scholarly journals Microwave-Assisted Synthesis of Some Quinoxaline-Incorporated Schiff Bases and Their Biological Evaluation

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
L. Achutha ◽  
R. Parameshwar ◽  
B. Madhava Reddy ◽  
V. Harinadha Babu

Quinoxaline-incorporated Schiff bases(4a–j)were synthesized by the condensation of 2-[(3-methylquinoxalin-2-yl)oxy]acetohydrazide(3)with indole-3-carbaldehyde, furfuraldehyde, 5-(4-nitrophenyl)-2-furfuraldehyde, and substituted benzaldehydes under conventional and microwave irradiation methods. The microwave method was found to be remarkably successful with higher yields, less reaction time, and environmentally friendly compared to conventional heating method. The chemical structures of the synthesized compounds have been confirmed by analytical and spectral data. All the compounds have been evaluated for antitubercular and anti-inflammatory activities.

2018 ◽  
Vol 18 (1) ◽  
pp. 53
Author(s):  
Ratnaningsih Eko Sardjono ◽  
Iqbal Musthapa ◽  
Iis Rosliana ◽  
Fitri Khoerunnisa ◽  
Galuh Yuliani

A new versatile macromolecule cyclic C-3,7-dimethyl-7-hydroxycalix[4]resorcinarene (CDHHK4R) has been synthesized from a fragrance agent, 7-hydroxycitronellal, via microwave irradiation. The reaction utilized a domestic microwave oven at various irradiation time and power to yield an optimum condition. As a comparison, the conventional heating method was also employed for the synthesis of the same calix[4]resorcinarene. Compared to the conventional method, microwave-assisted reaction effectively reduced the reaction time, the amount of energy consumption and the waste production. It is found that the synthesis of CDHHK4R by microwave irradiation yielded 77.55% of product, higher than by conventional heating which was only 62.17%.


2020 ◽  
Vol 7 (3) ◽  
pp. 183-195
Author(s):  
Musa Özil ◽  
Emre Menteşe

Background: Benzoxazole, containing a 1,3-oxazole system fused with a benzene ring, has a profound effect on medicinal chemistry research owing to its important pharmacological activities. On the other hand, the benzoxazole derivative has exhibited important properties in material science. Especially in recent years, microwave-assisted synthesis is a technique that can be used to increase diversity and quick research in modern chemistry. The utilization of microwave irradiation is beneficial for the synthesis of benzoxazole in recent years. In this focused review, we provide a metaanalysis of studies on benzoxazole in different reaction conditions, catalysts, and starting materials by microwave technique so far, which is different from conventional heating. Methods: Synthesis of different kind of benzoxazole derivatives have been carried out by microwave irradiation. The most used method to obtain benzoxazoles is the condensation of 2-aminophenol or its derivatives with aldehydes, carboxylic acids, nitriles, isocyanates, and aliphatic amines. Results: Benzoxazole system and its derivatives have exhibited a broad range of pharmacological properties. Thus, many scientists have remarked on the importance of the synthesis of different benzoxazole derivatives. Conventional heating is a relatively inefficient and slow method to convey energy in orientation to the reaction medium. However, the microwave-assisted heating technique is a more effective interior heating by straight coupling of microwave energy with the molecules. Conclusion: In this review, different studies were presented on the recent details accessible in the microwave- assisted techniques on the synthesis of the benzoxazole ring. It presents all examples of such compounds that have been reported from 1996 to the present. Benzoxazoles showed an extensive class of chemical substances not only in pharmaceutical chemistry but also in dyestuff, polymer industries, agrochemical, and optical brighteners. Thus the development of fast and efficient achievement of benzoxazoles with a diversity of substituents in high yield is getting more noteworthy. As shown in this review, microwave-assisted synthesis of benzoxazoles is a very effective and useful technique.


2019 ◽  
Vol 31 (5) ◽  
pp. 993-996 ◽  
Author(s):  
Sanjay S. Kotalwar ◽  
Amol D. Kale ◽  
Ram B. Kohire ◽  
Vasant B. Jagrut

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.


Synlett ◽  
2019 ◽  
Vol 30 (05) ◽  
pp. 563-566 ◽  
Author(s):  
Sylvestre Toumieux ◽  
Mohamad Khodadadi ◽  
Gwladys Pourceau ◽  
Matthieu Becuwe ◽  
Anne Wadouachi

The first copper-catalyzed aziridination of olefins using re­cyclable magnetic nanoparticles is described. Magnetic nanoparticles were modified with dopamine and used as a support to coordinate copper. The methodology was optimized with styrene as olefin and using [N-(p-toluenesulfonyl)imino]phenyliodinane (PhI=NTs) as nitrene source. A microwave irradiation decreased the reaction time by 4-fold compared to conventional heating method. The catalyst was recovered by simple magnetic extraction and could be reused successfully up to five times without significant loss of activity. The methodology was ­applied to a range of different olefins leading to moderate to excellent yields in the formation of the expected aziridine.


2005 ◽  
Vol 09 (03) ◽  
pp. 163-169 ◽  
Author(s):  
Farzad Bahadoran ◽  
Solmaz Dialameh

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.


2012 ◽  
Vol 268-270 ◽  
pp. 500-503
Author(s):  
Jun De Xing ◽  
Zhi Liu ◽  
Zhao Yu Zhang ◽  
Xiao Fei Jia

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.


2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Sheauly Khatun ◽  
M. Z. H. Khan ◽  
Khodeza Khatun ◽  
M. A. Sattar

An efficient synthesis of arylidene acetophenones have been achieved by using the microwave heating in comparison to the conventional heating. In this work compound 1-phenyle-3-(4-droxyphenyle)-2-propen-1-one, 1-(4-chlorophenyle)-3-phenyle-2-propen-1-one, and 1-(4-chlorophenyle)-3-(4-hydroxyphenyle)-2-propen-1-one have been synthesized by the condensation reaction between aromatic aldehydes and substituted acetophenones under microwave irradiation. The compounds of aldehydes and acetophenones were used as benzaldehyde, parahydroxybenzaldehyde, acetophenone, and parachloroacetophenone. The result shows that the time taken for the reaction was reduced from the conventional 1-2 hours to 60–120 seconds. The yield of the compounds in the conventional heating was moderate while the highest yield of 90–98% was observed in MWI method. The structure of the compounds was characterized by their IR,1H-NMR spectral data.


2016 ◽  
Vol 22 (6) ◽  
Author(s):  
Dongamanti Ashok ◽  
Rayagiri Suneel Kumar ◽  
Devulapally Mohan Gandhi ◽  
Madderla Sarasija ◽  
Anireddy Jayashree ◽  
...  

AbstractA series of novel chroman-4-one fused benzofurans were synthesized by cyclization of the corresponding chalcones under microwave irradiation. All new compounds were characterized by IR,


2016 ◽  
Vol 81 (8) ◽  
pp. 851-858 ◽  
Author(s):  
Dongamanti Ashok ◽  
Velagapuri Rao ◽  
Rangu Kavitha

A series of new benzodiazepines 4a-h have been synthesized by Michael addition of chalcones 3a-h with o-phenylenediamine (OPDA) in presence of sodium acetate under conventional heating and microwave irradiation. Structures of the newly synthesized benzodiazepines 4a-h have been established on the basis of IR, 1H & 13C NMR and mass spectral data and tested for antimicrobial activity.


2021 ◽  
Vol 08 ◽  
Author(s):  
Monika R. Tiwari ◽  
Navin B. Patel

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.


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