scholarly journals Synthesis and Antimicrobial Activity of 4-Arylthio- and 4 Alkylthiofunctionalized Pyrazolo[1,5-a]pyrazines

2019 ◽  
Vol 85 (1) ◽  
pp. 58-66
Author(s):  
Yevhenii Hrynyshyn ◽  
Hanna Musiichuk ◽  
Olena Komarovska-Porokhnyavets ◽  
Oksana Is’kiv ◽  
Nataliia Moskalenko ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Mass Spectra ◽  
Structural Modification ◽  
Bromoacetic Acid ◽  
Phosphorus Pentasulfide ◽  
First Case ◽  
Test Culture ◽  
Exocyclic Methylene ◽  
Derivatives Of ◽  
Test Cultures

The reaction of pyrazolo[1,5-a]pyrazine-4(5H)ones with phosphorus tribromoxide in boiling benzene yielded 4-bromopyrazolo[1,5-a]pyrazines, and the thionation with phosphorus pentasulfide in pyridine at 90 °C led to pyrazolo[1,5-a]pyrazine-4(5H)thiones. The synthesized bromine derivatives are electrophilic, and thiones are nucleophilic substrates. Their subsequent structural modification in the first case was carried out by interaction with thiophenols, and in the second case was conducted with functional halogenoalkanes. It was shown that bromides react with substituted thiophenols in dimethylformamide in the presence of potassium carbonate at 90 °C to form 4-arylthiopyrazolo[1,5-a]pyrazines with yields of 65–83 %. 4-S-methyl-functionalized derivatives of pyrazole[1,5-a]pyrazines with yields of 60–78 % were easily obtained by the alkylation of pyrazole[1,5-a]pyrazin-4(5H)thiones with a-bromoketones, bromoacetic acid, ethyl bromoacetate and bromoacetonitrile in the K2CO3—DMF system at room temperature. The composition of all synthesized compounds is in agreement with the results of elemental analysis and mass spectra. Their structure is confirmed by NMR 1H and 13C spectra. In particular, in the NMR 1H spectra of 4-arylthiopyrazolo[1,5-a]pyrazines, in addition to the characteristic signals of the pyrazole and pyrazine nuclei, signals of protons of thioaryl substituents are present in the range of 7.04 –8.05 ppm, and in NMR spectra of the 1H 4-S-methylfunctionalized derivatives of pyrazole[1,5-a]pyrazines signals of exocyclic methylene protons are present at 4.11– 5.02 ppm. Promising derivatives with antibacterial activity against the test cultures S. aureus (MIC = 7.8 g/mL), M. luteum (MIC = 3.9 g/mL), and antifungal activity against the test culture of fungus A. niger (MIC = 7.8 g/mL) were determined among 4-S-substituted pyrazole[1,5-a]pyrazines as a result of studies of the antimicrobial activity.

scholarly journals Synthesis and Antimicrobial Activity of Calycanthaceous Alkaloid Analogues

2016 ◽  
Vol 11 (10) ◽  
pp. 1934578X1601101
Author(s):  
Shaojun Zheng ◽  
Longbo Li ◽  
Yu Wang ◽  
Rui Zhu ◽  
Hogjin Bai ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Structural Modification ◽  
Antimicrobial Agents ◽  
Pathogenic Fungi ◽  
Curvularia Lunata ◽  
Plant Pathogenic Fungi ◽  
H Nmr ◽  
High Degree ◽  
Derivatives Of ◽  
C Nmr

A series of 24 novel derivatives of the calycanthaceous alkaloids with a tetrahydropyrroloindol-based core structure was synthesized from tryptophan in good yields. Their structures were characterized by IR, 1H NMR, and 13C NMR spectroscopy and ESI-MS. The synthesized compounds were evaluated against a wide variety of plant pathogenic fungi. Compound a9 exhibited a high degree of activity against Curvularia lunata, with 91.0% activity at a concentration of 100 μg mL−1 and with an EC50 of 44.6 μg mL−1. a7, a8, a13, and a17 exhibited high degrees of activity against Sclerotinia sclerotiorum, with a8 being the most effective with an EC50 of 38.4 μg mL−1. Compound a9 illustrated activity against Botrytis cinerea, with an EC50 of 79.5 μg mL−1. Considering the compounds evaluated, the alkyl substituents of the chain may contribute to the significant variations in fungicidal potency. The structure antifungal activity relationships are also discussed. These results will pave the way for further design, structural modification, and development of calycanthaceous alkaloids as antimicrobial agents.

scholarly journals THE STUDY OF THE ANTIMICROBIAL ACTIVITY OF SOME NEW AZO DERIVATIVES OF PYRIDOXINE AND THEIR ZINC COMPLEXES

2012 ◽  
Vol 17 (2) ◽  
pp. 60-62
Author(s):  
N. N. Aliyev ◽  
F. A. Heydarova
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Activity ◽  
Maximum Dose ◽  
Zinc Complexes ◽  
Low Toxicity ◽  
Azo Derivatives ◽  
First Time ◽  
Derivatives Of ◽  
Candia Albicans ◽  
Test Cultures

For the first time with the use of conventional techniques the overall toxicity and the antimicrobial activity of some new substances - pyridoxine azo derivatives (mercurions), obtained an international registration (CAS, USA) and their zinc-complexes have been studied. St. aureus, E.coli, Pseudomonas aeruginosa, and Candia albicans were used as a test cultures. The investigated compounds were established to have low toxicity (LD 50 failed to detect, with a maximum dose of introduced animals as 0.01 g ≈ 20 g), and some of them were shown to have pronounced antimicrobial activity. In contrast to free mercurions their zinc complexes show activity against strains of some microorganisms (St. aureus, Candida albicans), as well as similar antimicrobial activity in the lower (2-4 fold) concentrations.

scholarly journals Determination of the antibacterial activity of flavonoids from callus Scutellaria galericulata L. for the development of a functional curd product

2020 ◽  
Vol 82 (1) ◽  
pp. 178-182
Author(s):  
O. V. Belashova ◽  
A. V. Zaushintsena ◽  
L. A. Levanova ◽  
Y. V. Zakharova ◽  
A. A. Mar ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Effect ◽  
Antimicrobial Effect ◽  
Preventive Action ◽  
Inhibition Of Growth ◽  
Test Culture ◽  
The Common ◽  
Different Strains ◽  
Test Cultures

The antimicrobial effect of extracts from callus of the common skullcap with the prospect of using in the recipe of a functional curd product for therapeutic and preventive action is studied. It is known that plants of the genus skullcap contain phenolic compounds that cause antimicrobial action, the most common among them are flavonoids-baykalin, scutellarein, hydrolyzed to glucuronic acid and aglycones-baykalein and scutellarein, vogonin, etc. the Study of antimicrobial activity was carried out in accordance with the requirements of The state Pharmacopoeia XI edition. Antimicrobial activity was determined in relation to 15 test cultures by diffusion in agar. The method is based on the assessment of inhibition of growth of test cultures of microorganisms by certain concentrations of the test object. Rod-shaped bacteria (Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, Serracia marcescens, Escherichia coli, Morganella morganii, Hafnia alvei, Bacillus cereus), coccus microflora (Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecium), different strains of fungi of the genus Candida (Candida non-albicans № 136, 138, 142, 144). The result was evaluated according to the following criteria: “-“ – growth of the test culture (there is no antibacterial effect); “+” – no growth (the antibacterial effect is pronounced); “±” – inhibition of growth (bacteriostatic action).

scholarly journals Determination of antimicrobial activity of some 1,2,4-triazole derivatives

2018 ◽  
Vol 9 (2) ◽  
pp. 203-208 ◽  
Author(s):  
M. S. M. Alrawashdeh
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Klebsiella Pneumonia ◽  
Pathological Changes ◽  
Infectious Bronchitis ◽  
E Coli ◽  
Compound Ii ◽  
Derivatives Of ◽  
Test Cultures

We carried out MIC of the derivatives of 1,2,4-triazole II (4-((5-nitrofuran-2-yl)methyleneamino)-1-propyl-4H-1,2,4-triazolium bromide) and I (N-((5-nitrofuran-2-yl)methylene)-4H-4-amino-1,2,4-triazolidium chloride) against Escherichia coli ATCC 3912/4 and E. coli k88ad, Staphylococcus aureus ATCC 25923 and S. aureus k99, Klebsiella pneumonia k56 and Salmonella typhimurium 144, S. enteritidis. All test cultures were sensitive to compound II at concentrations of 1,25–0,039 μg/ml. Similar MIC (0,039 μg/ml) of compounds II and I were set for E. coli k88a and S. aureus k99 test cultures – 0,156 μg/ml. Only S. aureus ATCC 25923 and K. pneumonia k56 had sensitivity to ceftriaxone (MIC = 0,097 μg/ml). Antiviral activity of Trifuzol (piperidine 2-[5-(furan-2-il)-4-phenil-1,2,4-triazol-3-ilthio]acetate) and avistim (morpholines 3-(4-pyridyl)-1,2,4-triazolil-5-thioacetate) against the chicken infectious bronchitis virus (VIB) strain 4/91 was characterized by a decrease in mortality and pathological changes of chicken embryos (CE) which were induced by the virus. Death of infected CE provoked by the strain 4/91 of VIB in dilution 10–3 occurred at 57.1%. The reduction in the percentage of deaths of CE infected by the virus in dilution 10–3 in the presence of Avistim was 28.6%, and with Trifuzol 14.3%. The use of avistim and Trifuzol compounds reduced VIB infectious activity when it was cultivated in CE, reducing the titre of the virus (strain 4/91) by 3 lg EID 50 cm–3.

QSAR Analysis of Selected Antimicrobial Structures Belonging to Nitro-derivatives of Heterocyclic Compounds

2020 ◽  
Vol 17 (2) ◽  
pp. 214-225 ◽  
Author(s):  
Piotr Kawczak ◽  
Leszek Bober ◽  
Tomasz Bączek
Keyword(s):  
Antimicrobial Activity ◽  
Heterocyclic Compounds ◽  
Molecular Descriptors ◽  
Microbiological Activity ◽  
Activity Data ◽  
Qsar Analysis ◽  
Qsar Models ◽  
Nitro Derivatives ◽  
Semi Empirical ◽  
Derivatives Of

Background: Nitro-derivatives of heterocyclic compounds were used as active agents against pathogenic microorganisms. A set of 4- and 5-nitroimidazole derivatives exhibiting antimicrobial activity was analyzed with the use of Quantitative Structure-Activity Relationships (QSAR) method. The study included compounds used both in documented treatment and those described as experimental. Objective: The purpose of this study was to demonstrate the common and differentiating characteristics of the above-mentioned chemical compounds alike physicochemically as well as pharmacologically based on the quantum chemical calculations and microbiological activity data. Methods: During the study PCA and MLR analysis were performed, as the types of proposed chemometric approach. The semi-empirical and ab initio level of in silico molecular modeling was performed for calculations of molecular descriptors. Results: QSAR models were proposed based on chosen descriptors. The relationship between the nitro-derivatives structure and microbiological activity data was able to class and describe the antimicrobial activity with the use of statistically significant molecular descriptors. Conclusion: The applied chemometric approaches revealed the influential features of the tested structures responsible for the antimicrobial activity of studied nitro-derivatives.

Inductive effect in EI-mass spectra of some 5,6-dihalogenides and 5,6-halohydrins of 5α-cholestan-3β-ol and 3β-acetoxy-5α-cholestane

1982 ◽  
Vol 47 (11) ◽  
pp. 2946-2960 ◽  
Author(s):  
Antonín Trka ◽  
Alexander Kasal
Keyword(s):  
Mass Spectra ◽  
Inductive Effect ◽  
Molecular Ions ◽  
Hydroxyl Group ◽  
Halogen Atoms ◽  
Derivatives Of

Partial EI-mass spectra of 3β-hydroxy- and 3β-acetoxy-5α-cholestanes substituted in positions 5α-, 6β- or 5α,6β- with a hydroxyl group or halogen atoms (fluorine, chlorine, bromine) are presented. The molecular ions of 5α,6β-disubstituted derivatives of 3β-hydroxy-5α-cholestane (or of its 3-acetate) are considerably more stable than the corresponding monosubstituted derivatives if at least one of the pair of the vicinal substituents is chlorine or fluorine. This increase in stability, most striking in 5α- and 6β-fluoro compounds, is explained by the inductive effect.

scholarly journals Novel Derivatives of 4-Methyl-1,2,3-Thiadiazole-5-Carboxylic Acid Hydrazide: Synthesis, Lipophilicity, and In Vitro Antimicrobial Activity Screening

2021 ◽  
Vol 11 (3) ◽  
pp. 1180
Author(s):  
Kinga Paruch ◽  
Łukasz Popiołek ◽  
Anna Biernasiuk ◽  
Anna Berecka-Rycerz ◽  
Anna Malm ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Carboxylic Acid ◽  
Bacterial Infections ◽  
Acid Hydrazide ◽  
Antimicrobial Effect ◽  
In Vitro Antimicrobial Activity ◽  
Research Goal ◽  
New Compounds ◽  
Derivatives Of

Bacterial infections, especially those caused by strains resistant to commonly used antibiotics and chemotherapeutics, are still a current threat to public health. Therefore, the search for new molecules with potential antimicrobial activity is an important research goal. In this article, we present the synthesis and evaluation of the in vitro antimicrobial activity of a series of 15 new derivatives of 4-methyl-1,2,3-thiadiazole-5-carboxylic acid. The potential antimicrobial effect of the new compounds was observed mainly against Gram-positive bacteria. Compound 15, with the 5-nitro-2-furoyl moiety, showed the highest bioactivity: minimum inhibitory concentration (MIC) = 1.95–15.62 µg/mL and minimum bactericidal concentration (MBC)/MIC = 1–4 µg/mL.

Ester-Functionalized, Wide-Bandgap Derivatives of PM7 for Simultaneous Enhancement of Photovoltaic Performance and Mechanical Robustness of All-Polymer Solar Cells

2021 ◽  
Author(s):  
Hoseon You ◽  
Austin Jones ◽  
Boo Soo Ma ◽  
Geon-U Kim ◽  
Seungjin Lee ◽  
...  
Keyword(s):  
Solar Cells ◽  
Structural Modification ◽  
Polymer Solar Cells ◽  
Photovoltaic Performance ◽  
Wide Bandgap ◽  
Derivatives Of

In this study, two wide-bandgap PM7 polymer derivatives are developed via simple structural modification of the fused-accepting unit by incorporating ester groups on terthiophene at different positions (i.e., two ester...

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