 exhibited the highest anti-bacterial and antifungal activities against S. aureus (75.0%) and B. subtilis (73.9%) and C. albicans (66.6%). The combination between salicylic acid hydrazide and thiazole moieties in the hybrid 9 indicated the best antioxidant activity (87.9%).                 KEY WORDS: Salicylic hydrazide, Arylidene-malononitrile, Pyridine, Thiazole, Antioxidant   Bull. Chem. Soc. Ethiop. 2022, 36(1), 137-148.                                                            DOI: https://dx.doi.org/10.4314/bcse.v36i1.12                                                      &nbsp

Synthesis of some new antipyrine-thiophene hybrids and their evaluations as antioxidant and antibacterial agents

ABSTRACT. A novel series of antipyrinyl thienyl ketones 4a-c, 7a-c, 10a-c, and 13a-b was chemically synthesized through the cyclocondensation of 4-chloroacetylantipyrine with various 2-substituted-thioacetanilide scaffolds, including 3-arylazo-4-mercapto-4-phenylamino-buten-2-ones, ethyl 2-arylazo-3-mercapto-3-phenylamino-acrylate, 2-cyano-3-mercapto-3-(phenylamino)-N-arylacrylamide, 4-mercapto-4-(phenylamino)but-3-en-2-one, and/or ethyl-3-mercapto-3-(phenylamino)acrylate. Indeed, the reaction of 4-chloroacetylantipyrine with 4-hydroxybenzaldehyde followed by refluxing with 2-cyanoacetohydrazide yielded 2-cyano-N'-(4-(2-(antipyrin-4-yl)-2-oxoethoxy)benzylidene)-acetohydrazide 17 as a building compound, which was used consequentially to synthesize a set of new antipyrinyl thienyl hybrids 19a-d. The chemical structures of newly synthesised compounds were unambiguously confirmed using extensive elemental and spectral data analyses. The newly synthesized compounds were screened for their antioxidant and antimicrobial activities. Compared to the test reference (Ascorbic acid, 88.0%), the antipyrinyl thienyl ketones 13a and 13b substituted with methyl and/or hydroxyl groups at the thiophene ring system displayed excellent antioxidant properties, 87.8% and 87.2%, respectively. Additionally, antipyrinyl thienyl ketones 13a and 13b showed high antibacterial activities, and their relative activity index (which ranges from 68% to 91.7%) was close to that of a reference compound, Ampicillin.   KEY WORDS: 4-Chloroacetylantipyrine, Thioacetanilide, Antipyrinyl thienyl ketones, Antioxidant, Antimicrobial   Bull. Chem. Soc. Ethiop. 2023, 37(1), 123-140.                                                              a DOI:https://dx.doi.org/10.4314/bcse.v37i1.1

5-(4-Fluoro­phen­yl)-3-[5-methyl-1-(4-methyl­phen­yl)-1H-1,2,3-triazol-4-yl]-4,5-dihydro-1H-pyrazole-1-carbothio­amide

In the title compound, C20H19FN6S, the pyrazole ring has an envelope conformation, with the methine C atom being the flap atom. The dihedral angle between the least-squares plane through the pyrazole and triazole rings is 7.59 (9)°, and the triazole and attached benzene ring form a dihedral angle of 74.79 (9)°. The thio­urea group is coplanar with the pyrazole ring [N—N—C—S torsion angle = −179.93 (11)°], which enables the formation of an intra­molecular N—H⋯N hydrogen bond. In the crystal, inversion-related mol­ecules associate via N—H⋯S hydrogen bonds and eight-membered {⋯HNCS}2 synthons feature in the crystal packing. These synthons are connected into supra­molecular chains along the a axis via N—H⋯F hydrogen bonds, and the chains are consolidated into layers in the ab plane via C—H⋯S and C—H⋯F contacts

Synthesis and biological assessment of new benzothiazolopyridine and benzothiazolyl- triazole derivatives as antioxidant and antibacterial agents

ABSTRACT. A novel series of benzothiazolopyridine derivatives was synthesized via interaction of -2-(benzothiazol-2-yl)-3-(4-chlorophenyl)acrylonitrile (2) with a diverse of commercially available reagents (indandione, thiobarbituric acid, and malononitrile). Moreover, a novel group of benzothiazole linked substituted 1,2,3-triazole derivatives were synthesized by exploring the chemical behavior of 5-benzothiazolyl-2-(4-chlorophenyl)-triazol-4-amine through refluxing in glacial acetic acid, condensation with phthalic anhydride, and cyanoacetylation reactions. All newly synthetized compounds have been tested for their antioxidant and antibacterial activities compared with ascorbic acid and Ampicillin as reference drugs, respectively. The benzothiazolo- pyridopyrimidine compound 6 was found the most potent antioxidant agent with IC50 = 0.015 mg/mL compared to the results of ascorbic acid (IC50 = 0.022 mg/mL). The investigated compounds showed no antibacterial properties against Gram-negative bacterial species, Pseudomonas aeruginosa and Escherichia coli. Benzothiazolopyridine derivative 5 displayed the best growth inhibition against Gram-positive bacteria, Staphylococcus aureus and Bacillus cereus with inhibition zones 24 and 20 mm, respectively.   KEY WORDS: Benzothiazole, Pyridobenzothiazole, 1,2,3-Triazole, Naphtharidine, Antioxidant   Bull. Chem. Soc. Ethiop. 2022, 36(2), 451-463.                                                              DOI: https://dx.doi.org/10.4314/bcse.v36i2.17                                                     &nbsp

RC beams under blast loads: Numerical simulation and machine learning modeling

AbstractThe use of explosives to target civilian buildings and other structures around the world is becoming a growing problem in modern societies. This paper focuses on RC beams exposed to free-air blast loads. The paper first presents a parametric study on the behavior of RC beams subjected to blast loads using finite element simulation and then proposes an Artificial Neural Network (ANN) model to predict that behavior in a simple and easy manner. The ABAQUS program is used to simulate RC beams under blast loads. Experimental data was collected from the literature and used to validate the ABAQUS models. Deflection, reaction forces, ultimate stress, ultimate strain, and failure mode of RC beams are investigated. The considered design parameters in the parametric study are the characteristic compressive strength of concrete (fcu), the transverse reinforcement ratio (ρT%), the longitudinal reinforcement ratio (ρL%), and the scaled distance (Z). In this paper, the proposed ANN model was trained and tested using datasets produced using ABAQUS. The input parameters of the ANN model are TNT weight, standoff distance (D), characteristic compressive strength of concrete, transverse reinforcement ratio, longitudinal reinforcement ratio, width-to-thickness ratio (b/t), and length-to-thickness ratio (L/t). The predicted behavior using the ANN model showed the credibility of the model. The results indicated that L/t, b/t, and Z have significant effects on the behavior of RC beams under blast loads compared with fcu, ρT%, and ρL%, the cracks area increases with the decrease in Z, fcu, and b/t and decreases with L/t decrease

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Novel Antimicrobial Agents: Fluorinated 2-(3-(Benzofuran-2-yl) pyrazol-1-yl)thiazoles

A new series of 2-pyrazolin-1-ylthiazoles 8a–d and 13–16 was synthesized by cyclization of N-thiocarboxamide-2-pyrazoline with different haloketones and 2,3-dichloroquinoxaline. The structures of the new compounds were confirmed by elemental analyses as well as NMR, IR, and mass spectral data. The newly synthesized compounds were evaluated for their antimicrobial activities, and also their minimum inhibitory concentration (MIC) against most of test organisms was performed. Amongst the tested ones, compound 8c displayed excellent antimicrobial activity

Utilization of 5-chloro-2-(cyanoacetamido)pyridines in the synthesis of biologically active heterocyclic hybrids

A simple synthesis for a series of chloropyridine derivatives incorporating heterocyclic hybrids has been accomplished. The key reaction involving employment of 5-chloro-2-(cyanoacetamido)pyridines 3 in the synthesis of chloropyridinyl-pyridone, chloropyridinyl-pyrazole, chloropyridinyl-thiazole and chloropyridinyl-thiophene hybrids. The newly synthesized heterocycles were evaluated for their antioxidant and antibacterial activities against Gram-positive and Gram-negative bacterial strains. 3-Amino-N-(3,5-dichloropyridin-2-yl)-1H-pyrazole-4-carboxamide (12 b) was found to be the most potent compound against Escherichia coli and Staphylococcus aureus exhibiting inhibition percent of 92.3 % and 100 %, respectively, when compared to the standard drug ampicillin. Moreover, compound 12 b displayed the most significant antioxidant activity with percent inhibition 87.8 % which is close to the antioxidant activity of ascorbic acid

Synthesis, molecular modelling, and antibacterial evaluation of new sulfonamide-dyes based pyrrole compounds

Abstract In this study, we synthesized new series of 5-oxo-2-phenyl-4-(arylsulfamoyl)sulphenyl) hydrazono)-4,5-dihydro-1H-pyrrole-3-carboxylate hybrids 4a-f with the goal of overcoming sulfonamide resistance and identifying novel therapeutic candidates by chemical changes. The chemical structures of the synthesized hybrids were established over the spectroscopic tools. The frontier molecular orbitals configuration and energetic possessions of the synthesized compounds were discovered utilizing DFT/B3LYP/6-311++ G** procedure. The 3D plots of both HOMO and LUMO showed comparable configuration of both HOMO and LUMO led to close values of their energies. Amongst the prepared analogues, the sulfonamide hybrids 4a-f, hybrid 4a presented potent inhibitory towards S. typhimurium with (IZD = 15 mm, MIC = 19.24 µg/mL) and significant inhibition with (IZD = 19 mm, MIC = 11.31 µg/mL) against E.coli in contrast to sulfonamide (Sulfamethoxazole) reference Whereas, hybrid 4d demonstrated potent inhibition with (IZD = 16 mm, MIC = 19.24 µg/mL) against S. typhimurium with enhanced inhibition against E. Coli, Additionally, the generated sulfonamide analogues’' molecular docking was estimated over (PDB: 3TZF and 6CLV) proteins. Analogue 4e had the highest documented binding score as soon as linked to the other analogues. The docking consequences were fitting and addressed with the antibacterial valuation