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Special Issue "Microwave-Assisted Organic Synthesis"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Organic Synthesis".

Deadline for manuscript submissions: closed (15 October 2015)

Special Issue Editors

Guest Editor
Prof. Dr. Marilena Radoiu

Independent Consultant, EMLYON Business School, Lyon Area, France
Website | E-Mail
Interests: microwave processing in solid; liquid and gas phase with applications to cosmetics, pharmaceuticals, nutraceuticals, food, ceramics, etc.; scale up and commercialization of microwave processes to maximize the process benefits which include improved energy efficiency; product quality and throughput with reduced environmental impact including carbon footprint; fundamental understanding of the microwave/material interactions at a molecular level
Guest Editor
Dr. Jean Jacques Vanden Eynde

Formerly head of the Department of Organic Chemistry (FS), University of Mons-UMONS, 7000 Mons, Belgium
Website | E-Mail
Interests: heterocycles; microwave-induced synthesis; medicinal chemistry; green chemistry
Guest Editor
Dr. Annie Mayence

Formerly professor at the Haute Ecole Provinciale de Hainaut-Condorcet, 7330 Saint-Ghislain, Belgium
Website | E-Mail
Interests: medicinal chemistry, organic synthesis, parasitic diseases, orphan drugs

Special Issue Information

Dear Colleagues,

The last century has clearly demonstrated the impact of technology on society. As the industrial processing continues the drive towards higher performance and lower costs, demanding new synthesis processes become a necessity. Balanced with the performance and quality requirements for current and future processing materials are the Environmental, Safety and Health concerns surrounding these processes. The shape and direction of further technological development also has to consider that many of these process steps are critically dependent on energy transfer into the reaction to deliver the highest levels of process performance and end-product reliability.

Microwave (MW) heating is a technique of heating dielectric materials, i.e., materials that have no or low electrical conductivity; in most cases these materials are also poorly conductive thermally. Conventional heating techniques, based on heat transfer phenomena, are inefficient for heating dielectrics. MW techniques dissipate heat within the material by an electromagnetic phenomenon of energy transfer. When discussing the performance of the microwave technique in comparison with other dielectric heating techniques (i.e., radio frequency), there are two main advantages that should be highlighted: high energy transfer due to higher frequency (915 MHz or 2450 MHz vs. 13.56 MHz or 27.12 MHz) and reduced breakdown risk due to the lower electric field strength.

It is well known that energy is often one of the most significant uncontrolled variables in an experiment. Microwaves have the potential to change that, partly by the fundamental way the energy is delivered to the molecules of interest, and partly by the electronic controls in the apparatus, facilitating the setting and recording of time, energy level, final temperature and so forth.

The present Special Issue of Molecules entitled “Microwave-Assisted Organic Synthesis” aims to attract all scientists working in the synthesis and characterization of microwave-assisted synthesis without restrictions to the value of the microwave frequency, the phase of the system, and the scale of the performed process. All papers submitted are welcome as we hope this effort to bring the SMM community together will receive the appreciation and support it deserves.

Dr. Marilena Radoiu
Dr. Jean Jacques Vanden Eynde
Dr. Annie Mayence
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.


Keywords

  • microwaves assisted chemistry
  • plasma
  • frequency
  • catalysis

Published Papers (5 papers)

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Research

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Open AccessCommunication Microwave-Assisted Superheating and/or Microwave-Specific Superboiling (Nucleation-Limited Boiling) of Liquids Occurs under Certain Conditions but is Mitigated by Stirring
Molecules 2015, 20(12), 21672-21680; doi:10.3390/molecules201219793
Received: 28 October 2015 / Revised: 17 November 2015 / Accepted: 20 November 2015 / Published: 4 December 2015
Cited by 4 | PDF Full-text (2519 KB) | HTML Full-text | XML Full-text
Abstract
Temporary superheating and sustained nucleation-limited “superboiling” of unstirred liquids above the normal atmospheric boiling point have been documented during microwave heating. These phenomena are reliably observed under prescribed conditions, although the duration (of superheating) and magnitude (of superheating and superboiling) vary according to
[...] Read more.
Temporary superheating and sustained nucleation-limited “superboiling” of unstirred liquids above the normal atmospheric boiling point have been documented during microwave heating. These phenomena are reliably observed under prescribed conditions, although the duration (of superheating) and magnitude (of superheating and superboiling) vary according to system parameters such as volume of the liquid and the size and shape of the vessel. Both phenomena are mitigated by rapid stirring with an appropriate stir bar and/or with the addition of boiling chips, which provide nucleation sites to support the phase-change from liquid to gas. With proper experimental design and especially proper stirring, the measured temperature of typical organic reaction mixtures heated at reflux will be close to the normal boiling point temperature of the solvent, whether heated using microwave radiation or conventional convective heat transfer. These observations are important to take into consideration when comparing reaction rates under conventional and microwave heating. Full article
(This article belongs to the Special Issue Microwave-Assisted Organic Synthesis)
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Open AccessArticle Molecular Differentiated Initiator Reactivity in the Synthesis of Poly(caprolactone)-Based Hydrophobic Homopolymer and Amphiphilic Core Corona Star Polymers
Molecules 2015, 20(11), 20131-20145; doi:10.3390/molecules201119681
Received: 7 October 2015 / Revised: 26 October 2015 / Accepted: 27 October 2015 / Published: 9 November 2015
Cited by 1 | PDF Full-text (3156 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Macromolecules that possess three-dimensional, branched molecular structures are of great interest because they exhibit significantly differentiated application performance compared to conventional linear (straight chain) polymers. This paper reports the synthesis of 3- and 4-arm star branched polymers via ring opening polymerisation (ROP) utilising
[...] Read more.
Macromolecules that possess three-dimensional, branched molecular structures are of great interest because they exhibit significantly differentiated application performance compared to conventional linear (straight chain) polymers. This paper reports the synthesis of 3- and 4-arm star branched polymers via ring opening polymerisation (ROP) utilising multi-functional hydroxyl initiators and Sn(Oct)2 as precatalyst. The structures produced include mono-functional hydrophobic and multi-functional amphiphilic core corona stars. The characteristics of the synthetic process were shown to be principally dependent upon the physical/dielectric properties of the initiators used. ROP’s using initiators that were more available to become directly involved with the Sn(Oct)2 in the “in-situ” formation of the true catalytic species were observed to require shorter reaction times. Use of microwave heating (MWH) in homopolymer star synthesis reduced reaction times compared to conventional heating (CH) equivalents, this was attributed to an increased rate of “in-situ” catalyst formation. However, in amphiphilic core corona star formation, the MWH polymerisations exhibited slower propagation rates than CH equivalents. This was attributed to macro-structuring within the reaction medium, which reduced the potential for reaction. It was concluded that CH experiments were less affected by this macro-structuring because it was disrupted by the thermal currents/gradients caused by the conductive/convective heating mechanisms. These gradients are much reduced/absent with MWH because it selectively heats specific species simultaneously throughout the entire volume of the reaction medium. These partitioning problems were overcome by introducing additional quantities of the species that had been determined to selectively heat. Full article
(This article belongs to the Special Issue Microwave-Assisted Organic Synthesis)
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Open AccessArticle Synthetic Development of New 3-(4-Arylmethylamino)butyl-5-arylidene-rhodanines under Microwave Irradiation and Their Effects on Tumor Cell Lines and against Protein Kinases
Molecules 2015, 20(7), 12412-12435; doi:10.3390/molecules200712412
Received: 27 May 2015 / Revised: 17 June 2015 / Accepted: 30 June 2015 / Published: 8 July 2015
Cited by 4 | PDF Full-text (847 KB) | HTML Full-text | XML Full-text
Abstract
A new route to 3-(4-arylmethylamino)butyl-5-arylidene-2-thioxo-1,3-thiazolidine-4-one 9 was developed in six steps from commercial 1,4-diaminobutane 1 as starting material. The key step of this multi-step synthesis involved a solution phase “one-pot two-steps” approach assisted by microwave dielectric from N-(arylmethyl)butane-1,4-diamine hydrochloride 6af
[...] Read more.
A new route to 3-(4-arylmethylamino)butyl-5-arylidene-2-thioxo-1,3-thiazolidine-4-one 9 was developed in six steps from commercial 1,4-diaminobutane 1 as starting material. The key step of this multi-step synthesis involved a solution phase “one-pot two-steps” approach assisted by microwave dielectric from N-(arylmethyl)butane-1,4-diamine hydrochloride 6af (as source of the first point diversity) and commercial bis-(carboxymethyl)-trithiocarbonate reagent 7 for construction of the rhodanine platform. This platform was immediately functionalized by Knoevenagel condensation under microwave irradiation with a series of aromatic aldehydes 3 as second point of diversity. These new compounds were prepared in moderate to good yields and the fourteen synthetic products 9an have been obtained with a Z-geometry about their exocyclic double bond. These new 5-arylidene rhodanines derivatives 9an were tested for their kinase inhibitory potencies against four protein kinases: Human cyclin-dependent kinase 5-p25, HsCDK5-p25; porcine Glycogen Synthase Kinase-3, GSK-3α/β; porcine Casein Kinase 1, SsCK1 and human HsHaspin. They have also been evaluated for their in vitro inhibition of cell proliferation (HuH7 D12, Caco 2, MDA-MB 231, HCT 116, PC3, NCI-H727, HaCat and fibroblasts). Among of all these compounds, 9j presented selective micromolar inhibition activity on SsCK1 and 9i exhibited antitumor activities in the HuH7 D12, MDA-MBD231 cell lines. Full article
(This article belongs to the Special Issue Microwave-Assisted Organic Synthesis)
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Open AccessArticle Microwave-Assisted Condensation Reactions of Acetophenone Derivatives and Activated Methylene Compounds with Aldehydes Catalyzed by Boric Acid under Solvent-Free Conditions
Molecules 2015, 20(6), 11617-11631; doi:10.3390/molecules200611617
Received: 28 May 2015 / Revised: 14 June 2015 / Accepted: 15 June 2015 / Published: 23 June 2015
Cited by 3 | PDF Full-text (794 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
We here disclosed a new protocol for the condensation of acetophenone derivatives and active methylene compounds with aldehydes in the presence of boric acid under microwave conditions. Implementation of the reaction is simple, healthy and environmentally friendly owing to the use of a
[...] Read more.
We here disclosed a new protocol for the condensation of acetophenone derivatives and active methylene compounds with aldehydes in the presence of boric acid under microwave conditions. Implementation of the reaction is simple, healthy and environmentally friendly owing to the use of a non-toxic catalyst coupled to a solvent-free procedure. A large variety of known or novel compounds have thus been prepared, including with substrates bearing acid or base-sensitive functional groups. Full article
(This article belongs to the Special Issue Microwave-Assisted Organic Synthesis)

Review

Jump to: Research

Open AccessReview Heterogeneous Phase Microwave-Assisted Reactions under CO2 or CO Pressure
Molecules 2016, 21(3), 253; doi:10.3390/molecules21030253
Received: 31 December 2015 / Revised: 6 February 2016 / Accepted: 17 February 2016 / Published: 24 February 2016
Cited by 1 | PDF Full-text (2391 KB) | HTML Full-text | XML Full-text
Abstract
The present review deals with the recent achievements and impressive potential applications of microwave (MW) heating to promote heterogeneous reactions under gas pressure. The high versatility of the latest generation of professional reactors combines extreme reaction conditions with safer and more efficient protocols.
[...] Read more.
The present review deals with the recent achievements and impressive potential applications of microwave (MW) heating to promote heterogeneous reactions under gas pressure. The high versatility of the latest generation of professional reactors combines extreme reaction conditions with safer and more efficient protocols. The double aims of this survey are to provide a panoramic snapshot of MW-assisted organic reactions with gaseous reagents, in particular CO and CO2, and outline future applications. Stubborn and time-consuming carbonylation-like heterogeneous reactions, which have not yet been studied under dielectric heating, may well find an outstanding ally in the present protocol. Full article
(This article belongs to the Special Issue Microwave-Assisted Organic Synthesis)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Type of Paper: Review
Title: Applications of Microwave-Assisted Synthesis to Lanthanide Chemistry
Authors: Lauren E. Hopper and Matthew J. Allen
Affiliations: Wayne State University, Department of Chemistry
Abstract: This review describes microwave-assisted reactions with application to lanthanide chemistry from the
past 20 years. It focuses on the solution-phase chemistry relevant to ligand design and applications involving
lanthanide complexes.
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