Microwave-induced organic reaction enhancement (more) chemistry: Techniques for rapid, safe and inexpensive synthesis

ArticleinResearch on Chemical Intermediates 20(1):1-11 · June 2010with44 Reads
Impact Factor: 1.22 · DOI: 10.1163/156856794X00027
Abstract

Synthetic organic reactions have been conducted under microwave irradiation in open vessels in unaltered domestic microwave ovens. Reaction times vary from a few seconds for sub-milligram reactions to about 15 minutes for reactions carried out on a scale of hundreds of grams. Promising results have been obtained for several condensations, as well as the Bischler-Napieralski reaction, the Wolff-Kishner reduction, free radical dehalogenation reactions, and other standard synthetic operations. Rapid catalytic transfer hydrogenation using ammonium formate as the source of hydrogen has been conducted at about 100-130 °C under microwave irradiation. Meaningful, safe and inexpensive synthetic experiments for undergraduate and pre-college students have been developed and tested. The MORE chemistry techniques make it possible to use simple apparatus and very short reaction times. Commercial microwave ovens are now essential equipment in our research and teaching laboratories [1-3]. These ovens are relatively inexpensive, easy to move from one laboratory and set up in another, and safe to operate. Glass, plastics, and ceramics are essentially transparent to microwaves whereas many organic compounds are dipolar in nature and absorb microwave energy readily. We have found that untraditional experimental arrangements are possible for conducting a wide variety of organic reactions in open vessels inside domestic microwave ovens. Depending on the quantity of reactants, most reactions (on a scale of milligrams to several grams) can be completed in minutes instead of hours. One important element of our “Microwave-induced Organic Reaction Enhancement” (MORE) chemistry is the proper choice of a microwave energy transfer agent as the reaction medium.

    • "Many of the enzymatic reactions of DNA/RNA are time consuming as they require minutes to hours for completion. Alternatively, as microwave radiations have shown promising results in enhancing the rate of catalysis in food and fermentation [5] , protein engineering [6] and chemical syntheses [7, 8] , their implementation in enzymatic reactions of nucleic acids can provide rapid time saving alternate to conventional lengthy protocols. Earlier, we have shown that the use of microwave radiations for the enzymatic reactions in molecular biology can enhance the rate of reactions, such as DNA digestion, ligation, phosphorylation, and dephosphorylation [9] . "
    [Show abstract] [Hide abstract] ABSTRACT: Herein we report microwave-induced enhancement of the reactions catalyzed by Escherichia coli DNA polymerase I and avian myeloblastosis virus-reverse transcriptase. The reactions induced by microwaves result in a highly selective synthesis of nucleic acids in 10-50 seconds. In contrast, same reactions failed to give desired reaction products when carried out in the same time periods, but without microwave irradiation. Each of the reactions was carried out for different duration of microwave exposure time to find the optimum reaction time. The products produced by the respective enzyme upon microwave irradiation of the reaction mixtures were identical to that produced by the conventional procedures. As the microwave-assisted reactions are rapid, microwave could be a useful alternative to the conventional and time consuming procedures of enzymatic synthesis of nucleic acids.
    Full-text · Article · May 2016 · Nucleosides Nucleotides & Nucleic Acids
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    • "Similarly, Kumar and Joshi reported the reaction of several substituted β-diketones/β-ketoesters of pyrazolo[4,3-d]pyrimidin-7-one with 34 under microwave power at 300W without solvent using silica to yield several pyrazolo[4,3-d]pyrimidin-7-one based 3H-1,5-benzodiaze- pines [72]. Jiang et al. reported an efficient tandem methodology for the synthesis of highly functionalized pentacyclic isoindolefused benzo[b,e][1] [4]diazepine derivatives (57) in aqueous "
    [Show abstract] [Hide abstract] ABSTRACT: The use of microwave energy in chemical reactions has revolutionized the field of heterocyclic chemistry in the past two decades. Synergy of microwave methodology with reactions performed on support media and/or in the absence of solvent constitutes an environmentally clean technique, that offers tremendous advantages such as clean chemistry, reduction in reaction times, improved yields, and applicability to wide range of reactions, safety and tremendous scope for automation over the traditional heating. The benzoannulated azaheterocycles display an impressive repertoire of biological activities. The present review will provide an in-depth view of microwave-assisted synthetic methodologies of benzo-fused seven-membered azaheterocycles such as benzodiazepines, benzothiazepines and benzoxazepines.
    Full-text · Article · Sep 2014 · Mini-Reviews in Organic Chemistry
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    • "The feasibility of microwave assisted synthesis has been demonstrated in various transformations whose main features are enhanced reaction rates, greater selectivity and experimental ease of manipulation leading to efficient, environmentally friendly in addition to cost effective synthetic pathways to several compounds [22,23]. Moreover, the use of microwave irradiation in this regard is now a well-established procedure in MORE (microwave induced organic reaction enhancement) chemistry [24]. In the present study, a direct microwave-assisted one-step synthesis of some fenamic acid hydrazides from their corresponding acids was developed. "
    [Show abstract] [Hide abstract] ABSTRACT: A facile and efficient method for synthesis of fenamic acid hydrazides from their acids in one-step reaction under microwave irradiation and solvent-free conditions was developed. Compared with the two-step conventional heating method, the process was simple, the reaction time was very short and the yields were almost quantitative.
    Full-text · Article · Dec 2011 · Molecules
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