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

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.

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.


2021 ◽  
Vol 17 ◽  
pp. 2848-2893
Author(s):  
Austin Pounder ◽  
William Tam

The development of environmentally benign, inexpensive, and earth-abundant metal catalysts is desirable from both an ecological and economic standpoint. Certainly, in the past couple decades, iron has become a key player in the development of sustainable coupling chemistry and has become an indispensable tool in organic synthesis. Over the last ten years, organic chemistry has witnessed substantial improvements in efficient synthesis because of domino reactions. These protocols are more atom-economic, produce less waste, and demand less time compared to a classical stepwise reaction. Although iron-catalyzed domino reactions require a mindset that differs from the more routine noble-metal, homogenous iron catalysis they bear the chance to enable coupling reactions that rival that of noble-metal-catalysis. This review provides an overview of iron-catalyzed domino coupling reactions of π-systems. The classifications and reactivity paradigms examined should assist readers and provide guidance for the design of novel domino reactions.


2018 ◽  
Vol 15 (3) ◽  
pp. 341-369 ◽  
Author(s):  
Ankita Chaudhary ◽  
Jitender M. Khurana

Background: Xanthene is pharmacologically important oxygen containing heterocyclic moeity exhibiting an array of potent biological activities like antibacterial, antiviral, antiinflammatory, antitumor, antioxidant, antiplasmodial etc. Other useful applications of these heterocycles are as fluorescent materials for the visualization of biomolecules and in laser technology. Objective: This review gives an insight of the literature available on the methods for the construction of xanthene nucleus. This review article can be reasonably encouraging for those involved in the synthesis of molecules exhibiting a wide range of biological activities involving xanthene as central nucleus and would provide them assistance in developing new eco-friendly, efficient and economical viable methods. Conclusion: Owing to diverse applications of xanthenes, various synthetic methodologies have been developed, whether to construct this privileged scaffold. Many of the reported methods involve the use of various harsh catalysts/reagents that are not environmentally benign, produce a large amount of waste and need longer reaction times. The sustainable and diversity oriented synthesis of xanthene scaffold which incorporates Green Chemistry tools like multicomponent reaction approach, heterogeneous catalysts, alternate reaction media such as water, ionic liquids, polyethylene glycol etc. has also been developed.


2009 ◽  
Vol 87 (9) ◽  
pp. 1209-1212 ◽  
Author(s):  
Hongshe Wang ◽  
June Zeng

Chalcones are useful intermediates in organic synthesis and exhibit a large number of different biological activities. Chalcones have been synthesized in high yields by Claisen–Schmidt condensation of substituted acetophenones with various aromatic aldehydes in the presence of 10 mol% of iodine at room temperature by grinding under solvent-free conditions.


2014 ◽  
Vol 68 (8) ◽  
Author(s):  
Hamzeh Kiyani ◽  
Fatemeh Ghorbani

Abstract2-Amino-4-aryl-4H-benzo[h]chromenes and 3-amino-1-aryl-1H-benzo[f]chromenes were prepared by treating cyano-methylene compounds (malononitrile or ethyl cyanoacetate), substituted aromatic aldehydes, and naphtholic compounds in the presence of potassium phthalimide as a green, mild, efficient, and commercially available organocatalyst in aqueous media. The procedure was readily conducted and affords remarkable advantages such as safety, short reaction times, environmentally benign milder reaction conditions, no organic solvent required, and high yields.


2019 ◽  
Vol 16 (8) ◽  
pp. 637-642 ◽  
Author(s):  
Kotthireddy Kavitha ◽  
Devulapally Srikrishna ◽  
Pramod Kumar Dubey ◽  
Pasula Aparna

An efficient and convenient method for the condensation of various aldehydes with 2-(4-(2- oxo-2H-chromen-3-yl)thiazol-2-yl)acetonitrile has been demonstrated via triphenylphosphinecatalyzed Knoevenagel condensation in good to excellent yields. The effect of solvent on this reaction was studied. In addition, a tandem method for the synthesis of 2-(4-(2-oxo-2H-chromen-3-yl)thiazol-2- yl)acetonitrile has been outlined using tetrabutylammonium tribromide as an efficient, green and ecofriendly reagent. Subsequently, the latter was reacted with various aromatic aldehydes in the presence of PEG-600 as reaction media to afford the title compounds. These reactions have widened the scope and applicability of the use of tetrabutylammonium tribromide, triphenylphosphine in organic synthesis. All these synthesized compounds were characterized by IR, 1H-NMR, Mass and 13C-NMR spectral data.


2020 ◽  
Vol 07 ◽  
Author(s):  
Rajib Sarkar ◽  
Chhanda Mukhopadhyay

Abstract:: The use of small organic molecules as organocatalysts in organic synthesis has intensely studied over the past decade. In this emerging field, considerable study has led to the introduction of various efficient organocatalyzed synthetic methods of carbon-carbon and carbon-hetero atom bond formations. The use of these organocatalysts also emerged environmentally benign reaction conditions compared to the metal catalyzed transformations. In this review, we make a special attention on the most recent organocatalytic protocols reported for the synthesis of heterocycles. The works have been outlined by depending on the organocatalysts used as (i) nitrogen based molecules as organocatalyst, (ii) NHCs as organocatalyst, and (iii) phosphorus based molecules as organocatalyst. The discussion intends to reveal the scope as well as vitality of organocatalysis in the area of heterocycle synthesis.


2015 ◽  
Vol 5 (5) ◽  
pp. 2554-2574 ◽  
Author(s):  
Xiao-Yun Dong ◽  
Zi-Wei Gao ◽  
Ke-Fang Yang ◽  
Wei-Qiang Zhang ◽  
Li-Wen Xu

Silver nanoparticles catalysis has been of great interest in organic synthesis and has expanded rapidly in the past ten years because of nanosilver catalysts' unique reactivity and selectivity, stability, as well as recyclability in catalytic reactions.


Synthesis ◽  
2021 ◽  
Author(s):  
Angelica Peñaranda ◽  
Carlos Eduardo E. Puerto Galvis ◽  
Mario Alberto Macias ◽  
Cristian Ochoa-Puentes ◽  
Vladimir V. Kouznetsov

A tandem approach was developed for the efficient synthesis of substituted chromeno[4,3-b]quinolines from arylamines and O-cinnamyloxy salicylaldehydes under metal-catalyst and photosensitizer-free reaction conditions. Our protocol is based on an inexpensive I2/DMSO system in which molecular iodine first acts as a Lewis acid to promote the formation of the corresponding imine bearing the alkene moiety, then, this species fulfills a second role by catalyzing the intramolecular aza-Diels-Alder cycloaddition to generate the respective tetrahydro-chromenoquinolines as an intermediates. Finally, the dual behaviour of DMSO as an oxidant and as a solvent resulted crucial at this stage, allowing the regeneration of I2 and promoting the aromatization of the tetrahydro-chromenoquinoline intermediates to yield the desired 7-aryl-6H-chromeno[4,3-b]quinolines. This protocol features by being mild, easy to perform, high step-economy (tandem process) and for providing a new access to biologically important nitrogen and oxygen containing heterocyclic molecules.


2020 ◽  
Author(s):  
Aidan Kelly ◽  
Peng-Jui (Ruby) Chen ◽  
Jenna Klubnick ◽  
Daniel J. Blair ◽  
Martin D. Burke

<div> <div> <div> <p>Existing methods for making MIDA boronates require harsh conditions and complex procedures to achieve dehydration. Here we disclose that a pre-dried form of MIDA, MIDA anhydride, acts as both a source of the MIDA ligand and an in situ desiccant to enable a mild and simple MIDA boronate synthesis procedure. This method expands the range of sensitive boronic acids that can be converted into their MIDA boronate counterparts. Further utilizing unique properties of MIDA boronates, we have developed a MIDA Boronate Maker Kit which enables the direct preparation and purification of MIDA boronates from boronic acids using only heating and centrifuge equipment that is widely available in labs that do not specialize in organic synthesis. </p> </div> </div> </div>


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