Design, green one-pot synthesis and molecular docking study of novel N,N-bis(cyanoacetyl)hydrazines and bis-coumarins as effective inhibitors of DNA gyrase and topoisomerase IV

Recent advancements in the development of next-generation dual-targeting antibacterial agents

DNA gyrase and topoisomerase IV are validated targets for developing dual-targeting antibacterial agents. The development of novel molecules targeting both enzymes has gained tremendous importance in circumventing the development of bacterial resistance. In the present review, we highlight the recent developments and discovery of dual-targeting inhibitors over the last five years. The structure-activity relationships, molecular docking analysis, and pharmacological activity are presented to facilitate the rational design and development of novel dual-targeting inhibitors to bridge the gap in antibiotic drug discovery.

Synthesis, antibacterial evaluation and in silico studies of novel 2-(benzo[d]thiazol-2-yl)-N-arylacetamides and their derivatives as potential DHFR inhibitors

Novel N-arylacetamides 2a-f were synthesized based on benzo[d]thiazole scaffold. The compounds 2a-c underwent Knoevenagel condensation through green synthetic method with different aromatic aldehydes and pyrazole-7-carbaldehydes delivered the respective arylidenes with efficient yields. Arylidenes 4 reacted with malononitrile affording the corresponding N-arylpyridones 11a-i. Moreover, the reaction of 2a-c with each of salicylaldehyde and 5-arylazo salicylaldehydes afforded the unexpected coumarins rather than quinolin-5-ones. The structure of coumarin 8 was confirmed by density functional theory (DFT) calculations using basis set B3LYP/6-311 G +  + (d,p) to obtain the suitable geometrical structure with molecular orbitals` energies revealing its planar structure and its agreement with experimental data. Besides, the antibacterial activity was tested against different bacterial strains revealing potent activity especially Gram-negative bacteria with excellent minimum inhibition concentration (MIC) value ranging from 31.25 to 250 µg/L. Additionally, compounds 2c and 4m showed enzyme inhibition against dihydrofolate reductase in Escherichia coli with greater potency (IC50 for 2c = 3.796 µM, IC50 for 4m = 2.442 µM) than the standard antibiotic trimethoprim (IC50 = 8.706 µM). Investigation of the physicochemical properties of the newly compounds exhibited their better ADME properties that can be developed for the discovery of new antibacterial agents.

Phytochemical Characterization and Antibacterial Activity of Carthamus Caeruleus L. Aqueous Extracts: In Vitro and In Silico Molecular Docking Studies

In order to valorize natural resources and the traditional use of medicinal plants in Algeria, this study exploits the antibacterial effect of Carthamus caeruleus L. Since there are few studies on this plant despite its notable therapeutic potential, this work aims to characterize the chemical composition of Carthamus caeruleus L. leaf and root aqueous extracts and to evaluate their antibacterial activity through an in vitro and in silico studies. Spectrophotometric assays and HPLC results revealed 22 components in the roots and 16 in the leaves. Disc diffusion and microdilution methods were used to study the antibacterial properties against nine standard bacterial strains. The results showed that roots exhibited the best activity on most tested strains. Both extracts were also able to inhibit the growth of Staphylococcus aureus ATCC 25923 and Escherichia coli ATSC 25922. Furthermore, no nucleic acid leakage or membrane damage was detected. However, molecular docking of the molecules indicates that some constituents have significant affinity and stability for DNA gyrase. Gallic acid, luteolin, myricetin, and orientin were found to have the highest score. The molecular docking data suggest, for the first time, that the antibacterial activity may be caused by the inhibition of DNA gyrase.

Design, synthesis of some novel coumarins and their nanoformulations into lipid-chitosan nanocapsule as unique antimicrobial agents

Developing and creating novel antibiotics is one of the most important targets in treating infectious diseases. Novel coumarins were synthesized and characterized using different spectroscopic techniques such as Fourier Transform Infrared (FTIR), Nuclear magnetic resonance1H and 13C and mass spectroscopy (MS). All of the synthesized compounds have been tested for activity and sensitivity against the microbial strains of B. subtilis, S. aureus, E. coli, P. aeruginosa, S. typhi, and C. albicans. All compounds showed substantial results against the tested microbes except S. typhi, which was not affected in any way by these coumarins. Exceptional results were shown by compounds 4, 6d, and 8b, which made them the best candidates for loading to the vicinity of nanostructure lipid carrier and coated by chitosan nanocapsule (NLC-Cs). Transmission electron microscope (TEM) confirmed spherical morphology with particles size less than 500 nm. Also, dynamic light scattering (DLS) were utilized to measure the average particle size (between 100 and 200 nm) and the stability assessed by zeta potential were found to be more positive confirming the chitosan encapsulation. Antimicrobial activity assessments were performed for both synthetic compounds and their NLCs analogues. The nanoformulation of 4-NLC-Cs, 6d-NLC-Cs, and 8b-NLC-Cs manifested unique biological results, especially 8b-NLC-Cs, which revealed powerful effects over all the tested organisms including S. typhi. The increasing biological effect of the drugs in their nanoscale form is reflected in the increasing value of inhibition zone diameter and suppressing the value of MIC to reach record levels like 8b-NLC-Cs disclosed MIC = 0.48 and 0.24 µg/ml against S. aureus and C. albicans, respectively, by the mean 8b-NLC-Cs nanoformulation suppressed the MIC by 65 folds of its initial value before nano. In continuation, it was proven that the compounds 4, 6d and 8b were found to make noticeable changes on the DNA-Gyrase levels with reduced IC50 values particularly 8b showed excellent inhibitory effect with IC50 = 4.56 µM. TEM was used to pursue the morphological changes that occur in bacterial cells of P. aeruginosa. The weakness of the cell wall in most bacterial cells treated with nanomaterials, 8b-NLC-Cs, has reached the point of the cell wall rupture and the cell components spilling out of the cells causing necrotic cell death.

Multimodal antibacterial potency of newly designed and synthesized Schiff's/Mannich based coumarin derivatives: potential inhibitors of bacterial DNA gyrase and biofilm production

The briskened urge to develop potential antibacterial candidates against multidrug-resistant pathogens has motivated the present research study. Herein, newly synthesized coumarin derivatives with azomethine and amino-methylated as the functional groups have been focused on their antibacterial efficacy. The study proposed two distinct series: 3-acetyl substituted coumarin derivatives, followed by the Schiff base approach (5a-5i), and formaldehyde-secondary cyclic amine-based derivatives (7a-7g), using the Mannich base approach, further the compounds have been confirmed through various spectral studies. Further, target-specific binding affinity has been affirmed via in silico study. In vitro antibacterial study suggested compounds 5d and 5f to be most effective against S. aureus and multidrug-resistant K. pneumoniae, with MIC values of 8 and 16 μg mL-1. Among them, the compounds 5d and 5f showed excellent binding scores against different bacterial gyrase compared to the standard novobiocin. Based on RMRS, RMSF, Rg, and H-bond plots, MD simulation study at 100 ns also suggested better stability of 5d inside gyraseB of E. coli than the complex of E. coli-GyrB-novobiocin. The toxicity and pharmacokinetic profiles showed favorable drug-likeness. Overall, systematic in vitro and in silico assessment suggested that multimodal antibacterial derivatives 5d and 5f strongly inhibit both bacterial DNA gyrase and biofilm formation of drug-resistant pathogens, suggesting their potency in mainstream antibacterial therapy.

Synergistic and potential antifungal properties of tailored, one pot multicomponent monoterpenes co-delivered with fluconazole encapsulated nanostructure lipid carrier

Frequent and variant infections are caused by the virtue of opportunistic fungi pathogens. Candidiasis, aspergillosis, and mucormycosis are pathogenic microorganisms that give rise to vast fungal diseases that alternate between moderate to fatal in severity. The use of fluconazole as an antifungal drug was limited due to the acquired resistance in some types of Candida and other fungal species. This study aims to consolidate fluconazole's biological effectiveness against several pathogenic fungi. Six active monoterpenes (MTs) of carvacrol, linalool, geraniol, α-terpinene, citronellal, and nerolidol were selected and encapsulated in nanostructure lipid carrier (NLC) with (NLC-Flu-MTs) and/without (NLC-MTs) fluconazole in one nanoformulation to determine if they will act synergistically or not? The synthesized nanoformulation NLC-Flu-MTs and NLC-MTs exhibited very good particle size of 144.5 nm and 138.6 nm for size and zeta potential values of (- 23.5 mV) and (- 20.3 mV), respectively. Transmission electron microscope investigation confirmed that the synthesized NLCs have regular and spherical shape. The abundance and concentration of the six released monoterpenes were determined, as a novel approach, using GC-MS with very good results and validity. In-vitro antifungal screening was done before and after nano co-delivery against seven pathogenic, and aggressive fungi of Candida tropicalis, Candida krusei, Candida glabrata, Geotrichum Candidum, Candidaalbicans, Aspergillus Niger, and mucor circinelloides. Inhibition Zone diameter (IZD) and the minimum inhibitory concentration (MIC) were measured. Nanoformulations NLC-Flu-MTs and NLC-MTs manifested potential and unique biological susceptibility against all the tested microorganisms with reduced (MIC) values, especially against Candida Tropicalis (MIC = 0.97 µg/ml) which represents 16-fold of the value shown by NLC-MTs (MIC = 15.6 µg/ml) and 64-fold of fluconazole free before nanoformulation (MIC = 62.5 µg/ml). The efficiency of nanomaterials, particularly NLC-Flu-MTs, has become evident in the diminishing value of MIC which affirmed the synergism between fluconazole and the other six monoterpenes.

Synthesis, anticancer evaluation, molecular docking and ADME study of novel pyrido[4',3':3,4]pyrazolo[1,5-a]pyrimidines as potential tropomyosin receptor kinase A (TrKA) inhibitors

The starting compound 3-amino-1,7-dihydro-4H-pyrazolo[4,3-c]pyridine-4,6(5H)-dione (1) is reacted with each of diketone and β-ketoester, forming pyridopyrazolo[1,5-a]pyrimidines 4a,b and 14a,b, respectively. The compounds 4 and 14 reacted with each of aromatic aldehyde and arenediazonium salt to give the respective arylidenes and arylhydrazo derivatives, respectively. The structure of the new products was established using spectroscopic techniques. The cytotoxic activity of selected targets was tested in vitro against three cancer cell lines MCF7, HepG2 and HCT116. The data obtained from enzymatic assays of TrKA indicated that compounds 7b and 16c have the strongest inhibitory effects on TrKA with IC50 = 0.064 ± 0.0037 μg/ml and IC50 = 0.047 ± 0.0027 μg/ml, respectively, compared to the standard drug Larotrectinib with IC50 = 0.034 ± 0.0021 μg/ml for the HepG2 cancer cell line. In cell cycle analysis, compounds 7b, 15b, 16a and 16c caused the greatest arrest in cell cycle at the G2/M phase. In addition, compound 15b has a higher apoptosis-inducing effect (36.72%) than compounds 7b (34.70%), 16a (21.14) and 16c (26.54%). Compounds 7b, 16a and 16c were shown fit tightly into the active site of the TrKA kinase crystal structure (PDB: 5H3Q). Also, ADME study was performed on some selected potent anticancer compounds described in this study.

Schematic-portfolio of potent anti-microbial scaffolds targeting DNA gyrase: Unlocking ways to overcome resistance

Drug development process demands validation of specific drug target impeding the Multi Drug Resistance (MDR). DNA gyrase, as a bacterial target has been in trend for developing newer antibacterial candidates due to its absence in higher eukaryotes. The fluoroquinolones are the leading molecules in the drug discovery pipeline for gyrase inhibition due to its diversity. The fluoroquinolones like levofloxacin and moxifloxacin have been listed in class A drugs for treating MDR. Gatifloxacin and ciprofloxacin also proved its efficacy against MDR TB and MDR enteric fever in adults, whereas nemonoxacin can induce anti-MDR activity of other antibiotics already suggested by studies. Though fluoroquinolones already proved its effectiveness against gyrase, other molecules viz., benzothiazinone, phenyl pyrrolamide, substituted oxadiazoles, triazolopyrimidine, arylbenzothiazole, coumarinyl amino alcohols and ciprofloxacin uracil, can inhibit the target more precisely. The structure-activity-relationships of the different scaffolds along with their synthetic strategies have been deciphered in the current review. Also, the naturally occurring compounds along with their extraction procedure have also been highlighted as potent DNA gyrase inhibitors. In addition to fluoroquinolone, the natural compounds novobiocin and simocyclinone could also inhibit the gyrase, impressively which has been designed with the gyrase structure for better understanding. Herein, ongoing clinical development of some novel drugs possessing triazaacenaphthylenes, spiropyrimidinetriones, and oxazolidinone-quinolone hybrids have been highlighted which could further assist the future generation antibiotic development corroborating gyrase as a potential target against MDR pathogens.

Synthesis and Biological Evaluation of Benzothiazolyl-pyridine Hybrids as New Antiviral Agents against H5N1 Bird Flu and SARS-COV-2 Viruses

A novel series of benzothiazolyl-pyridine hybrids 8a-h and 14a-e were produced from the reaction of enamine derivative 4 with each of the arylcyanoacetamides 5a-h and cyanoacetohydrazides 9a-e. The new products were characterized by spectral techniques (IR, 1H NMR, 13C NMR, and MS). Biological evaluation of 8a-h and 14a-e in vitro against H5N1 and SARS-COV-2 viruses showed that several compounds had significant activity. Compounds 8f-h, which contain fluorine atoms, have better activity against H5N1 and anti-SARS-CoV-2 viruses than the other compounds included in this study. Compound 8h has a trifluoromethyl group at position-3 of the phenyl ring and exhibits a high activity against H5N1 virus with 93 and 60% inhibition at concentrations of 0.5 and 0.25 μmol/μL, respectively, among the tested compounds, and it also showed anti-SARS-CoV-2 virus with a half-maximum inhibition rate of 3.669 μM, among the remaining compounds. The mechanism of action of 8f-h, which is expected to be repurposed against COVID-19, was investigated. The results showed that the compounds have virucidal effects at different stages of the three mechanisms of action. Furthermore, compounds 8f-h were found to possess CoV-3CL protease inhibitory activities with IC50 values of 544.6, 868.2, and 240.6 μg/mL, respectively, compared to IC50 = 129.8 μg/mL of the standard drug lopinavir. Interestingly, compounds 8f-h also showed high inhibitory activity against the H5N1 virus as well as the SARS-CoV-2 virus. Moreover, compounds 8f-h fit admirably into the active site of the SARS-CoV-2 main protease (PDB ID: 6LU7) using the molecular docking Moe software 2015.10.

Design, Synthesis, Anticancer Evaluation and Molecular Modeling Studies of New Thiazolidinone-Benzoate Scaffold as EGFR Inhibitors, Cell Cycle Interruption and Apoptosis Inducers in HepG2

Synthesis of new anticancer candidates with protein kinases inhibitory potency is a major goal of pharmaceutical science and synthetic research. This current work represents the synthesis of a series of substituted benzoate-thiazolidinones. Most prepared thiazolidinones were evaluated in vitro for their potential anticancer activity against three cell lines by MTT assay, and they found to be more effective against cancer cell lines with no harm toward normal cells. Thiazolidinones 5 c and 5 h were further evaluated to be kinase inhibitors against EGFR showing effective inhibitory impact (with IC50 value; 0.2±0.009 and 0.098±0.004 μM, for 5 c and 5 h, respectively). Furthermore, 5 c and 5 h have effects on cell cycle and apoptosis induction capability in HepG2 cell lines by DNA-flow cytometry analysis and annexin V-FITC apoptosis assay, respectively. The results showed that they have effect of disrupting the cell cycle and causing cell mortality by apoptosis in the treated cells. Moreover, molecular docking studies showed better binding patterns for 5 c and 5 h with the active site of the epidermal growth factor receptor (EGFR) protein kinase (PDB code 1M17). Finally, toxicity risk and physicochemical characterization by Osiris method was performed on most of the compounds, revealing excellent properties as possible drugs.

Novel Thiopyrano[2,3-d]thiazole-pyrazole Hybrids as Potential Nonsulfonamide Human Carbonic Anhydrase IX and XII Inhibitors: Design, Synthesis, and Biochemical Studies

In recent years, molecular hybridization strategies have developed into a potent strategy for drug discovery. A series of novel thiopyrano[2,3-d]thiazoles linked to the pyrazole moiety was designed and developed as anticancer agents by a molecular hybridization. Target compounds were synthesized and characterized by spectroscopic tools as well as X-ray crystallography analysis as in the case of thiopyrano[2,3-d]thiazole derivative 5a. The MTT assay was used to demonstrate the in vitro efficacy of compounds 5a-g and 7a-j on MCF-7 and HePG-2. The results showed that some cycloadducts such as bromophenyl-4-thioxo-2-thiazolidinone 3e, 4-methylphenyl derivative of thiopyrano[2,3-d]thiazole 5d, and 6-substituted-thiopyrano[2,3-d]thiazoles 7e-j displayed good to excellent IC₅₀ in the range of 10.08 ± 1.5 to 25.95 ± 2.8 μg/mL against the MCF-7 cell line and from 7.83 ±2.1 to 13.37 ± 1.2 μg/mL against the HePG-2 cell line. To explore the enzymatic tests for isozymes hCAIX and hCAXII, the most promising eight compounds 3e, 5d, and 7e-j with IC₅₀ ranging from 7.83 ± 2.1 to 25.95 ± 2.8 μM were chosen. Compound 7e exhibited an IC₅₀ (0.067 ± 0.003 μM) similar to that of the standard drug AZA against CAIX (0.059 ± 0.003 μM)). For CAXII, the compound 7i had an IC₅₀ equal to 0.123 ± 0.007 μM compared to that of AZA (0.083 ± 0.005 μM). In addition, using flow cytometry, cell cycle analysis and apoptosis studies in HePG-2 were performed for the two potent anticancer and selective carbonic anhydrase agents (7e and 7i). An enzymatic assay of these two compounds against caspase-9 was also examined. Interestingly, the molecular docking studies revealed that compounds 7e and 7i successfully embedded themselves in the active pockets of the CAIX and CAXII enzymes through different interactions. Overall, the novel thiopyrano[2,3-d]thiazole-pyrazole hybrids (7e and 7i) were suggested to be potent and selective inhibitors of CAIX and CAXII.

ZnO Nanoparticle-Assisted Synthesis of Thiazolo[3,2-α]Pyrimidine Analogs: Antibacterial and Antioxidant Activity, In Silico Molecular Docking, and ADMET Prediction Study

In the present study, a new series of nine Thiazolo[3,2-α] pyrimidine analogs were synthesized in good to excellent yields (87.9–96.9%) and improved reaction time using a ZnO nanoparticle-assisted protocol. All the synthesized compounds were characterized using a combination of physicochemical parameters, UV-visible, 1H-NMR, and 13C-NMR spectroscopic methods. Among the synthesized compounds, the in vitro antibacterial activity displayed by compound 16 was higher (14.67 ± 0.58 mm at 500 μg/mL) against P. aeruginosa compared to amoxicillin (12.33 ± 0.58 mm at 500 μg/mL), whereas compounds 14 and 18 showed comparable activity (12.00 ± 0.00 mm and 12.33 ± 0.58 mm at 500 μg/mL and 250 μg/mL, respectively) against the same strain. The activities displayed by compounds 14, 16, 18, and 20 were comparable (12.33 ± 1.15 mm, 12.65 ± 0.58 mm, 12.33 ± 0.58 mm, and 12.00 ± 1.00 mm, respectively, at 500 μg/mL) to amoxicillin (13.33 ± 1.15 mm at the same concentration) against E. coli. Compound 19 showed good activity (12.00 ± 1.72 mm at 500 μg/mL) against S. aureus compared to amoxicillin (16.33 ± 0.58 mm at the same concentration). Compound 19 displayed the highest percent inhibition of DPPH with an IC50 value of 9.48 g/mL using the DPPH free radical scavenging assay compared to ascorbic acid (3.21 g/mL) and promising inhibition of peroxide formation (76.28 ± 0.12%), demonstrating its potential in preventing the formation of lipid peroxides. Thus, according to our findings, both the biological activities and in silico computational results revealed that compounds 14, 16, and 18 are good antibacterial agents against P. aeruginosa and E. coli, whereas compound 19 was found to be a promising antibacterial agent against S. aureus and an antioxidant agent. The present study revealed that the synthesized compounds appear to be lead compounds for rational drug design.

Coumarins as Fungal Metabolites with Potential Medicinal Properties

Coumarins are a structurally varied set of 2H-chromen-2-one compounds categorized also as members of the benzopyrone group of secondary metabolites. Coumarin derivatives attract interest owing to their wide practical application and the unique reactivity of fused benzene and pyrone ring systems in molecular structure. Coumarins have their own specific fingerprints as antiviral, antimicrobial, antioxidant, anti-inflammatory, antiadipogenic, cytotoxic, apoptosis, antitumor, antitubercular, and cytotoxicity agents. Natural products have played an essential role in filling the pharmaceutical pipeline for thousands of years. Biological effects of natural coumarins have laid the basis of low-toxic and highly effective drugs. Presently, more than 1300 coumarins have been identified in plants, bacteria, and fungi. Fungi as cultivated microbes have provided many of the nature-inspired syntheses of chemically diverse drugs. Endophytic fungi bioactivities attract interest, with applications in fields as diverse as cancer and neuronal injury or degeneration, microbial and parasitic infections, and others. Fungal mycelia produce several classes of bioactive molecules, including a wide group of coumarins. Of promise are further studies of conditions and products of the natural and synthetic coumarins' biotransformation by the fungal cultures, aimed at solving the urgent problem of searching for materials for biomedical engineering. The present review evaluates the fungal coumarins, their structure-related peculiarities, and their future therapeutic potential. Special emphasis has been placed on the coumarins successfully bioprospected from fungi, whereas an industry demand for the same coumarins earlier found in plants has faced hurdles. Considerable attention has also been paid to some aspects of the molecular mechanisms underlying the coumarins' biological activity. The compounds are selected and grouped according to their cytotoxic, anticancer, antibacterial, antifungal, and miscellaneous effects.

Synthetic and natural coumarins as potent anticonvulsant agents: A review with structure-activity relationship

WHAT IS KNOWN AND OBJECTIVE

The main objective of this review is to highlight the most relevant studies since 1990 (to date) in the area of medicinal chemistry aspects to provide a panoramic view to the biologists/medicinal chemists working in this area and would assist them in their efforts to design, synthesize and extract (from natural source) coumarin-based anticonvulsant agents. Also, the structure-activity relationship (SAR) studies are also discussed for further rational design of this kind of derivatives. It is hoped that this review will be helpful for new thoughts in the quest for rational designs of more active and less toxic coumarin-based antiepileptic agents.

METHODS

A literature review emphasizing the application of coumarin core as antiepileptic agents identify articles related to the topic; we performed a standardized search from 1990 to November 2021, using search engines like Scifinder, web of Science, Pubmed and Scopus.

RESULTS AND DISCUSSION

This review gives an overview of attempts to shed light and compile published reports on coumarin derivatives along with some opinions on different approaches to help the medicinal chemists in designing future generation potent yet safer anticonvulsant agents. The possible structure-activity relationships (SARs) will also be discussed to indicate the direction for the rational design of more effective candidates.

WHAT IS NEW AND CONCLUSION

The findings from this review provide new indications or directions for the discovery of new and better drugs from synthetic and naturally occurring coumarins as antiepileptic agents. In our review, we have tried to depict the recent researches which made in the design and development of novel anticonvulsant compounds with coumarin nucleus. Also, SAR of expressed derivatives indicated that the choice of a fitting substitution containing electron-withdrawing/donating groups to coumarin or with some heterocyclic moieties joined to parent coumarin skeleton assumes an essential role in changing the anticonvulsant activity of synthesized derivatives. These findings encourage the scientific community towards the optimization of the pharmacological profile of this structural moiety as an important scaffold for the treatment of epilepsy.

Recent Developments of Coumarin-based Hybrids in Drug Discovery

Coumarin scaffold is a highly significant O-heterocycle, namely benzopyran-2-ones, form an elite class of naturally occurring compounds that possess promising therapeutic perspectives. Based on its broad spectrum of biological activities, the privileged coumarin scaffold is applied to medicinal and pharmacological treatments by several rational design strategies and approaches. Structure-activity relationships of the coumarin-based hybrids with various bioactivity fragments revealed significant information toward the further development of highly potent and selective disorder therapeutic agents. The molecular docking studies between coumarins and critical therapeutic enzymes demonstrated mode of action by forming noncovalent interactions with more than one receptor, further rationally confirm information about structure-activity relationships. This review summarizes recent developments relating to coumarin-based hybrids with other pharmacophores aiming to numerous feasible therapeutic enzymatic targets to combat various therapeutic fields, including anticancer, antimicrobic, anti-Alzheimer, anti-inflammatory activities.

In vitro antimicrobial evaluation and in silico studies of coumarin derivatives tagged with pyrano-pyridine and pyrano-pyrimidine moieties as DNA gyrase inhibitors

Several coumarin-containing substitute nitrogen heterocycles have recently received considerable importance due to their diverse pharmacological properties. One-pot and rapid synthesis of coumarin derivatives was achieved via reactions of acetyl-coumarin with p-chloro-benzaldehyde and malononitrile to provide compound 2-containing cyano-amine using conventional heating. Compound 2 was condensed with different carbon electrophiles triethyl orthoformate, phenyl isocyanate, carbon disulfide, benzoyl chloride, and acetyl chloride that afforded the corresponding chromene derivatives 3-17. All the newly synthesized compounds were characterized by elemental and spectroscopic evidences. All of the synthesized compounds were tested for antimicrobial activity against S. Pneumoniae, S. Epidermidis, S. Aureus, and E. coli as Gram + ve Bacteria, K. Pneumoniae, S. Paratyphi as Gram -ve Bacteria, P. Italicum, A. Fumigatus representative for Fungi. The preliminary screening results showed that most of the compounds had moderate to high activity against all tested organisms. The most potent four compounds were subjected to further investigation against E. Coli DNA gyrase and topoisomerase IV inhibitory activity, and the results showed that all of these derivatives inhibit DNA gyrase and thus cell division. Also, in silico studies were done for the most active compounds which showed good results.