Synthesis and in vitro antimicrobial activities of new (cyano-NNO-azoxy)pyrazole derivatives

Regioselective synthesis of novel nitroso-pyrazolylquinoxalines via HOAc-mediated cyclocondensation of 2-hydroxyimino-1,3-diketones with hydrazinylquinoxalines

This article describes the regioselective synthesis of novel nitroso-pyrazolylquinoxalines via cyclocondensation of 2-hydroxyimino-1,3-diketones with hydrazinylquinoxalines. Of note, this is the first time that 2-hydroxyimino-1,3-diketones are used as electrophilic reagents to cyclocondensation with hetarylhydrazines. The cyclocondensation proceeded through a hydrazone intermediates formation. A series of novel nitroso-substituted pyrazolylquinoxalines were synthesized by both "one-pot" and "two-step" procedures in up to 86% yields. Importantly, a gram-scale synthesis of nitroso-pyrazolylquinoxalines, their oxidation and reduction were successfully accomplished.

Synthesis, Characterization, Pharmacogenomics, and Molecular Simulation of Pyridinium Type of Ionic Liquids and Their Applications

Substituted pyridinium bromides are prepared by conventional and solvent-free greener methods. The solvent-free solid-phase (greener) method is superior to the conventional method because of its nontoxic nature, simple reaction setup procedure, and twenty times less time consumption. Column chromatography and toxic organic solvents are avoided. Substituted pyridinium salts 1-2(a-c) show excellent catalytic response in the preparation of β-amino carbonyl derivatives using the conventional approach. Pharmacokinetics is very important in target validation and in shifting a lead compound into a drug. The physicochemical properties discussed here can be used effectively in the drug designing candidate, which is a cumbersome process in clinical research. In addition, molecular simulations are demonstrated, and compounds 1-2(a-c) possess the most potent VEGFR-2 kinase protein inhibitory activities, and most interestingly, compound 2a strongly binds and regulates the VEGFR-2 kinase activity in therapeutic approaches and cancer prevention.

A Molecular Insight into Pyrazole Congeners as Antimicrobial, Anticancer, and Antimalarial Agents

BACKGROUND

Pyrazole is a bioactive heterocyclic congener found in a wide range of biological and pharmacological applications. Due to their multiple prospective uses, developing innovative pyrazoles and analogues, disclosing revolutionary ways for synthesizing this nucleus, investigating diverse potencies of that heterocycle, and seeking for possible applications of pyrazoles are all growing more significant Objectives: Pyrazole scaffolds have been proven to be successful as antimicrobial, anticancer, antimalarial therapeutic against multiple targets like DNA gyrase, topoisomerase IV, Hsp90, and several kinase enzymes. Its moiety has absorbed the attention of many scientists to research chemical and pharmacological profile due to this miscellany in the biotic region.

RESULTS

The review covers pyrazole scaffolds with a variety of biological functions, as well as attempts to connect the structure-activity relationship. Multiple pyrazole analogues have been produced as lead compounds, and their activities have been evaluated.

CONCLUSION

The combination of pyrazole with other pharmacophores in a molecule might lead to novel potent therapeutic medicines, which could aid in the development of potent lead compounds.

Biological Insights of Fluoroaryl-2,2'-Bichalcophene Compounds on Multi-Drug Resistant Staphylococcus aureus

Resistance of bacteria to multiple antibiotics is a significant health problem; hence, to continually respond to this challenge, different antibacterial agents must be constantly discovered. In this work, fluoroaryl-2,2'-bichalcophene derivatives were chemically synthesized and their biological activities were evaluated against Staphylococcus aureus (S. aureus). The impact of the investigated bichalcophene derivatives was studied on the ultrastructural level via scanning electron microscopy (SEM), molecular level via sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) method and on the biofilm inhibition via the electrochemical biosensors. Arylbichalcophenes' antibacterial activity against S. aureus was affected by the presence and location of fluorine atoms. The fluorobithiophene derivative MA-1156 displayed the best minimum inhibitory concentration (MIC) value of 16 µM among the tested fluoroarylbichalcophenes. Over a period of seven days, S. aureus did not develop any resistance against the tested fluoroarylbichalcophenes at higher concentrations. The impact of fluoroarylbichalcophenes was strong on S. aureus protein pattern showing high degrees of polymorphism. SEM micrographs of S. aureus cells treated with fluoroarylbichalcophenes displayed smaller cell-sizes, fewer numbers, arranged in a linear form and some of them were damaged when compared to the untreated cells. The bioelectrochemical measurements demonstrated the strong sensitivity of S. aureus cells to the tested fluoroarylbichalcophenes and an antibiofilm agent. Eventually, these fluoroarylbichalcophene compounds especially the MA-1156 could be recommended as effective antibacterial agents.

Pyrazole-based analogs as potential antibacterial agents against methicillin-resistance staphylococcus aureus (MRSA) and its SAR elucidation

Methicillin-resistant Staphylococcus aureus (MRSA) is becoming lethal to humanity due to easy transmission and difficult-to-treat skin and flimsy diseases. The most threatening aspect is the rapid resistance development of MRSA to any approved antibiotics, including vancomycin. The development of new, efficient, and nontoxic drug candidate to fight against MRSA isolates is the need of the hour. The intriguing molecular structure and versatile bioactive pyrazole core attracting to development required novel antibiotics. This review presents the decade developments of pyrazole-containing derivatives with a broad antibacterial movement against diverged bacterial strains. In specific, we correlated the efficacy of structurally diversified pyrazole analogs against MRSA and discussed different angles of structure-activity relationship (SAR). The current survey highlights pyrazole hybrids' present scenario on MRSA studies, covering articles published from 2011 to 2020. This collective information may become an excellent platform to plan and develop new pyrazole-based small MRSA growth inhibitors with minimal side effects.

Current Research on Antiepileptic Compounds

Epilepsy affects about 1% of the world’s population. Due to the fact all antiepileptic drugs (AEDs) have some undesirable side effects and about 30% of epileptic patients are not seizure-free with the existing AEDs, there is still an urgent need for the development of more effective and safer AEDs. Based on our research work on antiepileptic compounds and other references in recent years, this review covers the reported work on antiepileptic compounds which are classified according to their structures. This review summarized 244 significant anticonvulsant compounds which are classified by functional groups according to the animal model data, although there are some limitations in the data. This review highlights the properties of new compounds endowed with promising antiepileptic properties, which may be proven to be more effective and selective, and possibly free of unwanted side effects. The reviewed compounds represent an interesting possibility to overcome refractory seizures and to reduce the percentage of patients with a poor response to drug therapy.

Anticancer, antioxidant activities, and DNA affinity of novel monocationic bithiophenes and analogues

A series of 15 monocationic bithiophenes and isosteres were prepared and subjected to in vitro antiproliferative screening using the full National Cancer Institute (NCI)-60 cell line panel, representing nine types of cancer. Among the nine types of cancer involved in a five-dose screen, non-small cell lung and breast cancer cell lines were the most responsive to the antiproliferative effect of the tested compounds, especially cell lines A549/ATCC, NCI-H322M, and NCI-H460, whereas compounds 1a, 1c, 1d, and 7 exhibited potent activity, with GI50 values (drug concentration that causes 50% inhibition of cell growth) from less than 10 nM to 102 nM. In addition, compounds 1c and 1d gave GI50 values of 73 nM and 79 nM, respectively, against the MDA-MB-468 breast cancer cell line. Structure-activity relationship findings indicated that the mononitriles were far less active than their corresponding monoamidines and, within the amidines series, the bioisosteric replacement of a thiophene ring by a furan led to a reduction in antiproliferative activity. Also, molecular manipulations, involving substitution on the phenyl ring, or its replacement by a pyridyl, or alteration of the position of the amidine group, led to significant alteration in antiproliferative activity. On the other hand, DNA studies demonstrated that these monoamidine bichalcophenes have promising ability to cleave the genomic DNA. These monoamidines show a wide range of DNA affinities, as judged from their DNA cleavage effect, which are remarkably sensitive to all kinds of structural modifications. Finally, the novel bichalcophenes were tested for their antioxidant property by the ABTS (2,2'-azino- bis(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt) assay, as well as lipid and nitric oxide scavenging techniques, and were found to exhibit good-to-potent antioxidant abilities.

Molecular docking of 1H-pyrazole derivatives to receptor tyrosine kinase and protein kinase for screening potential inhibitors

Tyrosine kinase receptor and protein kinases drawn much attention for the scientific fraternity in drug discovery due to its important role in different cancer, cardiovascular diseases and other hyper-proliferative disorders. Docking studies of pyrazole derivatives with tyrosine kinase and different serine/threonine protein kinases were employed by using flexible ligand docking approach of AutoDock 4.2. Among the molecules tested for docking study, 2-(4-chlorophenyl)-5-(3-(4-chlorophenyl)-5-methyl-1- phenyl-1H-pyrazol-4-yl)-1,3,4-thiadiazole (1b), 2-(4-methoxyphenyl)-5-(3-(4-methoxyphenyl)-5-methyl-1-phenyl-1H-pyrazol-4-yl)- 1,3,4-thiadiazole (1d) and 2-(4-chlorophenyl)-5-(3-(4-chlorophenyl)-5-methyl-1-phenyl-1H-pyrazol-4-yl)-1,3,4-thiadiazole (2b) revealed minimum binding energy of -10.09, -8.57 and -10.35 kJ/mol with VEGFR-2 (2QU5), Aurora A (2W1G) and CDK2 (2VTO) protein targets, respectively. These proteins are representatives of plausible models of interactions with different anticancer agents. All the ligands were docked deeply within the binding pocket region of all the three proteins, showing reasonable hydrogen bonds. The docking study results showed that these pyrazole derivatives are potential inhibitor of all the three protein targets; and also all these docked compounds have good inhibition constant, vdW + Hbond + desolv energy with best RMSD value.

Evaluation of the biological activity of novel monocationic fluoroaryl-2,2'-bichalcophenes and their analogues

A series of bichalcophene fluorobenzamidines 5a–e was synthesized from the corresponding mononitriles 4a–e via a direct reaction with lithium bis(trimethylsilyl)amide LiN(TMS)₂ followed by de-protection with ethanolic HCl (gas). Bichalcophene fluorobenzonitriles 4a–e were prepared adopting a Stille coupling reaction between the bromo compounds 3a–c and 2-(tri-n-butylstannyl)furan or analogues. As an approach to drug discovery, the structure–antimutagenicity relationship of novel fluoroarylbichalcophenes was examined using the Ames Salmonella/microsomal assay. At nontoxic concentrations (10 and 20 μM), all derivatives alone or in combination with sodium azide (NaN₃; 2 μg/plate) or benzo[a]pyrene (B[a]P; 20 μM) in the presence of S9 mix were not mutagenic. The fluoroaryl derivatives significantly reduced the NaN₃-induced and B[a]P-induced mutagenicity under pre-exposure and co-exposure conditions. The recorded antimutagenic activity of fluoroaryl derivatives varied depending on the kind of mutagen and the exposure regimen. Monocationic fluoroarylbichalcophenes were superior to the corresponding mononitriles in reducing B[a]P-induced mutagenicity. Nevertheless, mononitriles were more active against NaN₃, especially at low concentrations and under pre-exposure treatments. The antimutagenic activity was congruent with a high antioxidant activity that could promote the DNA repair system. The fluorine substitution changed the antimutagenic signature of bichalcophenes. Some of these compounds could be selected for further anticancer studies.

Isolation and characterization of unusual hydrazides from Streptomyces sp. impact of the cultivation support and extraction procedure

Three novel hydrazides, geralcins C-E (1-3), were isolated from Streptomyces sp. LMA-545, together with MH-031 and geralcins A and B. This unusual family of compounds was isolated from liquid-state and agar-supported fermentation using Amberlite XAD-16 solid-phase extraction during the cultivation step. The use of such neutral resin during the cultivation step allowed the specific adsorption of microbial secondary metabolites, avoiding any contamination of the crude extracts by the constituents of the culture medium. The trapped compounds were eluted from the resin with methanol, and their structures elucidated using (1)H, (13)C, and (15)N NMR spectroscopic analysis and high-resolution mass spectrometry. Molecular modeling calculations were applied in order to support structural attributions. No antimicrobial, cytotoxic, or DnaG-inhibition activities were detected for geralcins D and E. Geralcin C has no antimicrobial activity but exhibited an IC(50) of 0.8 μM against KB and HCT116 cancer cell lines. Furthermore, geralcin C inhibited the E. coli DnaG primase, a Gram-negative antimicrobial target, with an IC(50) of 0.7 mM.

(E)-N'-Hy-droxy-1,3-diphenyl-4,5-di-hydro-1H-pyrazole-5-carboximidamide

In the mol-ecule of the title compound, C(16)H(16)N(4)O, the pyrazole ring makes dihedral angles of 8.52 (13) and 9.26 (12)° with the phenyl rings. The dihedral angle between the benzene rings is 1.86 (13)°. In the crystal, mol-ecules are linked into centrosymmetric dimers via pairs of O-H⋯N hydrogen bonds. Weak N-H⋯N inter-actions connect the dimers into a chain along the [100] direction. The pyrazole ring adopts a highly flattened envelope conformation.