scholarly journals Fast Microwave-Assisted Synthesis of Wells-Dawson-Type 18-Tungsto-2-Phosphate [P2W18O62]6−

Inorganics ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 23 ◽  
Author(s):  
Vamangi Pandya ◽  
Ali Haider ◽  
Hafiz Qasim ◽  
Ali Mougharbel ◽  
Ulrich Kortz ◽  
...  
Keyword(s):  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted ◽  
Synthetic Procedure

We report on a fast microwave-assisted synthetic procedure of the Wells-Dawson-type 18-tungsto-2-phosphate [P2W18O62]6− with a 35% yield in 24 h, rather than a week using conventional heating.

Microwave-assisted Synthesis of Benzoxazoles Derivatives

2020 ◽  
Vol 7 (3) ◽  
pp. 183-195
Author(s):  
Musa Özil ◽  
Emre Menteşe
Keyword(s):  
Microwave Irradiation ◽  
Reaction Medium ◽  
Pharmaceutical Chemistry ◽  
Conventional Heating ◽  
High Yield ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted ◽  
Optical Brighteners ◽  
Chemistry Research ◽  
Extensive Class

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.

scholarly journals Microwave-Assisted Preparation of Luminescent Inorganic Materials: A Fast Route to Light Conversion and Storage Phosphors

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2882
Author(s):  
José Miranda de Carvalho ◽  
Cássio Cardoso Santos Pedroso ◽  
Matheus Salgado de Nichile Saula ◽  
Maria Claudia França Cunha Felinto ◽  
Hermi Felinto de Brito
Keyword(s):  
Rapid Heating ◽  
Inorganic Materials ◽  
Rapid Screening ◽  
Conventional Heating ◽  
Quantum Yields ◽  
Microwave Assisted Synthesis ◽  
Volumetric Heating ◽  
White Leds ◽  
Microwave Assisted ◽  
And Storage

Luminescent inorganic materials are used in several technological applications such as light-emitting displays, white LEDs for illumination, bioimaging, and photodynamic therapy. Usually, inorganic phosphors (e.g., complex oxides, silicates) need high temperatures and, in some cases, specific atmospheres to be formed or to obtain a homogeneous composition. Low ionic diffusion and high melting points of the precursors lead to long processing times in these solid-state syntheses with a cost in energy consumption when conventional heating methods are applied. Microwave-assisted synthesis relies on selective, volumetric heating attributed to the electromagnetic radiation interaction with the matter. The microwave heating allows for rapid heating rates and small temperature gradients yielding homogeneous, well-formed materials swiftly. Luminescent inorganic materials can benefit significantly from the microwave-assisted synthesis for high homogeneity, diverse morphology, and rapid screening of different compositions. The rapid screening allows for fast material investigation, whereas the benefits of enhanced homogeneity include improvement in the optical properties such as quantum yields and storage capacity.

scholarly journals Microwave-Assisted Synthesis of Tetrahydrocarbazole Linked 1,2-Diazoles in Aqueous-Brønsted Acid Catalytic System

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Zubi Sadiq ◽  
Erum Akbar Hussain ◽  
Narjis Naz ◽  
Ambreen Ghani ◽  
Kausar Yasmeen ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Catalytic System ◽  
Multicomponent Reaction ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Spectroscopic Techniques ◽  
Unsaturated Ketones ◽  
Microwave Assisted ◽  
Michael Type Addition

A new series of tetrahydrocarbazole coupled 1,2-diazoles 4/5/6(a–o) in moderate to excellent yield was synthesized successfully via multicomponent reaction approach by adopting Michael type-addition of hydrazines on in situ generated α,β-unsaturated ketones via aldol type strategy under synthetic microwave radiations and conventional heating. Structural confirmations of all the prepared compounds were achieved by spectroscopic techniques. The best results were achieved when equal amounts of water-acetic acid were used in microwave conditions in 4 minutes.

scholarly journals Microwave assisted synthesis of some new coumarin-pyrazoline hybrids and their antimicrobial activity

2015 ◽  
Vol 80 (3) ◽  
pp. 305-313 ◽  
Author(s):  
Dongamanti Ashok ◽  
Bommidi Lakshmi ◽  
Sidda Ravi ◽  
Arram Ganesh
Keyword(s):  
Antimicrobial Activity ◽  
Sodium Acetate ◽  
Pathogenic Bacteria ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Good Activity ◽  
Mass Spectral Data ◽  
Mass Spectral ◽  
Microwave Assisted ◽  
Bacteria And Fungi

A series of pyrazolines 4a-g have been synthesized by Michael addition of chalcones 3a-g with hydrazine hydrate in presence of sodium acetate under conventional heating and microwave irradiation. Structures of the newly synthesized chalcones 3a-g and pyrazolines 4a-g have been established on the basis of IR, 1H & 13C NMR and mass spectral data. All the synthesized compounds were screened for their antimicrobial activity. Some of the compounds shown very good activity compared to standard drugs against all pathogenic bacteria and fungi.

scholarly journals Green, Microwave-Assisted Synthesis of O-Perbutyrylated-Alkyl-Glycosides

Proceedings ◽  
2019 ◽  
Vol 41 (1) ◽  
pp. 42
Author(s):  
Emmanuel Pérez-Escalante ◽  
Luis Guillermo González-Olivares ◽  
Araceli Castañeda-Ovando ◽  
Verónica Salazar-Pereda ◽  
John F. Trant ◽  
...  
Keyword(s):  
Lewis Acids ◽  
Model Compound ◽  
Traditional Approach ◽  
Reaction Times ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Hydroxyl Groups ◽  
Alkyl Glycosides ◽  
Microwave Assisted ◽  
Synthetic Strategy

Chemical synthesis of carbohydrates is a challenging task. Several protection and deprotection steps of hydroxyl groups are required to ensure regioselective formation of the glycosidic bond. Usually, it is achieved through acylation, where conventional heating is combined with addition of Lewis acids as catalysts. This traditional approach has two drawbacks; it is time consuming and often catalysts are hazardous to the environment. An alternative route relies on application of microwaves and/or other Lewis acids with less or no toxicity. Such combination would reduce reaction times and offer a benign synthetic strategy to obtain peracylated compounds. The current work describes an efficient and environmentally mild synthesis of peracylated glycosides with potential application in enzymatic preparation of carbohydrates. Model compound O-perbutyrylated-phenyl-galactose was synthesized using imidazole as catalyst in the microwave-assisted process. The acylation protocol was optimized, and the target sugar was obtained at 50% yield after 1 h. In conclusion, the combination of imidazole and microwaves provides an excellent alternative to swiftly synthesize peracylated glycosides in a benign way.

scholarly journals Microwave-Assisted Synthesis of Arylidene Acetophenones

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Sheauly Khatun ◽  
M. Z. H. Khan ◽  
Khodeza Khatun ◽  
M. A. Sattar
Keyword(s):  
Microwave Irradiation ◽  
Microwave Heating ◽  
Spectral Data ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Efficient Synthesis ◽  
H Nmr ◽  
Microwave Assisted

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.

scholarly journals Microwave assisted synthesis of 2-(2-(tetrazolo[1,5-a]quinolin-4-yl)-2,3-dihydro-1h-benzo[b][1,4]diazepin-4-yl) substituted phenols and evaluation of their antimicrobial activity

2016 ◽  
Vol 81 (8) ◽  
pp. 851-858 ◽  
Author(s):  
Dongamanti Ashok ◽  
Velagapuri Rao ◽  
Rangu Kavitha
Keyword(s):  
Antimicrobial Activity ◽  
Microwave Irradiation ◽  
13C Nmr ◽  
Sodium Acetate ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Substituted Phenols ◽  
Mass Spectral Data ◽  
Mass Spectral ◽  
Microwave Assisted

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.

scholarly journals Antibacterial, Antifungal and Ecotoxic Effects of Ammonium and Imidazolium Ionic Liquids Synthesized in Microwaves

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5181
Author(s):  
Jana Fojtášková ◽  
Ivan Koutník ◽  
Martina Vráblová ◽  
Hana Sezimová ◽  
Milan Maxa ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Alkyl Chain ◽  
Vibrio Fischeri ◽  
Alkyl Chain Length ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Duration Of Action ◽  
Solubility In Water ◽  
Microwave Assisted ◽  
Microwave Reactor

Ionic liquids are increasingly used for their superior properties. Four water-immiscible ionic liquids (butyltriethylammonium bis(trifluoromethylsulfonyl)imide, octyltriethylammonium bis(trifluoromethylsulfonyl)imide, dodecyltriethylammonium bis(trifluoromethylsulfonyl)imide, butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) and their water miscible precursors (bromides) were synthesized in a microwave reactor and by conventional heating. The best conditions for microwave-assisted synthesis concerning the yield and the purity of the product are proposed. The heating in the microwave reactor significantly shortened the reaction time. Biocide and ecotoxic effects of synthesized ionic liquids and their precursors were investigated. All tested compounds had at least a little effect on the growth or living of microorganisms (bacteria or mold). The precursor dodecyltriethylammonium bromide was found to be the strongest biocide, but posed a risk to the aquatic environment due to its relatively high EC50 value in the test with Vibrio fischeri. We assumed that apart from the alkyl chain length, the solubility in water, duration of action, or type of anion can influence the final biocide and ecotoxic effect.

scholarly journals An acceleration of microwave-assisted transesterification of palm oil-based methyl ester into trimethylolpropane ester

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Nur Atiqah Mohamad Aziz ◽  
Robiah Yunus ◽  
Hamidah Abd Hamid ◽  
Alsultan Abdul Kareem Ghassan ◽  
Rozita Omar ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Microwave Irradiation ◽  
Palm Oil ◽  
Energy Requirement ◽  
Reaction System ◽  
Conventional Heating ◽  
Molar Ratio ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted ◽  
Sodium Methoxide Solution

AbstractMicrowave-assisted synthesis is known to accelerate the transesterification process and address the issues associated with the conventional thermal process, such as the processing time and the energy input requirement. Herein, the effect of microwave irradiation on the transesterification of palm oil methyl ester (PME) with trimethylolpropane (TMP) was evaluated. The reaction system was investigated through five process parameters, which were reaction temperature, catalyst, time, molar ratio of TMP to PME and vacuum pressure. The yield of TMP triester at 66.9 wt.% and undesirable fatty soap at 17.4% were obtained at 130 °C, 10 mbar, sodium methoxide solution at 0.6 wt.%, 10 min reaction time and molar ratio of TMP to PME at 1:4. The transesterification of palm oil-based methyl ester to trimethylolpropane ester was 3.1 folds faster in the presence of microwave irradiation. The total energy requirement was markedly reduced as compared to the conventional heating method. The findings indicate that microwave-assisted transesterification could probably be an answer to the quest for a cheaper biodegradable biolubricant.

scholarly journals Microwave-assisted synthesis and antimicrobial evaluation of 6-[3-aryl-1-phenyl-4’,5’-dihydro[4,5’-bi-1H-pyrazol]-3’-yl]-2H-chromen-5-ols

2019 ◽  
Vol 84 (3) ◽  
pp. 237-244
Author(s):  
Dongamanti Ashok ◽  
Rangu Kavitha ◽  
Srinivas Gundu ◽  
Madderla Sarasija
Keyword(s):  
Antimicrobial Activity ◽  
Microwave Irradiation ◽  
Sodium Acetate ◽  
Analytical Data ◽  
Conventional Heating ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted ◽  
Structural Assignment ◽  
Antimicrobial Evaluation ◽  
Antimicrobial Potency

A new series of 6-[3-aryl-1-phenyl-4?,5?-dihydro[4,5?-bi-1H-pyrazol]-3?-yl]-2H-chromen-5-ol derivatives was synthesized by Michael addition of chalcones 5a?j with hydrazine hydrate in presence of sodium acetate under conventional heating and microwave irradiation. Structural assignment of the products was confirmed based on IR, 1H-NMR, 13C-NMR, MS and analytical data. All the synthesized compounds 6a?j were screened for their antimicrobial activity against various bacterial and fungal strains. Most of the compounds exhibited variable range of antimicrobial activity and compounds 6c?f and 6i showed promising antimicrobial potency.

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