Developments in Microwave-Assisted Organic Chemistry

1995 ◽  
Vol 48 (10) ◽  
pp. 1665 ◽  
Author(s):  
CR Strauss ◽  
RW Trainor
Keyword(s):  
Organic Chemistry ◽  
Organic Synthesis ◽  
Batch Reactor ◽  
Environmentally Benign ◽  
Safety Issues ◽  
Microwave Assisted ◽  
Heating And Cooling ◽  
Microwave Reactor ◽  
Microwave Reactors ◽  
Indole Synthesis

Microwave-assisted organic chemistry is reviewed in the context of the methods employed. A range of technical difficulties indicated that specifically designed reactors were required. Hence, the CSIRO continuous microwave reactor (CMR) and microwave batch reactor (MBR) were developed for organic synthesis. On the laboratory scale, they operated at temperatures (pressures) up to 200°C (1400 kPa) and 260°C (10 MPa), respectively. Advantages and applications of the units are discussed, along with safety issues. Features include the capability for rapid, controlled heating and cooling of reaction mixtures, and elimination of wall effects. Concurrent heating and cooling, and differential heating were unique methodologies introduced to organic synthesis through the MBR. Applications of the microwave reactors for optimizing high-temperature preparations, e.g, the Willgerodt reaction and the Fischer indole synthesis, were demonstrated. Water was a useful pseudo-organic solvent, applicable to environmentally benign synthetic chemistry.

Comparison of Conventional and Microwave Heating for Evaluation of Microwave Effects

2016 ◽  
Vol 69 (8) ◽  
pp. 865 ◽  
Author(s):  
Péter Bana ◽  
István Greiner
Keyword(s):  
Temperature Measurement ◽  
Microwave Heating ◽  
Organic Synthesis ◽  
Convenient Method ◽  
Thermal Effects ◽  
Fibre Optic ◽  
Organic Transformations ◽  
Microwave Assisted ◽  
Microwave Reactor ◽  
Microwave Effects

In microwave-assisted organic synthesis, the question of microwave effects is still debated. Proper examination of these hypothesized phenomena is encumbered by some specific features of microwave heating. We devise a convenient method to eliminate most of the irreproducibility observed in microwave-heated organic transformations by thermal conditioning of the microwave reactor cavity. To show the utility of this approach, we investigated a reaction of 2-chloropyridine, in which microwave conditions were shown to be beneficial by previous studies. Using our method to ensure proper reproducibility together with fibre optic temperature measurement, the observed differences were traced back to large hidden thermal differences, while non-thermal effects could not be detected in the comparison experiments.

Environmentally Benign Procedures for the Preparation and Isolation of 3-Methylcyclopent-2-en-1-one

1997 ◽  
Vol 50 (9) ◽  
pp. 921 ◽  
Author(s):  
Laurence Bagnell ◽  
Marianne Bliese ◽  
Teresa Cablewski ◽  
Christopher R. Strauss ◽  
John Tsanaktsidis
Keyword(s):  
Anion Exchange ◽  
Continuous Flow ◽  
Exchange Resin ◽  
Anion Exchange Resin ◽  
Batch Reactor ◽  
Environmentally Benign ◽  
Isolation Method ◽  
Preferential Adsorption ◽  
Microwave Reactor ◽  
Higher Temperature

A moderately yielding (50±4%) method for obtaining 3-methylcyclopent-2-en-1-one from hexane-2,5-dione in ≥99·5% purity was developed, using 2·1% (w/v) of aqueous KOH at reflux. However, the yield was increased to 80±5% by using considerably lower concentrations of base (<0·1%) and higher temperature (200°C) with a conventionally heated autoclave or a microwave batch reactor. The preparation was scaled up with a larger autoclave and also with a continuous flow microwave reactor. The dione impurity was removed from the enone by preferential adsorption on an anion-exchange resin in the bisulfite form. The product was recovered from the aqueous phase with a hydrophobic resin. This environmentally benign, non-extractive isolation method has potential for broad applicability in cleaner production.

Microwave Assisted Organic Synthesis: Cross Coupling and Multicomponent Reactions

2013 ◽  
Vol 17 (5) ◽  
pp. 474-490 ◽  
Author(s):  
Amit Kumar Gupta ◽  
Neetu Singh ◽  
Krishna Nand Singh
Keyword(s):  
Organic Synthesis ◽  
Multicomponent Reactions ◽  
Cross Coupling ◽  
Microwave Assisted

The molecular diversity of 1,8-diaminonaphthalene in organic chemistry

2020 ◽  
Vol 23 ◽  
Author(s):  
Ghodsi Mohammadi Ziarani ◽  
Fatemeh Mohajer ◽  
Suraj N. Mali
Keyword(s):  
Organic Chemistry ◽  
Organic Synthesis ◽  
Molecular Diversity ◽  
Organic Reactions ◽  
Recent Application ◽  
Organic Structure

: 1,8-diaminonaphthalene (1,8-DAN) with special organic structure was applied in organic synthesis to provide efficient complex scaffolds, through the two or four-component fashion. This review highlights its recent application in organic reactions under different conditions and heterogynous catalysts to produce various molecules, which were used as medicines, sensors, and dyes.

Metal and Non-Metal Catalysts in the Synthesis of Five-Membered S-Heterocycles

2019 ◽  
Vol 16 (2) ◽  
pp. 258-275 ◽  
Author(s):  
Navjeet Kaur
Keyword(s):  
Organic Synthesis ◽  
Biological Activities ◽  
Reaction Times ◽  
Research Field ◽  
Environmentally Benign ◽  
Metal Catalyst ◽  
Efficient Synthesis ◽  
Heterocyclic Molecules ◽  
The Past ◽  
Harsh Conditions

Background:A wide variety of biological activities are exhibited by N, O and S containing heterocycles and recently, many reports appeared for the synthesis of these heterocycles. The synthesis of heterocycles with the help of metal and non-metal catalyst has become a highly rewarding and important method in organic synthesis. This review article concentrated on the synthesis of S-heterocylces in the presence of metal and non-metal catalyst. The synthesis of five-membered S-heterocycles is described here.Objective:There is a need for the development of rapid, efficient and versatile strategy for the synthesis of heterocyclic rings. Metal, non-metal and organocatalysis involving methods have gained prominence because traditional conditions have disadvantages such as long reaction times, harsh conditions and limited substrate scope.Conclusion:The metal-, non-metal-, and organocatalyst assisted organic synthesis is a highly dynamic research field. For ßthe chemoselective and efficient synthesis of heterocyclic molecules, this protocol has emerged as a powerful route. Various methodologies in the past few years have been pointed out to pursue more sustainable, efficient and environmentally benign procedures and products. Among these processes, the development of new protocols (catalysis), which avoided the use of toxic reagents, are the focus of intense research.

Modern Organic Synthesis in the Laboratory

2008 ◽  
Author(s):  
Jie Jack Li ◽  
Chris Limberakis ◽  
Derek A. Pflum
Keyword(s):  
Organic Chemistry ◽  
Graduate Students ◽  
Organic Synthesis ◽  
Functional Group ◽  
Bond Formation ◽  
Reaction Conditions ◽  
Carbon Bond ◽  
Oxidation Reduction ◽  
Carbon Carbon Bond ◽  
Daunting Task

Searching for reaction in organic synthesis has been made much easier in the current age of computer databases. However, the dilemma now is which procedure one selects among the ocean of choices. Especially for novices in the laboratory, it becomes a daunting task to decide what reaction conditions to experiment with first in order to have the best chance of success. This collection intends to serve as an "older and wiser lab-mate" one could have by compiling many of the most commonly used experimental procedures in organic synthesis. With chapters that cover such topics as functional group manipulations, oxidation, reduction, and carbon-carbon bond formation, Modern Organic Synthesis in the Laboratory will be useful for both graduate students and professors in organic chemistry and medicinal chemists in the pharmaceutical and agrochemical industries.

scholarly journals Cycloaddition of Thiourea- and Guanidine-Substituted Furans to Dienophiles: A Comparison of the Environmentally-Friendly Methods

2020 ◽  
Vol 3 (1) ◽  
pp. 57
Author(s):  
Luka Barešić ◽  
Davor Margetić ◽  
Zoran Glasovac
Keyword(s):  
High Pressure ◽  
Functional Groups ◽  
Organic Synthesis ◽  
High Speed ◽  
Environmentally Friendly ◽  
Microwave Assisted ◽  
Pressure Synthesis ◽  
Ultrasound Assisted ◽  
Substituted Furans ◽  
Guanidine Moiety

The cycloaddition strategy was employed in order to obtain a 7-oxanorbornene framework substituted with a guanidine moiety or its precursor functional groups: protected amine or thiourea. In order to optimize the conditions for the cycloaddition, several environmentally-friendly methods—microwave assisted organic synthesis, high pressure synthesis, high speed vibrational milling, and ultrasound assisted synthesis—were employed. The outcomes of the cycloaddition reactions were interpreted in terms of endo/exo selectivity, the conversion of the reactants to the product, and the isolated yields. In general, our results indicated the HP and HSVM approaches as the methods of choice to give good yields and conversions.

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