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

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.

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Regioselective Synthesis of Potent 4,5,6,7-Tetrahydroindazole Derivatives via Microwave-assisted Vilsmeier-Haack Reaction and their Antioxidant Activity Evaluation

Letters in Organic Chemistry ◽

10.2174/1570178615666180919120329 ◽

2019 ◽

Vol 16 (3) ◽

pp. 194-201 ◽

Cited By ~ 2

Author(s):

Renu Bala ◽

Vandana Devi ◽

Pratibha Singh ◽

Navjot Kaur ◽

Pawandeep Kaur ◽

...

Keyword(s):

Antioxidant Activity ◽

Microwave Irradiation ◽

Biological Activities ◽

Reaction Times ◽

Conventional Heating ◽

High Chemical ◽

Microwave Assisted ◽

Work Up ◽

Active Methylene ◽

By Products

Background: Tetrahydroindazole, a member of the fused-pyrazole system, is a least studied class of heterocyclic compounds owing to its scarcity in nature. However, a large number of synthetically prepared tetrahydroindazoles are known to show a variety of biological activities such as interleukin- 2 inducible T-Cell kinase inhibitors, AMPA receptor positive allosteric modulators, antitumor, antituberculosis, anti-inflammatory and antimicrobial activities. Vilsmeier-Haack reaction is one of the most important chemical reactions used for formylation of electron rich arenes. Even though Vilsmeier- Haack reaction was studied on a wide variety of hydrazones derived from active methylene compounds, literature lacks the examples of the use of 4-substituted cyclohexanones as a substrate for the synthesis of 4,5,6,7-tetrahydroindazoles. The study of the reaction of Vilsmeier-Haack reagent with hydrazones derived from cyclic keto compounds having active methylene has been considered the interested topic of investigation. In the present study, ethyl cyclohexanone-4-carboxylate was treated with one equivalent of various hydrazines for two hours and the resulted hydrazones were further treated with an OPC-VH reagent (Vilsmeier-Haack reagent isolated from phthaloyl dichloride and N,Ndimethylformamide) afforded 4,5,6,7-tetrahydroindazoles in excellent yields. The synthesized compounds 4a-f and 5a-f were screened for their antioxidant activities using the DPPH radical scavenging assay. The target compounds were synthesized regioselectively using 4+1 approach in excellent yields. A number of experiments using both conventional heating as well as microwave irradiation methods were tried and on comparison, microwave irradiation method was found excellent in terms of easy work up, high chemical yields, shortened reaction times, clean and, no by-products formation. Some of the synthesized compounds showed significant antioxidant activity. The microwave assisted synthesis of 4,5,6,7-tetrahydroindazoles from ethyl cyclohexanone-4-carboxylate has been reported under mild conditions in excellent yield. Easy work up, high chemical yield, shortened reaction times, clean and no by-products formation are the major advantages of this protocol. These advantages may make this method useful for chemists who are interested in developing novel 4,5,6,7-tetrahydroindazole based drugs.

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Microwave-assisted Synthesis of Benzoxazoles Derivatives

Current Microwave Chemistry ◽

10.2174/2213335607999200518094114 ◽

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.

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

Molecules ◽

10.3390/molecules26102882 ◽

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.

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Microwave-assisted synthesis of zinc 5-(4-carboxyphenyl)-10,15,20-triphenylporphyrin and zinc 5-(4-carboxyphenyl)-10,15,20-triphenylchlorin

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424614500953 ◽

2015 ◽

Vol 19 (04) ◽

pp. 595-600 ◽

Cited By ~ 5

Author(s):

Rima Chouikrat ◽

Aymeric Champion ◽

Régis Vanderesse ◽

Céline Frochot ◽

Albert Moussaron

Keyword(s):

Reaction Times ◽

Microwave Assisted Synthesis ◽

Spectroscopic Techniques ◽

H Nmr ◽

Microwave Assisted ◽

Experimental Protocols ◽

Time Of Reaction

The microwave-assisted synthesis of zinc 5-(4-carboxyphenyl)-10,15,20-triphenylporphyrin and zinc 5-(4-carboxyphenyl)-10,15,20-triphenylchlrorin are described and compared to classic conditions of synthesis in terms of time of reaction and yields obtained. The new experimental protocols are easy to implement required small amounts of reagents and solvents and lead to short reaction times. All compounds have been characterized by 1 H NMR, MS and spectroscopic techniques.

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MICROWAVE-ASSISTED SYNTHESIS OF ALKYL GLYCOSIDES

Synthetic Communications ◽

10.1081/scc-100104035 ◽

2001 ◽

Vol 31 (9) ◽

pp. 1277-1283 ◽

Cited By ~ 23

Author(s):

Matthias Nüchter ◽

Bernd Ondruschka ◽

Werner Lautenschläger

Keyword(s):

Microwave Assisted Synthesis ◽

Alkyl Glycosides ◽

Microwave Assisted

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Green Chemistry Approach for Efficient Synthesis of Schiff Bases of Isatin Derivatives and Evaluation of Their Antibacterial Activities

Journal of Nanoparticles ◽

10.1155/2013/549502 ◽

2013 ◽

Vol 2013 ◽

pp. 1-5 ◽

Cited By ~ 4

Author(s):

Jnyanaranjan Panda ◽

V. Jagannath Patro ◽

Biswa Mohan Sahoo ◽

Jitendriya Mishra

Keyword(s):

Green Chemistry ◽

Schiff Bases ◽

Reaction Times ◽

Antibacterial Activities ◽

Primary Amines ◽

Microwave Assisted Synthesis ◽

Azomethine Group ◽

Microwave Assisted ◽

Isatin Derivatives

Microwave-assisted organic synthesis, a green chemistry approach, is nowadays widely used in the drug synthesis. Microwave-assisted synthesis improves both throughput and turnaround time for medicinal chemists by offering the benefits of drastically reduced reaction times, increased yields, and pure products. Schiff bases are the important class of organic compounds due to their flexibility, and structural diversities due to the presence of azomethine group which is helpful for elucidating the mechanism of transformation and rasemination reaction in biological system. This novel compound could also act as valuable ligands for the development of new chemical entities. In the present work, some Schiff bases of Isatin derivatives was synthesized using microwave heating method. Schiff base of Isatin were synthesized by condensation of the keto group of Isatin with different aromatic primary amines. They were characterized by means of spectral data and subsequently subjected to the in vitro antibacterial activities against gram positive and gram negative strains of microbes. It was observed that the compound with electron withdrawing substituents exhibited good antibacterial activities against almost all the micro organisms.

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

Journal of Chemistry ◽

10.1155/2017/3902751 ◽

2017 ◽

Vol 2017 ◽

pp. 1-17 ◽

Cited By ~ 1

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.

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Rapid microwave-assisted synthesis of hybrid zeolitic–imidazolate frameworks with mixed metals and mixed linkers

Journal of Materials Chemistry A ◽

10.1039/c6ta11170j ◽

2017 ◽

Vol 5 (13) ◽

pp. 6090-6099 ◽

Cited By ~ 72

Author(s):

Febrian Hillman ◽

John M. Zimmerman ◽

Seung-Min Paek ◽

Mohamad R. A. Hamid ◽

Woo Taik Lim ◽

...

Keyword(s):

Microwave Assisted Synthesis ◽

Zeolitic Imidazolate Frameworks ◽

Metal Centers ◽

Mixed Metal ◽

Microwave Assisted ◽

Synthetic Strategy

Herein we report a new microwave-assisted synthetic strategy to rapidly prepare hybrid zeolitic–imidazolate frameworks (ZIFs): ZIFs with mixed metal centers and/or mixed linkers.

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Microwave Assisted Synthesis of Six Member Ring Azaheterocycles and Their Antimycobacterial and Anticancer Evaluation

Revista de Chimie ◽

10.37358/rc.20.3.7999 ◽

2001 ◽

Vol 71 (3) ◽

pp. 287-293 ◽

Cited By ~ 1

Author(s):

Cristina Al Matarneh ◽

Catalina-Ionica Ciobanu ◽

Violeta Mangalagiu ◽

Gheorghita Zbancioc ◽

Ramona Danac

Keyword(s):

Breast Cancer ◽

Prostate Cancer ◽

Lung Cancer ◽

Renal Cancer ◽

Reaction Times ◽

Antimycobacterial Activity ◽

Microwave Assisted Synthesis ◽

Thermal Heating ◽

Microwave Assisted ◽

Mw Irradiation

We report herein a comparative study concerning the influence of microwave (MW) irradiation comparative with conventional thermal heating (TH) in the reaction of six member ring azaheterocycles (derived from phenanthroline, quinoline, isoquinoline and phthalazine) with ethyl cyanoformate, and their anticancer and antimycobacterial activity. Under MW irradiation the reactions have some undeniable advantages: the reaction times decrease dramatically (from hours to minutes), the yields are higher, the reactions became selective in some cases (4,7-phenanthrolinium and phthalazinium ylides). The decreasing of reaction time+ from hours to minutes corroborated with the fact that in majority of cases the yield are higher and the selectivity is better, allow us to say that these reactions could be considered as eco-friendly. As far for biological activity, three of the compounds exhibited a significant antitumor activity against some cancer cell lines including prostate cancer, leukemia, renal cancer, lung cancer and breast cancer. The best potency in terms of growth inhibition of tumor cells (~45%) was shown by compound 4a against renal cancer A498 and ovarian cancer SK-OV-3 cells. The tested compounds have not shown any antimycobacterial activity against Mycobacterium tuberculosis.

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

Inorganics ◽

10.3390/inorganics7020023 ◽

2019 ◽

Vol 7 (2) ◽

pp. 23 ◽

Cited By ~ 1

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.

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