Synthesis and characterization of novel benzimidazole embedded 1,3,5-trisubstituted pyrazolines as antimicrobial agents (original) (raw)
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The Series of N-(5-(Substituted phenyl)-4,5-dihydro-1H-pyrazol-3-yl)-4H-1,2,4-triazol-4-amine compounds were prepared by reaction of 4-amino-1,2,4-Triazole with Acetyl Chloride followed by different aromatic aldehydes and cyclization with hydrazine hydrate. The structures of new compounds were confirmed by IR and1H-NMR spectral data. Anti-bacterial and Anti-fungal activities were evaluated and compared with the standard drugs, some compounds of the series exhibited promising anti-microbial and anti-fungal activity compared to standard drugs.
Journal of Heterocyclic Chemistry, 2011
A series of new substituted azo-pyrazolinecompounds have been synthesized and evaluated for their in vitro antimicrobial activity along with standard ciprofloxacin against gram positive Staphylococcus aureus and gram negative Klebsiellapneumoniae. The preparation of the newly azo-pyrazolinecompounds have been started by the direct diazotization of p-aminoacetophenone with o-cresol as an active coupling agent. The prepared azoacetophenone(1) was benzylated with p-chlorobenzylchloride to give benzyloxy-azochalcones (2). The later compound was reacted with a series of substituted benzaldehydesgiving a new chalcones(3a-j), which were cyclized to new pyrazolines(4a-j) by the treatment with phenylhydrazin. Finally the structures of the synthesized compounds were confirmed spectroscopically using FT-IR, 1 H-NMR, 13 C-NMR and 13 C-DEPT-135 spectra.
Al-Mustansiriyah Journal of Science, 2021
A new series of pyrazoline derivatives (3-10) have been synthesized and characterized on the basis of FT-IR, 1H-NMR, and Mass techniques. 1-(4-Aminophenyl)-3-(pyridin-4-yl)prop-2-en-1-one (1) as a starting material was prepared by the reaction of 4-aminoacetophenone and 4-pyridinecarboxaldehyde in ethanol, using sodium hydroxide as a catalyst. Pyrazoline derivatives 2 was obtained via the cyclization reaction of compound 1 by the action of hydrazine hydrate 80% in ethanol. The target derivatives (3-8) were obtained by the reaction of pyrazoline derivative (2) with the corresponding aldehyde in ethanol. The novel pyrazoline derivatives 9 and 10 were synthesized by the reaction of pyrazoline derivative 2 with the corresponding anhydride (maleic or phthalic anhydride) in presence of anhydrous sodium acetate in glacial acetic acid. The synthesized derivatives were screened against several bacterial strains: Staphylococcus aureus, Staphylococcus espidermididis, Escherichia coli, Klebsiel...
Synthesis and Antimicrobial Activities of Some Benzimidazolyl Pyrazoles
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The reaction of benzimidazolyl chalcone (1) with bromine in Chloroform gave corresponding dibromo chalcones (2) which underwent condensation with hydrazine hydrate to afford the title compounds 3- benzimidazolyl -5-aryl-2pyrazole (3). Newly prepared pyrazoles were screened for their antimicrobial activity in vitro, some of has exhibited promising activity.
Synthesis and Antimicrobial Evaluation of Some New Pyrazoline Derivatives
Indian Journal of Applied Research, 2011
A series of 5-o xohexannitrile derivatives IIa-d was prepared by react ion of acry lonitrile with ketones Ia-d. On the other hand, semicarbazone derivatives IVa-d were obtained upon reaction of IIa-d with semicarbazide. Hydrolysis and esterification in one step reaction of δ-ketonitrile IIa-d resulted in the formation of the corresponding δ-ketoesters Va-d. The δ-ketoesters Va-d is readily cyclized to the corresponding cyclohexan-1,3-diones VIa-d when heated with alcoholic sodium metho xide. Moreover, coupling o f VIa, VIb and VId with aryl diazoniu m chlo ride afforded the corresponding 2-(ary l diazenyl) derivatives VIIa-f, respectively. Furthermo re, bis-(2,6-diketo-3-phenylcyclohexyl)methane VIII was synthesized by condensing VIa with benzaldehyde. Bro mination of VId in d ilute acetic acid afforded the corresponding bromo derivative IX. Heating of cyclohexanone-2-methyl propionate in alcoholic sodium metho xide affo rded bicycle[1,3,3]nonan-2,9-dione X. These compounds were characterized by analytical and spectral analyses and screened for their antibacterial activity against Gram-possitive bacteria and Gram-negative bacteria. The synthesized compounds (VIIa-f)-X showed significant antibacterial activ ity against P. Aeruginosa (MIC 0.30-0.45 μg/ mL), S. Aureus (MIC 0.25-0.45 μg/ mL) and B. Subtilis (MIC 0.20-0.45 μg/ mL) and exh ibited moderate antibacterial activ ity against E. Coli (M IC 0.30-0.45 μg/ mL) co mpared with the standard drug Ciproflo xacin.
Synthesis of Antimicrobial Benzimidazole–Pyrazole Compounds and Their Biological Activities
Antibiotics, 2021
The synthesis of new compounds with antimicrobial and antiviral properties is a central objective today in the context of the COVID-19 pandemic. Benzimidazole and pyrazole compounds have remarkable biological properties, such as antimicrobial, antiviral, antitumor, analgesic, anti-inflammatory, anti-Alzheimer’s, antiulcer, antidiabetic. Moreover, recent literature mentions the syntheses and antimicrobial properties of some benzimidazole–pyrazole hybrids, as well as other biological properties thereof. In this review, we aim to review the methods of synthesis of these hybrids, the antimicrobial activities of the compounds, their correlation with various groups present on the molecule, as well as their pharmaceutical properties.
Oriental Journal Of Chemistry
The emergence of multidrug-resistant pathogens have posed a major challenge to the treatment strategies for infectious diseases. In this study, a panel of eight novel pyrano-pyrazole heterocyclic moiety were prepared by multi-component one-pot reactions. In the first step Pyrano-pyrazole moiety prepared by single pot multicomponent condensation of Ethyl 3-oxobutanoate, pyridine-4-carbohydrazide, Propanedinitrile, and substituted benzaldehydes. In the second step above synthesized pyrano- pyrazole derivative react with different substituted phenyl amino-acetyl chloride derivative to give final compound. All the compounds were obtained in reasonable yields bearing their characteristic structure as inferred from the spectral analysis. All the synthesized compounds were screened for antimicrobial activity. Product B-1, B-5 and B-8 is found to have remarkable antibacterial activity. Products B-4 and B-7 are moderately active and compound B-5 and B-6 are found to have remarkable Antifunga...
Chemistry Journal of Moldova, 2019
In this study, new pyrazole, imidazole, pyrimidine derivatives having imidazo[4,5-b]indol moiety were successfully synthesized, elucidated by spectroscopic techniques, and evaluated as potential antimicrobial agents. The structure-activity relationship was investigated to obtain a better understanding of the relationship between the chemical structure of the synthesized compounds and their corresponding biological activity. Compounds 2b and 3b exhibited potent antibacterial activities against Bacillus subtilis bacteria comparable to that of Ampicillin standard. Structure-activity relationship studies revealed that the presence of withdrawing carbonyl group on 5-position of pyrazole moiety 2b, phenylpyrazole moiety 3b led to an enhancement in the antibacterial activity of pyrazole derivatives. Furthermore, the presence of carbonyl group on 2-position of the pyrimidine ring of compounds 4a, 5a and 6a has a significant effect on their antibacterial activity against Bacillus subtilis. The antifungal studies indicated that compounds 3b, 4b, 7 and 9 have comparable antifungal activity to that of standard Amphotericin B against Candida albicans and Aspergillus flavus fungi.
Journal of Pharmaceutical Research International, 2021
The aim of the study was to develop, synthesis, and characterise a novel 1,3,5-trisubstituted-2-pyrazolines derivative, as well as to evaluate its antifungal activity. The reaction of chalcone derivatives with succinic hydrazide in the presence of pyridine yielded the 1,3,5-tri-substituted-2-pyrazolines derivatives. Total 20 compounds has been synthesized and characterized by the IR, 1HNMR and mass spectral analysis. Antifungal activity of the compounds carried out onfour fungal strains i.e. Saccharomyces cerevisiae, A. Niger, C. Albicans and R. Oryzae in two different concentration i.e. 50 and 100 µg/ml by Agar-diffusion method using Cup-plate method. The usual antifungal medicine was ketoconazole. All of the synthesized 1,3,5-trisubstituted pyrazole compounds (ME1-ME8, CL1-CL8, BR1-BR4) showed medium to best action against examined organisms, according to antifungal activity data. The antifungal activity of compounds against fungal strains (Saccharomyces cerevisiae, A. Niger, Cand...