scholarly journals Syntheses, Evaluation and Characterization of Some 1, 3, 4-Oxadiazoles as Antimicrobial Agents

2009 ◽  
Vol 6 (4) ◽  
pp. 1133-1138 ◽  
Author(s):  
Niti Bhardwaj ◽  
S. K. Saraf ◽  
Pankaj Sharma ◽  
Pradeep Kumar

1,3,4-Oxadiazoles show various biological activities and have been synthesized from different compounds. 1,3,4-oxadiazole is popularly known for its antimicrobial, anti-inflammatory, pesticidal and antihypertensive activitiesetc. It is well known that the synthesis of heterocyclic compounds tend to contain multi-structure in a molecule. The ring formation involves the condensation reaction. The challenge is to develop the ring system by incorporating the indole nucleus into it through the proposed reaction scheme. There are two free positions for the substitution in the oxadiazole ring system. In this study, it was planned to incorporate the oxadiazole ring system into indole ring. Synthesis of derivatives of 1,3,4-oxadiazoles from different benzaldehydes Characterization of the synthesized compounds along with their antimicrobial activity on different strains.

2020 ◽  
Vol 26 (8) ◽  
pp. 867-904 ◽  
Author(s):  
Maria Fesatidou ◽  
Anthi Petrou ◽  
Geronikaki Athina

Background: Bacterial infections are a growing problem worldwide causing morbidity and mortality mainly in developing countries. Moreover, the increased number of microorganisms, developing multiple resistances to known drugs, due to abuse of antibiotics, is another serious problem. This problem becomes more serious for immunocompromised patients and those who are often disposed to opportunistic fungal infections. Objective: The objective of this manuscript is to give an overview of new findings in the field of antimicrobial agents among five-membered heterocyclic compounds. These heterocyclic compounds especially five-membered attracted the interest of the scientific community not only for their occurrence in nature but also due to their wide range of biological activities. Method: To reach our goal, a literature survey that covers the last decade was performed. Results: As a result, recent data on the biological activity of thiazole, thiazolidinone, benzothiazole and thiadiazole derivatives are mentioned. Conclusion: It should be mentioned that despite the progress in the development of new antimicrobial agents, there is still room for new findings. Thus, research still continues.


Marine Drugs ◽  
2020 ◽  
Vol 18 (10) ◽  
pp. 505
Author(s):  
Joyce A. Nieva ◽  
Jan Tebben ◽  
Urban Tillmann ◽  
Sylke Wohlrab ◽  
Bernd Krock

Spirolides belong to a group of marine phycotoxins produced by the marine planktonic dinophyte Alexandrium ostenfeldii. Composed of an imine moiety and a spiroketal ring system within a macrocylcle, spirolides are highly diverse with toxin types that vary among different strains. This study aims to characterize the spirolides from clonal A. ostenfeldii strains collected from The Netherlands, Greenland and Norway by mass spectral techniques. The structural characterization of unknown spirolides as inferred from high-resolution mass spectrometry (HR-MS) and collision induced dissociation (CID) spectra revealed the presence of nine novel spirolides that have the pseudo-molecular ions m/z 670 (1), m/z 666 (2), m/z 696 (3), m/z 678 (4), m/z 694 (5), m/z 708 (6), m/z 720 (7), m/z 722 (8) and m/z 738 (9). Of the nine new spirolides proposed in this study, compound 1 was suggested to have a truncated side chain in lieu of the commonly observed butenolide ring in spirolides. Moreover, there is indication that compound 5 might belong to new spirolide subclasses with a trispiroketal ring configuration having a 6:5:6 trispiroketal ring system. On the other hand, the other compounds were proposed as C- and G-type SPX, respectively. Compound 7 is proposed as the first G-type SPX with a 10-hydroxylation as usually observed in C-type SPX. This mass spectrometry-based study thus demonstrates that structural variability of spirolides is larger than previously known and does not only include the presence or absence of certain functional groups but also involves the triketal ring system.


2017 ◽  
Vol 73 (9) ◽  
pp. 1329-1332
Author(s):  
Md. Serajul Haque Faizi ◽  
Necmi Dege ◽  
Sergey Malinkin ◽  
Tetyana Yu. Sliva

The title compound, C25H20N2, (I), was synthesized from the condensation reaction of anthracene-9-carbaldehyde and tryptamine in dry ethanol. The indole ring system (r.m.s. deviation = 0.016 Å) makes a dihedral angle of 63.56 (8)° with the anthracene ring (r.m.s. deviation = 0.023 Å). There is a short intramolecular C—H...N interaction present, and a C—H...π interaction involving the two ring systems. In the crystal, the indole H atom forms an intermolecular N—H...π interaction, linking molecules to form chains along theb-axis direction. There are also C—H...π interactions present, involving the central and terminal rings of the anthracene unit, linking the chains to form an overall two-dimensional layered structure, with the layers parallel to thebcplane. The density functional theory (DFT) optimized structure, at the B3LYP/6-311 G(d,p) level, is compared with the experimentally determined molecular structure in the solid state.


2020 ◽  
Vol 24 (15) ◽  
pp. 1669-1716 ◽  
Author(s):  
Thoraya A. Farghaly ◽  
Sami A. Al-Hussain ◽  
Zeinab A. Muhammad ◽  
Magda A. Abdallah ◽  
Magdi E. A. Zaki

Perimidines are peri-naphtho-fused derivatives of pyrimidine. They are of particular interest as they are a rare example of an azine in which the lone pair of electrons of pyrrole-like nitrogen participates in the π-system of the molecule. Perimidine is an interesting class of heterocyclic compounds. Various synthetic analogs of perimidines have been prepared and evaluated for many pharmacological activities in different models with desired findings. They exhibit biological activities as antitumor, antiulcer, antimicrobial, and antifungal agents. This review is an attempt to organize the synthesis and chemical reactions of perimidine analogs reported to date systematically since 1955. It should be noted that this review is the first one that includes the preparation and reactions of the perimidine ring.


2020 ◽  
Vol 20 (1) ◽  
pp. 4-28
Author(s):  
Tarawanti Verma ◽  
Manish Sinha ◽  
Nitin Bansal

Benzene is a six-membered hydrocarbon ring system and if three carbon-hydrogen units of benzene ring are replaced by nitrogen atoms then triazine is formed. Triazines are present in three isomeric forms 1,2,3- triazine, 1,2,4-triazine, and 1,3,5-triazine according to the position of the nitrogen atom. These are weak bases having weaker resonance energy than benzene, so nucleophilic substitution is preferred than electrophilic substitution. Triazine is an interesting class of heterocyclic compounds in medicinal chemistry. Numerous synthetic derivatives of triazine have been prepared and evaluated for a wide spectrum of biological activities in different models with desired findings such as antibacterial, antifungal, anti-cancer, antiviral, antimalarial, antiinflammatory, antiulcer, anticonvulsant, antimicrobial, insecticidal and herbicidal agents. Triazine analogs have exposed potent pharmacological activity. So, triazine nucleus may be considered as an interesting core moiety for researchers for the development of future drugs.


2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Omoruyi G. Idemudia ◽  
Alexander P. Sadimenko ◽  
Anthony J. Afolayan ◽  
Eric C. Hosten

Two Schiff base ligands Ampp-Sn1and Bmpp-Sn2, afforded by a condensation reaction between sulfanilamide and the respective acylpyrazolone carbonyl precursors, their Mn(II), Co(II), Ni(II), and Cu(II) complexes prepared by the reaction of ligands and corresponding metal salts in aqueous solutions, were synthesized and then characterized by both analytical and spectroscopic methods, in a view to developing new improved bioactive materials with novel properties. On the basis of elemental analysis, spectroscopic and TGA results, transition metal complexes, with octahedral geometry having two molecules of the bidentate keto-imine ligand each, have been proposed. The single crystal structure of Bmpp-Sn according to X-ray crystallography showed a keto-imine tautomer type of Schiff base, having three intramolecular bonds, one short N2⋯H2⋯O3 hydrogen bond of 1.90 Å and two long C13⋯H13⋯O2 and C32⋯H32⋯O3 hydrogen bonds of 2.48 Å. A moderate to low biological activities have been exhibited by synthesized compounds when compared with standard antimicrobial agents on screening the synthesized compounds againstStaphylococcus aureus,Bacillus pumilus,Proteus vulgaris, andAeromonas hydrophilafor antibacterial activity and against free radical 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) for antioxidant activity.


Author(s):  
Praveen Kumar Sharma ◽  
Reena Makkar

ABSTRACTIn recent days, heterocycles and their derivatives have become strong reflection in medicinal research and pharmaceutical fields because of theirpractical pharmacological and biological activities. Organic compounds; mainly heterocyclic compounds are wealthy in natural world and containextra value because their structural subunits are established in many natural products such as enzymes, vitamins, antibiotics, acids, and hormones.Thiazine nucleuses found in compounds have variety of pharmacological activities such as antitumor, antimicrobial, antibacterial, antifungal, antiviral,and anti-inflammatory. This review spotlight on the substituted thiazines with possible antimicrobial activities that are at the present in development.Keywords: Antibacterial, Substituted thiazines, Antimicrobial agents.


2020 ◽  
Vol 8 (1) ◽  
pp. 12-18
Author(s):  
Alya A. Dawood ◽  
Shireen R. Mmohammed ◽  
Mohammed Mahmoud

Series of new Schiff bases and their derivatives (Oxazepine) have been synthesized during two steps. The first step synthesis of imines derivatives (1-10) by the condensation reaction of 1, 7-diaminohepatane and 1,8-diaminooctane with different substituted aromatic aldehydes by using glacial acetic acid as catalyst. The second step includes reaction of the prepared Schiff bases derivatives with phathalic anhydride in dry benzene to obtain   seven-membered heterocyclic ring derivatives (11-15).  The biological activities of some prepared compounds were also studied against different kinds of bacteria. The new derivatives were confirmed by suing a range of experimental techniques including 1HNMR, 13C NMR, IR and Mass spectra.


2016 ◽  
Vol 10 (3) ◽  
pp. 271-278
Author(s):  
Thanaa Al-muamin ◽  
◽  
Naeemah Al-lami ◽  
Suroor Rahman ◽  
Rana Ali ◽  
...  

Novel derivatives of 1-(´1, ´3, ´4, ´6-tetra benzoyl-β-D-fructofuranosyl)-1H- benzotriazole and 1-(´1, ´3, ´4, ´6-tetra benzoyl-β-D-fructofuranosyl)-1H-benzotriazole carrying Schiff bases moiety were synthesised and fully characterised. The protection of D-fructose using benzoyl chloride was synthesized, followed by nucleophilic addition/elimination between benzotriazole and chloroacetyl chloride to give 1-(1- chloroacetyl)-1H-benzotriazole. The next step was condensation reaction of protected fructose and 1-(1-chloroacetyl)-1H-benzotriazole producing a new nucleoside analogue. The novel nucleoside analogues underwent a second condensation reaction with different aromatic and aliphatic amines to provide new Schiff bases. The prepared analogues were characterised by FT-IR, 1H NMR, 13C NMR, HRMS(EI+) spectra. These analogues were tested against different bacteria to evaluate them as antimicrobial agents.


2020 ◽  
Vol 20 (5) ◽  
pp. 418-429 ◽  
Author(s):  
Asmaa F. Kassem ◽  
Fatimah Alshehrei ◽  
Eman M.H. Abbas ◽  
Thoraya A. Farghaly

Background & Objective:Quinazolines and their fused systems are noteworthy in pharmaceutical chemistry due to their wide range of biological activities.Methods:A direct and efficient approach for the synthesis of new series of fused quinazolines with triazole, thiazole, benzimidazole and tetrazole has been preceded via the reaction of quinazoline thione derivative with halogenated compounds or cyclocondensation of arylidene of quinazoline derivative with heterocyclic amines. Also, dibenzo[b,e][1,4]thiazepine derivatives was synthesized through the reaction of 2,6-bis-(2-chloro-benzylidene)-cyclohexanone with o-aminothiophenol.Results:The structures of all new synthesized heterocyclic compounds were confirmed and discussed on the bases of spectral data. The utility of the preparation and design of the above mentioned compounds has been shown to be clear in the results of their antimicrobial activity which revealed that some derivatives have potent activity exceeding or similar to the activity of the reference drugs.Conclusion:The insertion of triazole or thiazole moieties to be fused with quinazoline ring helps to enhance its antimicrobial activity.


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