scholarly journals Comparative studies on conventional and microwave-assisted synthesis of a series of 2,4-di and 2,3,4-trisubstituted benzimidazo[1,2-a] pyrimidines and their antimicrobial activities

2009 ◽  
Vol 7 (3) ◽  
pp. 337-342 ◽  
Author(s):  
Oztekin Algul ◽  
Asiye Meric ◽  
Serpil Polat ◽  
N. Didem Yuksek ◽  
Mehmet Serin
Keyword(s):  
Reaction Time ◽  
Microwave Irradiation ◽  
Comparative Studies ◽  
Antimicrobial Activities ◽  
Microwave Assisted Synthesis ◽  
Microwave Irradiation Method ◽  
Yield Increase ◽  
Microwave Assisted ◽  
Mic Value

AbstractComparative studies were performed on a series of 2,4-di and 2,3,4-trisubstituted benzimidazo[1,2-a]pyrimidines, which were synthesized with conventional and microwave heating methods. In microwave irradiation method, approximately, 95–97.5% of the reaction time was increased and 1–45% yield increase was obtained. All compounds were able to inhibit the growth of the screened microorganisms in vitro with MIC values between 3.9–250 μg mL−1. The highest activity was expressed by compound IIId (2,4-diphenyl-benzo[4,5]imidazo[1,2-a] pyrimidine), which has the MIC value of 3.9 μg mL−1 and 31.2 μg mL-1 for Penicillium natatum ATCC 24791 and E. faecalis ATCC 29212, respectively.

Microwave assisted Synthesis and Biological activities of 9-boronobenzyladenine derivatives

2007 ◽  
Vol 2007 (6) ◽  
pp. 347-349 ◽  
Author(s):  
Xue-Jun Yu ◽  
Wei Liu ◽  
Wei-Dong Hu ◽  
Xue-Liang Dong ◽  
Dan Xu ◽  
...  
Keyword(s):  
Reaction Time ◽  
Microwave Irradiation ◽  
Biological Activities ◽  
Microwave Assisted Synthesis ◽  
Thermal Methods ◽  
Microwave Assisted ◽  
Pharmacological Tests

Microwave enhanced syntheses of 9-boronobenzyladenine derivatives by the reaction of adenine with the corresponding bromomethylphenylboric acid were reported. Microwave irradiation reduced the overnight reaction time of conventional thermal methods to 10 min, provided the desired products and increased the yields up to three times. Preliminary in vitro pharmacological tests were also described.

scholarly journals Microwave Assisted Synthesis of 1,5-Benzothiazepines Using Greener Reaction Medium

2019 ◽  
Vol 31 (5) ◽  
pp. 993-996 ◽  
Author(s):  
Sanjay S. Kotalwar ◽  
Amol D. Kale ◽  
Ram B. Kohire ◽  
Vasant B. Jagrut
Keyword(s):  
Reaction Time ◽  
Microwave Irradiation ◽  
Reaction Medium ◽  
Microwave Assisted Synthesis ◽  
Reaction Conditions ◽  
Renewable Sources ◽  
Microwave Assisted ◽  
High Yields

An efficient and eco-friendly synthesis of 1,5-benzothiazepines has been developed by the reaction of various 2-propen-1-ones with 2-aminothiophenol using microwave irradiation in greener reaction medium, glycerol. The clean reaction conditions, shorter reaction time, high yields and non-toxic, biodegradable reaction medium manufactured from renewable sources are unique features of this method.

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.

Microwave assisted synthesis of substituted metallophthalocyanines and their catalytic activity in epoxidation reaction

2005 ◽  
Vol 09 (03) ◽  
pp. 163-169 ◽  
Author(s):  
Farzad Bahadoran ◽  
Solmaz Dialameh
Keyword(s):  
Catalytic Activity ◽  
Reaction Time ◽  
Microwave Irradiation ◽  
Microwave Assisted Synthesis ◽  
Free Condition ◽  
Catalytic Activities ◽  
Microwave Assisted ◽  
Solvent Free Condition ◽  
Epoxidation Reaction ◽  
Phthalocyanine Ring

Substituted iron and cobalt phthalocyanines are easily prepared by microwave irradiation of the starting materials under solvent free condition, which reduced reaction time considerably. The synthesized metallophthalocyanines (octachloro-, tetranitro-, tetracarboxy- or polyphthalocyanine) are used as epoxidation catalysts of cyclooctene in homogeneous and heterogeneous conditions by iodosylbenzene as an oxidant. Their catalytic activities have shown that the electron withdrawing groups on the phthalocyanine ring have a very small effect on stability of the catalyst during the reactions.

scholarly journals Microwave assisted synthesis and antimicrobial activity of some novel pyrimidine derivatives

2007 ◽  
Vol 72 (2) ◽  
pp. 109-117 ◽  
Author(s):  
S.J. Vaghasia ◽  
V.H. Shah
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Activities ◽  
Microwave Assisted Synthesis ◽  
Mass Spectral Data ◽  
Pyrimidine Derivatives ◽  
Plate Method ◽  
Mass Spectral ◽  
Microwave Assisted ◽  
New Compounds

The synthesis of thiazolo[5,4-d]pyrimidines can be achieved from different 5- thiazolidinones, 2-butyl-1H-imidazole-5-carbaldehyde and thiourea using microwave irradiation within 5 min. The structures of the products were supported by FTIR, PMR and mass spectral data. The in vitro antimicrobial activity of the synthesized thiazolo[5,4-d]pyrimidines 1a-j, having substituents at the 1- and 3-positions, were determined by the cup-plate method against several standard strains chosen to define the spectrum and potency of the new compounds. The antimicrobial activities of the thiazolo[5,4-d]pyrimidines 1a-j are compared with those of known chosen standard drugs, viz. ampicillin, chloramphenicol, ciprofloxacin, norfloxacin and griseofulvin. .

Microwave-Assisted Synthesis of 2-(2-Nitroethenly)thiophene from 2-Thiophenecarboxaldehyde and Nitromethane

2012 ◽  
Vol 268-270 ◽  
pp. 500-503
Author(s):  
Jun De Xing ◽  
Zhi Liu ◽  
Zhao Yu Zhang ◽  
Xiao Fei Jia
Keyword(s):  
Energy Source ◽  
Reaction Time ◽  
Microwave Irradiation ◽  
Knoevenagel Condensation ◽  
Microwave Assisted Synthesis ◽  
Beta Alanine ◽  
Microwave Assisted ◽  
Reaction Condition ◽  
Efficient Access

2-(2-Nitroethenly)thiophene can be obtained from 2-thiophenecarboxaldehyde and nitromethane under Knoevenagel condensation conditions. We used beta-alanine as a catalyst and microwave irradiation as the energy source. Different reaction condition, such as beta-alanine consumption and reaction time were studied. The results indicate that the application of microwave irradiation increases the yield of desired compound. beta-Alanine-catalyzed activation of 2-thiophenecarboxaldehyde provides an efficient access to 2-(2-nitroethenly)thiophene with reusability of the catalyst.

Synthesis and Pharmacological activities of Oxadiazole and Pyrimidine bearing Thiocoumarin derivatives

2021 ◽  
Vol 08 ◽  
Author(s):  
Monika R. Tiwari ◽  
Navin B. Patel
Keyword(s):  
Reaction Time ◽  
Microwave Irradiation ◽  
Simple Procedure ◽  
Radical Scavenging ◽  
Ring System ◽  
Microwave Assisted Synthesis ◽  
Synthetic Approach ◽  
Pharmacological Activities ◽  
Microwave Assisted ◽  
Anti Oxidant

Aims: The study aims to synthesize thiocoumarin scaffolds clubbed with pyrimidine and 1,3,4-oxadiazole ring system under microwave irradiation and describes their pharmacological activities. Background: We report herein a Lewis acid catalyzed efficient and simple procedure for synthesis of novel series of thiocoumarin clubbed with pyrimidine and 1,3,4-oxadiazole motifs under microwave irradiation. The microwave assisted technique has many advantages such as higher yield, a clean and selective procedure, shorter reaction time and simple work-up. Objective: The objective of the present study is to design and synthesize thiocoumarin scaffolds clubbed with pyrimidine and 1,3,4-oxadiazole ring system by microwave-assisted heating. Our prime focus is to highlight synthetic approach developed for the synthesis of heterocyclic moieties of pharmacological interest and the prominence has also been given to distinct advantages provided by microwave heating. Methods: Thiocoumarin clubbed with pyrimidine and 1,3,4-oxadiazole motifs was synthesized under microwave irradiation. All the synthesized molecules were evicted by IR, 1H NMR, 13C NMR and Mass spectra. The antimicrobial activity of synthesized compounds was examined against two Gram-negative bacteria (E. coli, P. aeruginosa), two Gram-positive bacteria (S. aureus, S. pyogenes) and three fungi (C. albicans, A. niger, A. clavatus) using the MIC (Minimal Inhibitory Concentration) method, anti-tubercular activity H37Rv using L. J. Slope Method and anti-oxidant activity using DPPH and ABTS bioassay method. Results: The application of microwave technology to rapid synthesis of biologically significant thiocoumarin analogues is very promising because of its shorter reaction time and higher yield. Some of these new derivatives showed moderate to good in-vitro anti-bacterial, anti-fungal and anti-tubercular activity. Compounds B4 and B7 appeared to have high radical scavenging efficacies as 35.32 ± 0.446 and 33.97 ± 1.069 μg/mL ± SD of IC50 values in DPPH and ABTS bioassay, respectively. Conclusion: Microwave assisted synthesis provides an implicit way to discover promising class of molecular entities for the development of new anti-microbial and anti-oxidant agents. Oxadiazole and Pyrimidine bearing Thiocoumarin derivatives showed improved anti-microbial, anti-tubercular and anti-oxidant activity.

scholarly journals Microwave-Assisted Synthesis of 2-(5-(5-(4-Substituted phenyl)-2-(5-methoxy- 2H-chromen-3-yl)-1H-imidazol-1-yl)alkyl)-1H-benzo[de]isoquinoline- 1,3(2H)-dione Derivatives and their Antimicrobial Activity

2020 ◽  
Vol 32 (4) ◽  
pp. 839-844
Author(s):  
D. Ashok ◽  
K. Ramakrishna ◽  
Nalaparaju. Nagaraju ◽  
Ravinder Dharavath ◽  
M. Ram Reddy ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Microwave Irradiation ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Klebsiella Pneumonia ◽  
Green Solvents ◽  
Microwave Irradiation Method ◽  
Reaction Conditions ◽  
Mass Spectral

A method for the synthesis of several imidazoles containing isoquinoline scaffolds under conventional and microwave irradiation methods. In the microwave irradiation method gives higher yields with in shorter reaction time as compared to conventional heating method, using green solvents and eco-friendly reaction conditions. All the synthesized derivatives were characterized by IR, NMR and Mass spectral analysis. Furthermore, the title compounds were screened for their in vitro antimicrobial activity against bacteria such as Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Klebsiella pneumonia as well as fungi such as Aspergillus niger, Aspergillus flavus and Fusarium oxysporum. The compounds 8a, 8d, 8e and 8h exhibited better antimicrobial activity against all organisms.

Microwave Assisted Synthesis of Isoquercitrin Using Enzymatic Hydrolysis of Rutin

2014 ◽  
Vol 1033-1034 ◽  
pp. 311-314 ◽  
Author(s):  
Jun Wang ◽  
Guo Xia Sun ◽  
An Gong ◽  
Xiang Yang Wu
Keyword(s):  
Reaction Time ◽  
Enzymatic Hydrolysis ◽  
Microwave Irradiation ◽  
Microwave Assisted Synthesis ◽  
Rapid Synthesis ◽  
Reaction Efficiency ◽  
Microwave Assisted ◽  
Hydrolysis Of

A novel and rapid synthesis of isoquercitrin using enzymatic hydrolysis of rutin under microwave irradiation was investigated. In the [Bmim][BF4]-buffer (pH 9.0) system under microwave irradiation, rutin conversion, isoquercitrin yield and quercetin yield were 89.18%, 84.74% and 2.79%, respectively, in conditions of 5 min and 30 °C. The preparation cost of isoquercitrin was significantly reduced by decreasing reaction time (from 10 h to 5 min) and increasing reaction efficiency (by 120 times).

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