scholarly journals EVALUATION OF ANTIMICROBIAL ACTIVITIES OF MICROWAVE-IRRADIATION SYNTHESIZED TETRADENTATE (N2O2 DONOR) SCHIFF BASE AND ITS Cu(II) COMPLEXES

2022 ◽  
Vol 14 (04) ◽  
pp. 2604-2612
Author(s):  
K. P. Srivastava ◽  
U. S. Yadav ◽  
Pragya Singh
Keyword(s):  
Schiff Base ◽  
Microwave Irradiation ◽  
Antimicrobial Activities

Study of Physico-chemical Characteristics and Pharmacological Effects of 1-Ethyl-Salicyldene-bis-Ethylene-Diamine and Its Complex with Mn(II)

2019 ◽  
Vol 70 (7) ◽  
pp. 2534-2537
Author(s):  
Gladiola Tantaru ◽  
Mihai Apostu ◽  
Antonia Poiata ◽  
Mihai Nichifor ◽  
Nela Bibire ◽  
...  
Keyword(s):  
Schiff Base ◽  
Chemical Structure ◽  
Antimicrobial Activities ◽  
Ethylene Diamine ◽  
Chemical Characteristics ◽  
Gram Negative Bacteria ◽  
Pharmacological Effects ◽  
Physico Chemical ◽  
Anti Inflammatory ◽  
Inflammatory Effect

The paper presents the synthesis of a new complex combination of a Bis-Schiff base with Mn(II) ions with great potential for antimicrobial and anti-inflammatory activity. A new complex of the Salen-type ligand, 1-ethyl-salicylidene-bis-ethylene diamine was synthetized using Mn(II) ions. The chemical structure was confirmed through 1H-NMR and IR spectroscopy. The antimicrobial activities of the Bis-Schiff base and its complex were tested in comparison with Ampicillin, Chloramphenicol, Tetracycline, Ofloxacin and Nystatin. Those compounds were found to be active against Gram-positive or Gram-negative bacteria, and had an anti-inflammatory effect comparable to that of Indomethacin.

New Potential Biologically Active Compounds: Synthesis and Characterization of Urea and Thiourea Derivativpes Bearing 1,2,4-oxadiazole Ring

2020 ◽  
Vol 17 (7) ◽  
pp. 525-534 ◽  
Author(s):  
Nevin Arıkan Ölmez ◽  
Faryal Waseer
Keyword(s):  
Microwave Irradiation ◽  
Room Temperature ◽  
Antimicrobial Activities ◽  
Phenyl Isocyanate ◽  
Single Step ◽  
Biologically Active Compounds ◽  
Biologically Active ◽  
Active Compounds ◽  
Thiourea Derivatives ◽  
Acyl Chlorides

Background: Urea, thiourea, and 1,2,4-oxadiazole compounds are of great interest due to their different activities such as anti-inflammatory, antiviral, analgesic, fungicidal, herbicidal, diuretic, antihelminthic and antitumor along with antimicrobial activities. Objective: In this work, we provide a new series of potential biologically active compounds containing both 1,2,4-oxadiazole and urea/thiouprea moiety. Materials and Methods: Firstly, 5-chloromethyl-3-aryl-1,2,4-oxadiazoles (3a-j) were synthesized from the reaction of different substituted amidoximes (2a-j) and chloroacetyl chloride in the presence of pyridine by conventional and microwave-assisted methods. In the conventional method, 1,2,4-oxadiazoles were obtained in two steps. O-acylamidoximes obtained in the first step at room temperature were heated in toluene for an average of one hour to obtain 1,2,4-oxadiazoles. The yields varied from 70 to 96 %. 1,2,4-oxadiazoles were obtained under microwave irradiation in a single step in a 90-98 % yield at 160 °C in five minutes. 5-aminomethyl-3-aryl-1,2,4- oxadiazoles (5a-j) were obtained by Gabriel amine synthesis in two steps from corresponding 5-chloromethyl-3- aryl-1,2,4-oxadiazoles. Finally, twenty new urea (6a-j) and thiourea (7a-j) compounds bearing oxadiazole ring were synthesized by reacting 5-aminomethyl-3-aryl-1,2,4-oxadiazoles with phenyl isocyanate and isothiocyanate in tetrahydrofuran (THF) at room temperature with average yields (40-70%). Results and Discussions: An efficient and rapid method for the synthesis of 1,2,4-oxadiazoles from the reaction of amidoximes and acyl halides without using any coupling reagent under microwave irradiation has been developed, and twenty new urea/thiourea compounds bearing 1,2,4-oxadiazole ring have been synthesized and characterized. Conclusion: We have synthesized a new series of urea/thiourea derivatives bearing 1,2,4-oxadiazole ring. Also facile synthesis of 3,5-disubstituted 1,2,4-oxadiazoles from amidoximes and acyl chlorides under microwave irradiation was reported. The compounds were characterized using FTIR, 1H NMR, 13C NMR, and elemental analysis techniques.

scholarly journals Synthesis and Evaluation of Schiff Bases of 4-Amino-5-(chlorine substituted phenyl)-4H-1,2,4-triazole-3-thione as Antimicrobial Agents

2020 ◽  
Vol 41 (1) ◽  
pp. 26-35
Author(s):  
Kishor Devkota ◽  
Govinda Pathak ◽  
Bhushan Shakya
Keyword(s):  
Schiff Base ◽  
Schiff Bases ◽  
Antimicrobial Agents ◽  
Triazole Ring ◽  
Antimicrobial Activities ◽  
Biologically Active ◽  
Spectral Techniques ◽  
Schiff Base Derivatives ◽  
Bacteria And Fungi ◽  
Different Strains

Triazole ring system has attracted a continuously growing interest of synthetic organic chemists and those dealing with the medicinal compounds due to its versatile potential to interact with biological systems. Schiff bases are also considered as one of the most biologically active compounds.  The aim of the present study was to synthesize new Schiff bases bearing triazole nucleus and to assess their antimicrobial activities. Four new Schiff base derivatives of 1,2,4-triazole-3-thione were synthesized by combining two different pharmacophores viz. triazole nucleus and Schiff base moiety and were characterized by spectral techniques (UV, FT-IR, and NMR). The Schiff bases were evaluated for antibacterial (Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae) and antifungal (Candida albicans) activities. The synthesized compounds exhibited good to moderate activities against different strains of bacteria and fungi tested.

New di- and triorganotin(IV) carboxylates derived from a Schiff base: synthesis, characterization and in vitro antimicrobial activities

2015 ◽  
Vol 29 (5) ◽  
pp. 305-313 ◽  
Author(s):  
Letícia C. Dias ◽  
Geraldo M. de Lima ◽  
Jacqueline A. Takahashi ◽  
José D. Ardisson
Keyword(s):  
Schiff Base ◽  
Antimicrobial Activities

scholarly journals Syntheses, Characterization, Crystal Structures and Antimicrobial Activity of Schiff Base Copper(II) Complexes Derived from 2-Bromo-6-((2-(isopropylamino) ethylimino)methyl)phenol

2021 ◽  
Vol 68 (4) ◽  
pp. 1008-1015
Author(s):  
Yong Yuan ◽  
Xi-Kun Lu ◽  
Gao-Qi Zhou ◽  
Xiao-Yang Qiu
Keyword(s):  
Antimicrobial Activity ◽  
Schiff Base ◽  
Single Crystal ◽  
Elemental Analysis ◽  
Structure Determination ◽  
Antimicrobial Activities ◽  
X Ray ◽  
Zwitterionic Form ◽  
Square Planar ◽  
Vis Spectroscopy

Three new copper(II) complexes, [Cu(LH)2]Br2 (1), [Cu(LH)2]NCS2 (2), and [Cu(LH)2](NO3)2 (3), where LH is the zwitterionic form of 2-bromo-6-((2-(isopropylamino)ethylimino)methyl)phenol (HL), were synthesized and characterized by elemental analysis, IR and UV-vis spectroscopy. The structures of the complexes were further confirmed by single crystal X-ray structure determination. All compounds are mononuclear copper(II) complexes. The Cu atoms in the complexes are coordinated by two imino N and two phenolate O atoms from two LH ligands, forming square planar coordination. The compounds were assayed for their antimicrobial activities.

scholarly journals Synthesis of bisquinolines through conventional and unconventional energy sources

2011 ◽  
Author(s):  
◽  
Talent Raymond Makhanya
Keyword(s):  
Schiff Base ◽  
Microwave Irradiation ◽  
Critical Factor ◽  
Cost Effective ◽  
Synthetic Methods ◽  
Parasite Life Cycle ◽  
Immunodeficiency Virus ◽  
Alkaline Conditions ◽  
Tropical Areas ◽  
Resistant Strains

Malaria, the most prevalent parasitic disease, is considered a neglected disease owing to insufficient research and development in synthesis and therapy worldwide. Therapy failures are frequent and are due to a variety of factors such as the intrinsic characteristics of the disease, conditions of transmission, and the difficult control of spreading through tropical areas. Primary factors are the complexity of the parasite life cycle and the development of drug resistance. Another critical factor is the increasing number of immune-compromised patients that suffer from malaria and human immunodeficiency virus (HIV) co-infections. Most of the drugs currently available to treat malaria are quinoline derivatives modelled on the quinine molecule, found in the bark of Cinchona trees. Over the last 50 years the use of quinine has declined owing to the development of synthetic 4-aminoquinolines such as chloroquine. However, the malaria parasite is rapidly becoming resistant to the drugs currently available. Recently bisquinoline compounds were found more potent than chloroquine against both chloroquine-sensitive and resistant strains of malaria; this improved efficacy and prompted an increased interest in the design of these anti-malarial drugs. Although several synthetic methods are available to synthesise bisquinolines, we report the synthesis of bisquinolines from simple, readily available and cost- effective starting compounds. The synthesis was accomplished in four reaction steps using the Claisen condensation, Vilsmeir-Haack reaction, formation of a Schiff base and thermal cyclization, sequentially. We used a conventional energy source and microwave irradiation for the synthesis, wherever possible, of 2, 4-dichloro-3, 4'-biquinoline and 2, 4-dichloro-7'-methoxy-3, 4'-biquinoline. In the first step, 3-acyl-2, 4-dihydroxyquinoline is synthesised from an equimolar mixture of methyl-2-aminobenzoate and ethyl acetoacetate by microwave irradiation for 3 minutes; the yield is 90 % whereas by 6 hours refluxing the yield is 75 %. This is followed by the synthesis of 3-chloro-3-(2,4-dichloroquinolin-3yl) acrylaldehyde, by combining DMF and POCl3 at 00C to form the electrophile which reacts with 3-acyl-2,4-dihydroxyquinoline under microwave irradiation for 5 minutes; the yield is 65 % whereas by 6 hours refluxing the yield is 50 %. In the next step, several protocols to prepare a Schiff base 3-chloro-3-(2, 4-dichloroquinolin-3-yl) allylidene aniline are investigated with the best yield of 75% obtained by microwave irradiation for 5 minutes. Subsequently three aniline derivatives viz, 4-methoxyaniline, 4-chloroaniline and 4-methylaniline, are used as substrate to prepare 3-chloro-3-(2,4-dichloroquinolin-3-yl) allylidene-4-methoxyaniline, 3-chloro-3-(2 ,4-dichloroquinolin-3-yl) allylidene-4-methylaniline and 3-chloro-3-(2, 4-dichloroquinolin-3-yl) allylidene-4-chloro aniline at 68, 78 and 64 % yield, respectively. In the final step, 2, 4-dichloro-3, 4'-biquinoline is prepared; several methods were investigated, however, the best yield is 24 % which is obtained under alkaline conditions in the presence of K2CO3 and DMF by microwave irradiation for 10 minutes. The 2, 4-dichloro-7'-methoxy-3, 4'-biquinoline derivative is also prepared in 18 % yield under the same alkaline conditions. The outline of the total synthesis of bisquinoline is presented graphically below.

scholarly journals Synthesis, Characterization and Antimicrobial Activities of Sulfadiazine Schiff Base and Phenyl Dithiocarbamate Mixed Ligand Metal Complexes

2018 ◽  
Vol 08 (08) ◽  
pp. 346-354
Author(s):  
Benjamin Chibuzo Ejelonu ◽  
Sulaiman Adeoye Olagboye ◽  
Oluwatoba Emmanuel Oyeneyin ◽  
Oladipo Adebayo Ebiesuwa ◽  
Oluwatomisin Emmanuel Bada
Keyword(s):  
Schiff Base ◽  
Metal Complexes ◽  
Antimicrobial Activities ◽  
Mixed Ligand

scholarly journals Structural and Biological Studies on Transition Metal Complexes of 4-Aminoantipyrine Derivative

2020 ◽  
Vol 32 (11) ◽  
pp. 2846-2854
Author(s):  
V. Soundaranayaki ◽  
A. Kulandaisamy
Keyword(s):  
Magnetic Susceptibility ◽  
Schiff Base ◽  
Antimicrobial Activities ◽  
Esr Spectra ◽  
Molar Conductance ◽  
Schiff Base Complexes ◽  
Binding Potential ◽  
Planar Geometry ◽  
Pyramidal Geometry ◽  
Biological Studies

Novel tetra dentate Cu(II), Ni(II), Co(II), VO(II) and Zn(II) Schiff base complexes have been synthesized from salicylidene-4-iminoantipyrine and tyrosine. The synthesized Schiff base complexes was characterized by powder X-ray diffraction studies (XRD), scanning electron microscopy (SEM), FT-IR, ESR, 1H NMR, 13C NMR, UV-vis, molar conductance and magnetic susceptibility measurements. The general formula of complexes was confirmed as [ML] type [M = Cu(II), Co(II), Zn(II), Ni(II) and VO(II); L = C27H24N4O4]. Magnetic susceptibility, IR and UV-vis, spectral data showed that all the complexes have square planar geometry except vanadyl complex which suggests square pyramidal geometry. Lower molar conductance values proved that all the chelates were non-electrolytic nature. The X-band ESR spectra of [CuL] and [VOL] complexes in DMSO solution suggest that the complexes were predominant covalent character. Powder XRD and SEM image pattern evidenced that all the compounds were crystalline in nature and their size ranges from 100-40 nm. Calf thymus DNA binding potential of [CuL] and [VOL] complexes shows that the binding occurs through intercalation mode with low binding constant. The analgesic, CNS, antiulcer and antimicrobial activities of the investigated compounds report reveals that the chelates were significant effect than free Schiff base.

3,4-Dihydropyrimidin-2(1H)-One Analogues: Microwave irradiated Synthesis with Antimicrobial and Antituberculosis Study

2019 ◽  
Vol 6 (1) ◽  
pp. 61-70
Author(s):  
Navin Patel ◽  
Sabir Pathan ◽  
Hetal I. Soni
Keyword(s):  
Microwave Irradiation ◽  
Biginelli Reaction ◽  
Antitubercular Activity ◽  
Antimicrobial Activities ◽  
Chemical Diversity ◽  
Spectral Studies ◽  
Dilution Method ◽  
Bacterial Strains ◽  
Microwave Irradiation Method

Background: For rapid and sustainable synthesis, microwave irradiation method is serviceable. This present study deals with the preparation of oxadiazole and pyridine bearing 1,2,3,4- tetrahydro pyrimidine derivatives by microwave irradiation. Objective: The present study aims to carry out rapid synthesis of chloro-acetamides of oxadiazoles of Biginelli product and amino cyano derivative of pyridine by microwave-assisted heating. Our efforts are focused on the introduction of chemical diversity in the molecular framework in order to synthesize pharmacologically interesting compounds. Methods:: Microwave irradiation was used for the synthesis of 2-((3-cyano-4-(3,4-dichloro phenyl)- 6-(4-hydroxy-3-methoxyphenyl) pyridin-2-yl) amino)-N-(5-(substituted) -(6-methyl-2-oxo -1,2,3,4- tetrahydro pyrimidin-5-yl)-1,3,4-oxadiazol-2-yl)acetamide by using Biginelli reaction. New structural analogues were confirmed by spectral studies followed by their screening for in vitro antibacterial activity against Staphylococcus aureus, Staphylococcus Pyogenus, Escherichia coli and Pseudomonas aeruginosa bacterial strains and for antifungal activity against Candida albicans, Aspergillus niger and Aspergillus clavatus by micro-broth dilution method. In vitro antimycobacterial activity determined out against (Mycobacterium tuberculosis) H37Rv strain using Lowenstein-Jensen medium. Results: As compared to the conventional method, microwave irradiation method is advantageous for the synthesis of 1,2,3,4-tetrahydropyrimidin derivatives. Potent antimicrobial activities and antitubercular activity were found for some of the compounds. Conclusion: Microwave irradiation method provided an effective way to discover a novel class of antimicrobial and antituberculosis agents. 1,2,3,4-tetrahydropyrimidin derivatives showed improved antimicrobial and good antituberculosis activity.

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