Progress in Microwave-Aided Chemical Synthesis

2012 ◽  
Vol 65 (12) ◽  
pp. 1647 ◽  
Author(s):  
Hani Mutlak A. Hassan ◽  
Steve Harakeh ◽  
Kaltoom A. Sakkaf ◽  
Iuliana Denetiu

The continuing use of microwave (µwave) energy in chemical synthesis has been impressive over the past decade, with many reports incorporating µwave-based reactions. Two of the major benefits of using µwave heating are the remarkable decrease in reaction times and often high yield of products in comparison with classical heating, an ideal technology for synthetic chemists. Herein, we highlight some exciting examples of its recent utility in organic, medicinal, and natural product synthetic endeavours.

2007 ◽  
Vol 79 (12) ◽  
pp. 2189-2216 ◽  
Author(s):  
Rebecca M. Wilson ◽  
Samuel J. Danishefsky

This account traces the development of our synthetic glycopeptide- and glycoprotein-based research program over the past decade. We recount the syntheses of a number of biologically relevant, natural product-inspired glycopeptide constructs, including those associated with prostate specific antigen (PSA) and with the gp120 surface envelope protein of HIV. We also describe our progress toward the synthesis of the multiply glycosylated protein, erythropoietin (EPO). Particular emphasis is placed on the development of enabling methodologies which allow for the ligation of complex glycopeptide fragments, thus rendering it possible to access, through purely synthetic means, homogeneous, multidomainal glycopeptide and glycoprotein constructs.


2020 ◽  
Vol 17 (11) ◽  
pp. 832-836
Author(s):  
Manijeh Nematpour ◽  
Hossein Fasihi Dastjerdi ◽  
Mehdi Jahani ◽  
Sayyed Abbas Tabatabai

A simple and appropriate procedure for the synthesis of quinazoline-2,4(1H,3H)-dione derivatives from isocyanides, aniline and isocyanate via the Cu-catalyzed intramolecular C-H activation reaction is reported. The advantages of this method are one-pot conditions, accessible starting materials- catalyst, high yield of products, and short reaction times. The structures are confirmed spectroscopically (1H- and 13C-NMR, IR and EI-MS) and by elemental analyses.


2019 ◽  
Vol 16 (2) ◽  
pp. 258-275 ◽  
Author(s):  
Navjeet Kaur

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.


Synlett ◽  
2019 ◽  
Vol 30 (11) ◽  
pp. 1289-1302 ◽  
Author(s):  
Phil Servatius ◽  
Lukas Junk ◽  
Uli Kazmaier

Peptide modifications via C–C bond formation have emerged as valuable tools for the preparation and alteration of non-proteinogenic amino acids and the corresponding peptides. Modification of glycine subunits in peptides allows for the incorporation of unusual side chains, often in a highly stereoselective manner, orchestrated by the chiral peptide backbone. Moreover, modifications of peptides are not limited to the peptidic backbone. Many side-chain modifications, not only by variation of existing functional groups, but also by C–H functionalization, have been developed over the past decade. This account highlights the synthetic contributions made by our group and others to the field of peptide modifications and their application in natural product syntheses.1 Introduction2 Peptide Backbone Modifications via Peptide Enolates2.1 Chelate Enolate Claisen Rearrangements2.2 Allylic Alkylations2.3 Miscellaneous Modifications3 Side-Chain Modifications3.1 C–H Activation3.1.1 Functionalization via Csp3–H Bond Activation3.2.2 Functionalization via Csp2–H Bond Activation3.2 On Peptide Tryptophan Syntheses4 Conclusion


2020 ◽  
Vol 9 (1) ◽  
pp. 919-923

Biginelli, an important multicomponent reaction provides an avenue for the synthesis of different biologically active heterocyclic compounds. During the past decade, one pot multicomponent reactions have attracted the attention of organic and medicinal chemists due to high atom economy, time and enery saving convergent nature. The present manuscript reports a simple one pot three component synthesis of 3, 4-dihydroprimidin-2(1H)-thiones from various diversely substituted aldehydes, ethyl acetoacetate and thiourea using a orange peel powder as a natural catalyst on ultrasonic irradiation in aqueous medium as the solvent. The advantages of this reaction are less reaction time, high yield, easy availability of the catalyst and green nature.


Author(s):  
Ming Toh ◽  
Kameshwari Chengan ◽  
Tanith Hanson ◽  
Paul S. Freemont ◽  
Simon J. Moore

2021 ◽  
Vol 08 ◽  
Author(s):  
Adarsh Sahu

Background: 1,2,3-triazole is considered widely explored scaffolds by medicinal chemists because of their therapeutic importance. The structural characteristics of 1,2,3-triazoles allow this to mimic certain functional groups demonstrating its utility to prepare new medicinal compounds using the concept of bioisosterism and molecular hybridization. Centered on Huisgens cycloaddition reaction, over the past decade and a half, click chemistry approaches were developed to furnish triazole derivatives with various applications ranging from drugs to bioconjugation linkers. Objective: In the present review, we aim to highlight the different approaches developed for the synthesis of 1,2,3-triazole derivatives and in particular advances in synthetic methods for the last 16 years. This review is also intended to help researchers for finding potential future directions and scope in the development of synthetic strategies. Conclucion: As summarized through the compilation of recent advances for 1,2,3-triazole synthesis, it is clear that these protocols have numerous advantages such as cleaner reaction profile, shorter reaction times, excellent product yields, environmentally benign milder reactions, and safe operations.


2004 ◽  
Vol 120 ◽  
pp. 555-562
Author(s):  
D. Apelian ◽  
S. K. Chaudhury

Heat Treatment and post casting treatments of cast components has always been an important step in the control of microstructure, and resultant properties. In the past, the solutionizing, quenching and ageing process steps may have “required” in total over 20 hours of processing time. With the advent of fluidized bed reactors (FB), processing time has been dramatically reduced. For example, instead of 8-10 hours solutionizing time in a conventional furnace, the time required in FB is less than an hour. Experiments with Al-Si-Mg alloy, (both modified with Sr, and unmodified) were performed, having different diffusion distances (different DAS), and for different reaction times and temperatures. Both the model and the experimental results are presented and discussed.


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