scholarly journals Fast synthesis of a tris(N,N-diimine)chromium(iii) complex by a microwave-assisted approach

RSC Advances ◽  
2014 ◽  
Vol 4 (30) ◽  
pp. 15507-15510 ◽  
Author(s):  
M. Jazmín Silvero ◽  
Walter José Peláez ◽  
Pablo F. Garcia ◽  
Gerardo A. Argüello

This article describes a quick, easy and eco-friendly procedure to synthesize [Cr(biim)3](NO3)3 by employing microwave irradiation.

2011 ◽  
Vol 9 (4) ◽  
pp. 557-566 ◽  
Author(s):  
M. Teresa Barros ◽  
Ana Mouquinho ◽  
Krasimira Petrova ◽  
Mara Saavedra ◽  
João Sotomayor

AbstractIt has been reported that the length of the molecular chain and the rigidity of molecules influence the structure of the polymer network in PDLC films and hence the electro-optical properties of the composites. Herein, a series of new aromatic monomeric monomethacrylates, bismethacrylates and monovinylbenzene derivatives with a mesogenic core were successfully synthesized under microwave irradiation. The microwave assisted synthesis resulted in decreased reaction times, reduced solvent requirement, increased operational simplicity, and in most cases, improved yields and selectivity.


2005 ◽  
Vol 2005 (4) ◽  
pp. 245-247 ◽  
Author(s):  
Radhika S Kusurkar ◽  
Shailesh K. Goswami ◽  
Mahadev B. Talawar ◽  
Girish M. Gore ◽  
Shri N. Asthana

This paper reports the first microwave-assisted synthesis of diaminoglyoxime (DAG) and diaminofurazan (DAF). The synthesis involved the vicarious nucleophilic substitution of H of glyoxime using hydroxylamine hydrochloride under microwave irradiation for 2 to 3 min to obtain DAG, which on further irradiation in alkali solution for 20 min yielded DAF. Conversion of glyoxime into DAF was also achieved in a one pot sequence in good overall yield using microwave irradiation.


2019 ◽  
Vol 16 (3) ◽  
pp. 194-201 ◽  
Author(s):  
Renu Bala ◽  
Vandana Devi ◽  
Pratibha Singh ◽  
Navjot Kaur ◽  
Pawandeep Kaur ◽  
...  

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.


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.


2020 ◽  
Vol 3 (1) ◽  
pp. 27
Author(s):  
Raúl Eduardo Gordillo-Cruz ◽  
Liliana Gonzalez-Reyes ◽  
Milton Coporo-Reyes ◽  
Nieves Zavala-Segovia ◽  
Bernardo A. Frontana-Uribe ◽  
...  

An array of 2,4-disubstituted thiazolines was obtained through Asinger reaction approach from the straightforward treatment of diverse aldehydes/ketones with 1-mercaptopropan-2-one, in the presence of NH3 assisted by microwave irradiation, displaying similar and sometimes higher yields, as well as shorter reaction times that traditional Asinger reaction conditions at room and lower temperatures.


1999 ◽  
Vol 23 (2) ◽  
pp. 118-119
Author(s):  
Vaishali Chakraborty ◽  
Manobjyoti Bordoloi

An efficient and mild methodology for the oxidation of alcohols to the corresponding carbonyl functions is described using pyridinium chlorochromate under microwave irradiation.


Synthesis ◽  
2021 ◽  
Author(s):  
Muhammad Syafiq Bin Shahari ◽  
Ahmad Junaid ◽  
Edward R. T. Tiekink ◽  
Anton V. Dolzhenko

A new method for the fast synthesis of diverse 4-aryl-6-cycloamino-1,3,5-triazin-2-amines was developed. The synthesis is performed under microwave irradiation in a one-pot manner from cyanoguanidine, aromatic aldehydes, and cyclic amines. Their three-component reaction in the presence of hydrochloric acid produced dihydrotriazines, which were then converted (without isolation) to the targeted compounds via aromatic dehydrogenation in the presence of alkali. The reaction tolerated various aromatic aldehydes (including heterocyclic) and cyclic amines. Crystal structures of two representative 4-aryl-6-morpholino-1,3,5-triazin-2-amines were established by X-ray crystallography. The results of preliminary biological screening identified potent antileukemic activity for 6-(3,4-dihydroisoquinolin-2(1<i>H</i>)-yl)-4-phenyl-1,3,5-triazin-2-amine.


2011 ◽  
Vol 197-198 ◽  
pp. 417-420 ◽  
Author(s):  
Shu Cai Zhou ◽  
Chen Guang Bai ◽  
Chun Lin Fu

In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg2Sil-xSnxsolid solutions, Mg2Sil-xSnxsolid solutions have been prepared by Microwave-assisted Synthesis techniques. The heating behavior of Mg, Si and Sn fixed powder was investigated under microwave irradiation. X-ray diffraction (XRD) was used to characterize the powders. The results suggest that the temperature-rising rate is also dependent on the initial green density and higher green density provides lower heating rate while power setting are fixed. XRD patterns show that Mg2Sil-xSnxsolid solutions have been well formed under microwave irradiation.


2005 ◽  
Vol 2005 (1) ◽  
pp. 27-28 ◽  
Author(s):  
Jaime Charris ◽  
Arthur Barazarte ◽  
José Domínguez ◽  
Neira Gamboa

A rapid method for the preparation of N-aryl-2-methylthio-4-oxo-1,4-dihydro quinoline-3-carbonitriles (2a–e) and N-aryl-3-methylthio-4H-1,4-benzothiazine-2-carbonitrile 1,1-dioxides (2f–o) is reported. The cyclization is accelerated by microwave irradiation under solvent free conditions in the presence of K2CO3.


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