Synthesis, characterization and in vitro antimicrobial activity of novel fused pyrazolo[3,4-c]pyridazine, pyrazolo[3,4-d]pyrimidine, thieno[3,2-c]pyrazole and pyrazolo[3',4':4,5]thieno[2,3-d]pyrimidine derivatives

Antiviral Effect and Mechanism of Edaravone against Grouper Iridovirus Infection

Singapore grouper iridovirus (SGIV) is a virus with high fatality rate in the grouper culture industry. The outbreak of SGIV is often accompanied by a large number of grouper deaths, which has a great impact on the economy. Therefore, it is of great significance to find effective drugs against SGIV. It has been reported that edaravone is a broad-spectrum antiviral drug, most widely used clinically in recent years, but no report has been found exploring the effect of edaravone on SGIV infections. In this study, we evaluated the antiviral effect of edaravone against SGIV, and the anti-SGIV mechanism of edaravone was also explored. It was found that the safe concentration of edaravone on grouper spleen (GS) cells was 50 µg/mL, and it possessed antiviral activity against SGIV infection in a dose-dependent manner. Furthermore, edaravone could significantly disrupt SGIV particles and interference with SGIV binding to host cells, as well as SGIV replication in host cells. However, edaravone was not effective during the SGIV invasion into host cells. This study was the first time that it was determined that edaravone could exert antiviral effects in response to SGIV infection by directly interfering with the processes of SGIV infecting cells, aiming to provide a theoretical basis for the control of grouper virus disease.

The inhibitory effect of some pyrazole ligands and their Cu(II) complexes on the growth of Escherichia coli, Klebsiella–Enterobacter spp., and Staphylococcus aureus

The aim of this study was to evaluate the inhibitory activity of chemistry products against the growth of Escherichia coli, Klebsiella–Enterobacter spp., and Staphylococcus aureus. Pyrazole derivatives (4-bromo-2-(1H-pyrazol-3-yl)phenol, 4-nitro-3-pyrazolecarboxylic acid, N-(benzyloxycarbonyl)-1H-pyrazole-1-carboxamidine), 3-amino-5-hydroxypyrazole, 3,5-pyrazoledicarboxylic acid monohydrate, and selected complexes of Cu(II) with the mentioned pyrazoles as ligands were used as chemistry bioactives for antibacterial activity. The testing method was carried out according to the disc diffusion method. Some compounds have shown inhibitory effects against the growth of E. coli. A small number of compounds have shown inhibitory effects against the growth of Klebsiella–Enterobacter spp. but did not show inhibitory effects on Staphylococcus aureus compared to amoxicillin as a standard.

Antibacterial pyrazoles: tackling resistant bacteria

Bacterial resistance to antibiotics threatens our progress in healthcare, modern medicine, food production and ultimately life expectancy. Antibiotic resistance is a global concern, which spreads rapidly across borders and continents due to rapid travel of people, animals and goods. Derivatives of metabolically stable pyrazole nucleus are known for their wide range of pharmacological properties, including antibacterial activities. This review highlights recent reports of pyrazole derivatives targeting different bacterial strains focusing on the drug-resistant variants. Pyrazole derivatives target different metabolic pathways of both Gram-positive and Gram-negative bacteria.

A Convenient Cascade Strategy Towards the Synthesis of Novel Substituted Morpholinopyrimidines and Pyrimidooxazapines

Abstract:

A simple and novel protocol for the facile synthesis of bicyclic hybrid molecular framework of morpholinopyrimidines having six-membered pyrimidine ring fused with the morpholine unit is established. The method has been successfully employed to synthesize both regioisomers of the morpholinopyrimidine derivatives in good to high yields. The strategy is further extended successfully to synthesize bicyclic pyrimidooxazapine derivatives bearing the six-membered aromatic pyrimidine unit fused with seven-membered aliphatic oxazapine fragment.

Diverse Thiophenes as Scaffolds in Anti-cancer Drug Development: A Concise Review

Thiophenes are one of the abundantly found heterocyclic ring systems in many biologically active compounds. Moreover, various substituted thiophenes exert numerous pharmacological actions on account of their isosteric resemblance with compounds of natural origin, thus rendering them with diverse actions like antibacterial, antifungal, antiviral, anti-inflammatory, analgesic, antiallergic, hypotensives, etc. In this review, we specifically explore the chemotherapeutic potential of a variety of structures consisting of thiophene scaffolds as prospective anticancer agents.

Design, Synthesis, and Structure-Activity Relationship of Quinazolinone Derivatives as Potential Fungicides

Plant diseases caused by phytopathogenic fungi reduce the yield and quality of crops. To develop novel antifungal agents, we designed and synthesized eight series of quinazolinone derivatives and evaluated their anti-phytopathogenic fungal activity. The bioassay results revealed that compounds KZL-15, KZL-22, 5b, 6b, 6c, 8e, and 8f exhibited remarkable antifungal activity in vitro. Especially, compound 6c displayed the highest bioactivity against Sclerotinia sclerotiorum, Pellicularia sasakii, Fusarium graminearum, and Fusarium oxysporum, displaying appreciable IC₅₀ values (50% inhibitory concentration) of 2.46, 2.94, 6.03, and 11.9 μg/mL, respectively. A further mechanism interrogation revealed abnormal mycelia, damaged organelles, and changed permeability of cell membranes in S. sclerotiorum treated with compound 6c. In addition, the in vivo bioassay indicated that compound 6c possessed comparable curative and protective effects (87.3 and 90.7%, respectively) to the positive control azoxystrobin (89.5 and 91.2%, respectively) at 100 μg/mL concentration against S. sclerotiorum. This work validated the potential of compound 6c as a new and promising fungicide candidate, contributing to the exploration of potent antifungal agents.

Inhibition of Glioma Cell Growth and Apoptosis Induction through Targeting Wnt10B Expression by Pyrazolo[4,3-c]pyridine-4-one

Background

Gliomas are commonly diagnosed tumors in the central nervous system that have an elevated mortality rate. The present study evaluated pyrazolo[4,3-c]pyridine-4-one (PP-4-one) as an anti-proliferative agent against glioma cells and investigated the associated mechanism.

Material/Methods

The changes in cell growth were analyzed by Cell Counting Kit-8 (CCK-8) and apoptosis by flow cytometry using Annexin V-FITC staining kit. The FACSCalibur flow cytometer was used for analysis of DNA content and western blotting for protein expression.

Results

The PP-4-one treatment suppressed viability of U251, C6, and U87 cells significantly at a concentration of 0.25 μM. At a concentration of 16 μM, PP-4-one treatment for 72 hours suppressed viability of U251, C6, and U87 cells to 24%, 21%, and 20%, respectively. Treatment with PP-4-one suppressed cyclic 3′,5′-adenosine monophosphate (cAMP) levels in U251 and C6 cells significantly (P<0.05) depending on the concentration. The apoptotic cells were increased significantly (P<0.05) by PP-4-one treatment in U251 and C6 cell cultures. A considerable enhancement in the proportion of U251 and C6 cells in the G0/G1 phase was recorded on incubation with PP-4-one. Treatment of U251 and C6 cells with PP-4-one markedly enhanced p21 expression relative to the control. The B-cell lymphoma (Bcl-2) level in PP-4-one treated U251 and C6 cells was markedly lower relative to the control cells. The Bax, caspase-3, and caspase-9 levels were elevated markedly by PP-4-one treatment in U251 and C6 cells.

Conclusions

This study demonstrated that PP-4-one has anti-proliferative potential for glioma cells via targeting cAMP and Bcl-2 levels. It also promoted glioma cell apoptosis through caspase activation and arrest of the cell cycle. Thus, PP-4-one may be used to develop drug candidates for the glioma treatment.

Efficacy of Novel Pyrazolone Phosphodiesterase Inhibitors in Experimental Mouse Models of Trypanosoma cruzi

Pyrazolones are heterocyclic compounds with interesting biological properties. Some derivatives inhibit phosphodiesterases (PDEs) and thereby increase the cellular concentration of cyclic AMP (cAMP), which plays a vital role in the control of metabolism in eukaryotic cells, including the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease (CD), a major neglected tropical disease. In vitro phenotypic screening identified a 4-bromophenyl-dihydropyrazole dimer as an anti-T. cruzi hit and 17 novel pyrazolone analogues with variations on the phenyl ring were investigated in a panel of phenotypic laboratory models. Potent activity against the intracellular forms (Tulahuen and Y strains) was obtained with 50% effective concentration (EC50) values within the 0.17 to 3.3 μM range. Although most were not active against bloodstream trypomastigotes, an altered morphology and loss of infectivity were observed. Pretreatment of the mammalian host cells with pyrazolones did not interfere with infection and proliferation, showing that the drug activity was not the result of changes to host cell metabolism. The pyrazolone NPD-227 increased the intracellular cAMP levels and was able to sterilize T. cruzi-infected cell cultures. Thus, due to its high potency and selectivity in vitro, and its additive interaction with benznidazole (Bz), NPD-227 was next assessed in the acute mouse model. Oral dosing for 5 days of NPD-227 at 10 mg/kg + Bz at 10 mg/kg not only reduced parasitemia (>87%) but also protected against mortality (>83% survival), hence demonstrating superiority to the monotherapy schemes. These data support these pyrazolone molecules as potential novel therapeutic alternatives for Chagas disease.

Synthesis of Some New 1, 3, 4-Oxadiazole, Pyrazole, and Pyrimidine Bearing Thienopyrazole Moieties

AIM AND OBJECTIVE

According to the literature survey, pyrazole is a unique template that is associated with several biological activities. This article highlighted the research work of many researchers reported in the literature for synthesis and different pharmacological activities of the pyrazole nucleus. In the present work, pyrazol- 3-one 1 was reacted with cyanoacetic acid hydrazide and elemental sulfur to afford the corresponding thieno[3,2-c]pyrazol-6-carbohydrazide 3 derivatives. The latter compound reacted with some electrophilic reagents such as DMF-DMA, triethylorthoformate, arylidenemalononitriles and chalcones under neat conditions to give substituted oxadiazole and pyrazole, respectively. The treatment of compound 3 with active methylene reagents such as acetylacetone, diethylmalonate, ethyl acetoacetate and ethyl cyanoacetate under suitable conditions afforded pyrazole derivatives 10, 11, 13, and 15, respectively. Novel pyrazolothienopyrimidine 27 and 30 were prepared from precursor 26 with carbon disulfide and triethylorthoformate, respectively. The chemical structures of the newly synthesized compounds were established by elemental and spectral analyses including IR, and 1HNMR in addition to 13C-NMR and mass spectra.

MATERIALS AND METHODS

A novel substituted pyrazole, pyrimidine and pyrazolothienopyrimidine were obtained via Gewald synthesis of thiophene and fused thiophene and Mannich reactions of 5-amino-3-phenyl-1Hthieno[ 3,2-c]pyrazole-6-carbohydrazide.

RESULTS AND DISCUSSION

A series of some newly azoles and azines were prepared via reaction of thieno[3,2- c]pyrazol-6-carbohydrazide derivative 3 as starting material with some electrophilic and nucleophilic reagents. The structures of target compounds were established by elemental analyses and spectral data.

CONCLUSION

Pyrazole is a unique template that is associated with several biological activities. This article highlighted the research work of many researchers reported in the literature for synthesis and different pharmacological activities of the pyrazole nucleus. In the current investigation, we have developed new and efficient methods for the synthesis of thieno[3,2-c]pyrazol-6-carbohydrazide derivatives. In addition, we have explored the preparative potential of these substances as intermediates for the synthesis of substituted pyrazoles and fused pyrazoles 10-30, respectively.

Pyrazolone structural motif in medicinal chemistry: Retrospect and prospect

The pyrazolone structural motif is a critical element of drugs aimed at different biological end-points. Medicinal chemistry researches have synthesized drug-like pyrazolone candidates with several medicinal features including antimicrobial, antitumor, CNS (central nervous system) effect, anti-inflammatory activities and so on. Meanwhile, SAR (Structure-Activity Relationship) investigations have drawn attentions among medicinal chemists, along with a plenty of analogues have been derived for multiple targets. In this review, we comprehensively summarize the biological activity and SAR for pyrazolone analogues, wishing to give an overall retrospect and prospect on the pyrazolone derivatives.

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The pyrazolone structural motif is a critical element of drugs aimed at different biological end-points.

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The pyrazolone analogues have been carried out to drug-like candidates with broad range of medicinal properties.

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This review wishes to give an overall retrospect and prospect on the pyrazolone derivatives.

Therapeutic importance of synthetic thiophene

Thiophene and its substituted derivatives are very important class of heterocyclic compounds which shows interesting applications in the field of medicinal chemistry. It has made an indispensable anchor for medicinal chemists to produce combinatorial library and carry out exhaustive efforts in the search of lead molecules. It has been reported to possess a wide range of therapeutic properties with diverse applications in medicinal chemistry and material science, attracting great interest in industry as well as academia. It has been proven to be effectual drugs in present respective disease scenario. They are remarkably effective compounds both with respect to their biological and physiological functions such as anti-inflammatory, anti-psychotic, anti-arrhythmic, anti-anxiety, anti-fungal, antioxidant, estrogen receptor modulating, anti-mitotic, anti-microbial, kinases inhibiting and anti-cancer. Thus the synthesis and characterization of novel thiophene moieties with wider therapeutic activity is a topic of interest for the medicinal chemist to synthesize and investigate new structural prototypes with more effective pharmacological activity. However, several commercially available drugs such as Tipepidine, Tiquizium Bromides, Timepidium Bromide, Dorzolamide, Tioconazole, Citizolam, Sertaconazole Nitrate and Benocyclidine also contain thiophene nucleus. Therefore, it seems to be a requirement to collect recent information in order to understand the current status of the thiophene nucleus in medicinal chemistry research.

Design and synthesis of novel 2-(6-thioxo-1,3,5-thiadiazinan-3-yl)-N'-phenylacethydrazide derivatives as potential fungicides

A series of novel 2-(6-thioxo-1,3,5-thiadiazinan-3-yl)-N'-phenylacethydrazide derivatives were designed, synthesized and evaluated for their antifungal activities against Fusarium graminearum (Fg), Rhizoctonia solani (Rs), Botrytis cinerea (Bc) and Colletotrichum capsici (Cc). The bioassay results in vitro showed that most of the title compounds exhibited impressive antifungal activities against the above plant fungi. Particularly, the compounds 5c, 5f, 5g, 5i, 5m and 5p displayed desirable anti-Rs activities, with the corresponding EC₅₀ values of 0.37, 0.32, 0.49, 0.50, 0.46 and 0.45 µg/mL, respectively, which are superior to the positive control carbendazim (0.55 µg/mL). Further in vivo bioassay results showed that the anti-Rs activity of title compound 5f at 200 µg/mL reached 95.84% on detached rice leaves and 93.96% on rice plants. Featuring convenient synthesis, novel structures and desirable antifungal activity, these 2-(6-thioxo-1,3,5-thiadiazinan-3-yl)-N'-phenylacethydrazide derivatives could be further studied as the potential candidates of novel agricultural fungicides.