Synthesis and antibacterial activity of novel 1,3-diphenyl-1H-pyrazoles functionalized with phenylalanine-derived rhodanines

Fluorinated azoles as effective weapons in fight against methicillin-resistance staphylococcus aureus (MRSA) and its SAR studies

The rapid spread of Methicillin-resistant Staphylococcus aureus (MRSA) and its difficult-to-treat skin and filmsy diseases are making MRSA a threat to human life. The most dangerous feature is the fast emergence of MRSA resistance to all recognized antibiotics, including vancomycin. The creation of novel, effective, and non-toxic drug candidates to combat MRSA isolates is urgently required. Fluorine containing small molecules have taken a centre stage in the field of drug development. Over the last 50 years, there have been a growing number of fluorinated compounds that have been approved since the clinical usage of fluorinated corticosteroids in the 1950 s and fluoroquinolones in the 1980 s. Due to its advantages in terms of potency and ADME (absorption, distribution, metabolism, and excretion), fluoro-pharmaceuticals have been regarded as a potent and useful tool in the rational drug design method. The flexible bioactive fluorinated azoles are ideal candidates for the development of new antibiotics. This review summarizes the decade developments of fluorinated azole derivatives with a wide antibacterial activity against diverged MRSA strains. In specific, we correlated the efficacy of structurally varied fluorinated azole analogues including thiazole, benzimidazole, oxadiazole and pyrazole against MRSA and discussed different angles of structure-activity relationship (SAR).

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.

Synthesis and In vitro Antibacterial, Antitubercular Studies of Novel Fluoroquinolones Analogs Containing 4-substituted Sec Amine

Background:

Tuberculosis is a contagious, air borne disease and second leading cause of death among infectious diseases worldwide. Fluoroquinolones are well-known antibacterial agents and they were recommended as second-line of antitubercular drugs.

Method:

A series of novel fluoroquinolone analogs 6-24 was effectively synthesized. An attempt was made by tagging the substituted pyrazole on to fluoroquinolones for the first time at C-7 position. The newly synthesized compounds were characterized by FTIR, 1HNMR, ESI-MS, HR-MS and elemental analysis. The in vitro antibacterial activity of all the title compounds was investigated against various gram positive, gram negative bacterial organisms and in vitro antitubercular activity against Mycobacterium Tuberculosis H37Rv strain.

Result:

Most of the synthesized compounds showed comparable activity against the entire gram positive and gram negative bacterial organisms. Fluoroquinolone 16 showed enhanced activity against both type of bacterial strains and compound 11showed promising activity against MTB-H37Rv strain.

Conclusion:

Some of the novel fluoroquinolone analogs (11, 16) showed potent antibacterial, antitubercular activity.

Drug screening of rhodanine derivatives for antibacterial activity

Introduction: Bacteriological infections are a major risk to human health. These include all hospital and public-acquired infections. In drug discovery, rhodanines are privileged heterocyclic frameworks. Their derivatives possess strong anti-bacterial activity and some of them have shown potent activity against multidrug-resistant pathogens, both under in vitro and in vivo conditions. To treat multi-drug resistant pathogens, the development of novel potent drugs, with superior anti-bacterial efficacy, is paramount. One avenue which shows promise is the design and development of novel rhodanines.Areas covered: This review summarizes the status on rhodanine-based derivatives and their anti-bacterial activity, based on published research over the past six years. Furthermore, to facilitate the design of novel derivatives with improved functions, their structure-activity relationships are assessed with reference to their efficacy as anti-bacterial agents and their toxicity.Expert opinion: The pharmacological activity of molecules bearing a rhodanine scaffold needs to be very critically assessed in spite of considerable information available from various biological evaluations. Although, some data on structure-activity relationship frameworks is available, information is not adequate to optimize the efficacy of rhodanine derivatives for different applications.

Synthesis and biological evaluation of tryptophan-derived rhodanine derivatives as PTP1B inhibitors and anti-bacterial agents

Several series of novel tryptophan-derived rhodanine derivatives were synthesized and identified as potential competitive PTP1B inhibitors and antibacterial agents. Among the compounds studied, 10b was found to have the best in vitro inhibition activity against PTP1B (IC₅₀ = 0.36 ± 0.02 μM). In addition, the compounds also showed potent inhibition against other PTPs, especially CDC25B. Molecular docking analysis demonstrated that compounds 7c and 10b could occupy both the catalytic site and the adjacent pTyr binding site simultaneously. The compounds also showed higher levels of activity against gram-positive strains, the gram-negative strain Escherichia coli 1924, and multidrug-resistant gram-positive bacterial strains. Compounds 7c, 8c, 9e, 10a, and 10c had comparable or more potent antibacterial activity than the positive controls.

Synthesis of novel dihydrotriazine derivatives bearing 1,3-diaryl pyrazole moieties as potential antibacterial agents

Three novel series of dihydrotriazine derivatives bearing 1,3-diaryl pyrazole moieties were designed, synthesized and evaluated in terms of their antibacterial and antifungal activities. Most of the synthesized compounds showed potent inhibition of several Gram-positive bacterial strains (including multidrug-resistant clinical isolates) and Gram-negative bacterial strains with minimum inhibitory concentration values in the range of 1-64 µg/mL. Compounds 4b and 4c presented the most potent inhibitory activity against Gram-positive bacteria (S. aureus 4220, MRSA 3167, QRSA 3519) and Gram-negative bacteria (E. coli 1924), with minimum inhibitory concentration values of 1 or 2 µg/mL. Compared with previous studies, these compounds exhibited a broad spectrum of inhibitory activity. The cytotoxic activity of the compounds 4a, 4b, 4c and 11n were assessed in L02 cells. In vitro enzyme study implied that compound 4c exerted its antibacterial activity through DHFR inhibition.

Recent Highlights on the Synthesis of Pyrazoles with Antimicrobial Activity

Background:

Heterocyclic compounds containing nitrogen atoms such as pyrazoles have a long history and applicability in the field of medicinal chemistry. Many compounds containing pyrazole moiety have been reported in the available literature for their prominent biological activities, including antimicrobial activity against different microorganisms. Over the years, there has been a concern with the many health problems associated with the dramatic increase of microbial infections and resistance to standard drugs, so there is a need for the development of more effective antimicrobial agents. Pyrazoles and their derivatives are promising candidates to bypass these problems with good safety profiles, and there is a wide range of synthetic methodologies for their obtainment. This review aims to compact a literature survey (2012-2017) very informative and helpful for researchers who wish to study or continue the development of new, potent and broad-spectrum antimicrobial compounds.

Methods:

This review encompasses reports on the synthesis and antimicrobial evaluation of synthetic pyrazoles from the year 2012 to 2017, which were extracted from bibliographic databases such as PubMed, scielo, sciencedirect, scifinder, and scopus. The main keywords in our search were “pyrazole” and “antimicrobial activity”, in which we made efforts to include synthetic and biological methodologies that can be useful for laboratories of different levels of infrastructure. Moreover, inclusion/ exclusion criteria was applied to select quality reports which could demonstrate different tools of antimicrobial evaluation, focusing on the advances made in the area, such as evaluation in silico and exploration of the possible mechanism of action for active compounds.

Results:

Thirty-four papers were included in this work, which was displayed chronologically from the year 2012 to 2017 in order to enhance the advances made in the area, with at least five reports from each year. We found that the most commonly tested bacterial strains are Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and from the year 2016 onwards Mycobacterium tuberculosis. The most common tested fungal strains are Candida albicans, Aspergillus flavus, and Aspergillus niger. The majority of articles expressed the antimicrobial results as a zone of inhibition, leading to the determination of the Minimum Inhibitory Concentration (MIC) and a probable mechanism of action for the most prominent compounds, considering cytotoxicity. Aromatic aldehydes and ketones are key reactants to obtain important precursors for the synthesis of pyrazoles, such as chalcones, together with alkyl or phenylhydrazines and thiosemicarbazide. A great variation in the reported MICs was found as there is no standard maximum limit, but many compounds exhibited antimicrobial activity comparable or better than standard drugs, from which 10 reports active compounds with MIC lower than 5 μg mL-1.

Conclusion:

The findings of this work support the importance of pyrazole moiety in the structure of antimicrobial compounds and the versatility of synthetic methodologies to obtain the target products. Results clearly indicate that they are attractive target compounds for new antimicrobial drugs development. We hope that this information will guide further studies on continuing the search for more effective, highly active antimicrobial agents.

Synthesis and in Vitro Anti-Tumor Activity of A New Class of Acyclic Thioglycosides

The reaction of sodium 2-cyano-ethylene-1-thiolate salts with 2,3,4,6-tetra-O-acetyl-D-gluco- and D-galactopyranosyl bromides and with 2,3,4-tri-O-acetyl-D-xylo-. and L-arabinopyranosyl bromides, respectively, afforded new thioglycosides. Heating of the resultout glycosides with hydrazine produced pyrazole derivatives. The cytotoxicities toward the hepatoma cell line (HEPG2) of some synthesized compounds were tested. Some compounds showed high cytotoxic activity against (HEPG2) cell line. The OH moieties in the free glycosides were vital for potency. The synthesis procedures, spectroscopic data and antitumor activities for the prepared compounds are reported herein.

Synthetic approaches, structure activity relationship and biological applications for pharmacologically attractive pyrazole/pyrazoline-thiazolidine-based hybrids

The features of the chemistry of 4-thiazolidinone and pyrazole/pyrazolines as pharmacologically attractive scaffolds were described in a number of reviews in which the main approaches to the synthesis of mentioned heterocycles and their biological activity were analyzed. However, the pyrazole/pyrazoline–thiazolidine-based hybrids as biologically active compounds is poorly discussed in the context of pharmacophore hybrid approach. Therefore, the purpose of this review is to summarize the data about the synthesis and modification of heterocyclic systems with thiazolidine and pyrazoline or pyrazole fragments in molecules as promising objects of modern bioorganic and medicinal chemistry. The description of biological activity was focused on SAR analysis and mechanistic insights of mentioned hybrids.

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Synthesis and chemistry of pyrazole/pyrazoline–thiazolidine-based hybrids.

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A diverse spectrum of pyrazole/pyrazoline–thiazolidine-based hybrids biological activities has been presented.

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Structure activity relationship of pyrazole/pyrazoline–thiazolidine-based hybrids for different activities has been discussed.