Recent Achievement in the Synthesis of Thiophenes

: Thiophene derivatives are aromatic five-membered ring compounds made up of one Sulphur as heteroatom. These compounds are present in a large number of natural and unnatural compounds with valuable bioactivities. Many of them have a wide range of applications in medicinal chemistry such as antimicrobial, anticancer, antiparasitic, anti-inflammatory, and antihypertensive activities. Some of them are famous drugs in the market nowadays such as Cefoxitin, Cephalothin, Cephaloridine, Temocillin, tinoridine, tiaprofenic acid, tenoxicam, suproprofen and Raltitrexed. The use of thiophenes derivatives also has been found in other fields. The application of thiophenes in organic materials thank to their electronic properties has been reported. In organic synthesis, thiophenes also have drawn attention of chemists because of their values as intermediates. The employment of thiophene derivatives in agrochemicals, flavors, and dyes has also been found. Due to diverse applications, the synthesis of thiophene derivatives has attracted a lot of attention. Numerous known synthetic methods such as Gewald and Fiesselmann methods have been modified and improved. Furthermore, a large number of novel synthetic approaches to the synthesis of thiophenes have been developed. This review will focus on considerable studies on the synthesis of thiophenes which date back from 2012. In this review, we discussed recent achievement in the synthesis of thiophene derivatives. Some established methods have been modified and improved, while other novel methods have been discovered. Diverse catalysts were employed for these transformations. In some syntheses, reaction mechanisms were also displayed. Many methods for the synthesis of thiophenes have been developed recently. In the near future, more imaginative approaches for the synthesis of thiophenes will be investigated to improve the efficiency and versatility or to use environmentally friendly and economical procedures. Application to natural product synthesis and drug synthesis is probably the next challenge in the field.

A Review on Onychine and its Analogs: Synthesis and Biological Activity

10.2174/1570179417666191218112842 ◽

2020 ◽

Vol 17 (1) ◽

pp. 3-22

Author(s):

Claudia R.B. Gomes ◽

Marcus V.N. de Souza ◽

Victor Facchinetti

Keyword(s):

Biological Activity ◽

Multicomponent Reactions ◽

Diels Alder ◽

Synthetic Methods ◽

Reaction Conditions ◽

Low Concentrations ◽

Wide Range ◽

Intramolecular Cyclizations ◽

Synthetic Approaches ◽

Operational Simplicity

Background: Onychine is a 4-azafluorenone alkaloid isolated from the Annonaceae family, in low concentrations. Onychine and its analogs exhibit a wide range of pharmacological activities such as antifungal, antibacterial, anticancer, and antimalarial. Because of the high bioactivity of some 4-azafluorenone derivatives, several synthetic methods have been developed for their procurement. Objective: Considering the importance of these alkaloids, we aim to present the main synthetic approaches to onychines and its derivatives and the biological activity of some 4-azafluorenones. Methods: The most prominent methodologies for the synthesis of onychines were reviewed. Results: In this work, we cover many synthetic approaches for the synthesis of onychine and 4-azafluorenone derivatives including intramolecular cyclizations, multicomponent reactions, microwave-assisted multicomponent reactions, Diels-alder reactions, among others. Moreover, we also review the biological activity of 4-azafluorenones. Conclusion: 4-azafluorenones have risen as prominent structures in medicinal chemistry; however, most of the time, access to new derivatives involves toxic catalysts, harsh reaction conditions, and long-step procedures. Therefore, the development of new synthetic routes with more operational simplicity, simple purification procedure, good yields, and low environmental impact, is desirable.

Recent Progress in the Synthesis of Quinolines

10.2174/1570179416666190719112423 ◽

2019 ◽

Vol 16 (5) ◽

pp. 671-708 ◽

Cited By ~ 5

Author(s):

Duc Dau Xuan

Keyword(s):

Reaction Mechanisms ◽

Heterocyclic Compounds ◽

Recent Progress ◽

Natural Product Synthesis ◽

Important Class ◽

The Past ◽

New Methods ◽

Substituted Quinolines ◽

Wide Range ◽

Background: Quinoline-containing compounds present in both natural and synthetic products are an important class of heterocyclic compounds. Many of the substituted quinolines have been used in various areas including medicine as drugs. Compounds with quinoline skeleton possess a wide range of bioactivities such as antimalarial, anti-bacterial, anthelmintic, anticonvulsant, antiviral, anti-inflammatory, and analgesic activity. Due to such a wide range of applicability, the synthesis of quinoline derivatives has attracted a lot of attention of chemists to develop effective methods. Many known methods have been expanded and improved. Furthermore, various new methods for quinoline synthesis have been established. This review will focus on considerable studies on the synthesis of quinolines date which back to 2014. Objective: In this review, we discussed recent achievements on the synthesis of quinoline compounds. Some classical methods have been modified and improved, while other new methods have been developed. A vast variety of catalysts were used for these transformations. In some studies, quinoline synthesis reaction mechanisms were also displayed. Conclusion: Many methods for the synthesis of substituted quinoline rings have been developed recently. Over the past five years, the majority of those reported have been based on cycloisomerization and cyclization processes. Undoubtedly, more imaginative approaches to quinoline synthesis will appear in the literature in the near future. The application of known methods to natural product synthesis is probably the next challenge in the field.

Carbocyclic Three- and Four-Membered Ring Compounds

10.1055/b-003-109677 ◽

1997 ◽

Keyword(s):

Membered Ring ◽

Ring Compounds

Double Ring-Closing Approach for the Synthesis of 2,3,6,7-Substituted Anthracene Derivatives

10.26434/chemrxiv.12052647.v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

Birgit Meindl ◽

Katharina Pfennigbauer ◽

Berthold Stöger ◽

Martin Heeney ◽

Florian Glöcklhofer

Keyword(s):

Wittig Reaction ◽

Condensation Reaction ◽

Synthetic Methods ◽

Anthracene Derivative ◽

Double Ring ◽

Mild Conditions ◽

Wide Range ◽

Anthracene Derivatives

Anthracene derivatives have been used for a wide range of applications and many different synthetic methods for their preparation have been developed. However, despite continued synthetic efforts, introducing substituents in some positions has remained difficult. Here we present a method for the synthesis of 2,3,6,7-substituted anthracene derivatives, one of the most challenging anthracene substitution patterns to obtain. The method is exemplified by the preparation of 2,3,6,7-anthracenetetracarbonitrile and employs a newly developed, stable protected 1,2,4,5-benzenetetracarbaldehyde as the precursor. The precursor can be obtained in two scalable synthetic steps from 2,5-dibromoterephthalaldehyde and is converted into the anthracene derivative by a double intermolecular Wittig reaction under very mild conditions followed by a deprotection and intramolecular double ring-closing condensation reaction. Further modification of the precursor is expected to enable the introduction of additional substituents in other positions and may even enable the synthesis of fully substituted anthracene derivatives by the presented approach.<br>

Isomerization of the Isoprene Hydroxy Nitrates and Formation of Orthonitrite Compounds

10.26434/chemrxiv.8317127 ◽

2019 ◽

Author(s):

Gabriel da Silva

Keyword(s):

Hydroxy Group ◽

Peroxyl Radical ◽

Branching Fractions ◽

Membered Ring ◽

Low Energy ◽

Peroxyl Radicals ◽

Aerosol Formation ◽

Subsequent Removal ◽

Ring Compounds ◽

Group Migration

Atmospheric oxidation of isoprene produces significant yields of eight unique nitrate 11 compounds, each with a β- or δ-hydroxy group. These isoprene hydroxy nitrates (ISOPNs) 12 significantly impact upon global NOx budgets, O3 levels, and aerosol formation. 13 Uncertainties exist, however, in our understanding of ISOPN chemistry, particularly in their 14 yields from the reaction of isoprene peroxyl radicals with NO. This study describes novel 15 isomerization reactions of the ISOPNs, identified through the application of computational 16 chemistry techniques. These reactions produce saturated polycyclic orthonitrite compounds 17 via attack of the R–NO2 group on the vinyl moiety. For the δ-hydroxy nitrates, low-energy 18 isomerization pathways exist to six-membered ring compounds that are around 5 kcal mol-1 19 exothermic. These reactions proceed with barriers around 15 kcal mol-1 below the 20 respective peroxyl radical + NO reactants and yield orthonitrites that can further isomerize 21 to β-hydroxy ISOPNs. Moreover, the δ-hydroxy nitrates can directly interconvert with their β 22 substituted counterparts via NO3 group migration, with barriers that are lower yet. It follows 23 that β-hydroxy nitrates may be stabilized in the δ-hydroxy form, and vice versa. Moreover, 24 the lowest-energy pathway for dissociation of the δ-hydroxy ISOPNs is for the formation of 25 β-hydroxy alkoxyl radicals, and because of this established branching fractions between the 26 various isoprene peroxyl radicals may require re-evaluation. The results presented here also 27 suggest that ISOPNs may be stabilized to some extent in their saturated orthonitrite forms, 28 which has implications for both the total nitrate yield and for their subsequent removal by 29 OH, O3, and photolysis.<br><br>

Diversity-Oriented Synthetic Approaches for Furoindoline: A Review

10.2174/1570179416666190328211509 ◽

2019 ◽

Vol 16 (3) ◽

pp. 342-368 ◽

Cited By ~ 4

Author(s):

Ramandeep Kaur ◽

Yagyesh Kapoor ◽

Sundeep K. Manjal ◽

Ravindra K. Rawal ◽

Kapil Kumar

Keyword(s):

Rheumatoid Arthritis ◽

Cancer Cachexia ◽

Biological Activities ◽

Ring System ◽

Synthetic Methods ◽

Structural Units ◽

Current Article ◽

Tetrahydropyranyl Ether ◽

Synthetic Approaches ◽

Synthetic Target

The furo [2,3-b] indoline ring system is one of the most important structural units in various natural products. It has been known to have inherent biological activities and is utilized as a synthetic target for a number of natural compounds; therefore, this has contributed to a great demand for the growth of synthetic methods for this ring system. Most important compounds with furoindoline ring system are physovenine, madindoline A and B and makomotindoline etc. These compounds are well known to exhibit biological activity against different diseases such as glaucoma, cancer, cachexia, Castleman’s disease, rheumatoid arthritis, etc. The current article focuses on various synthetic approaches for furoindoline containing compounds and essential furoindoline moiety, such as oxindole-5-O-tetrahydropyranyl ether route etc., and various other diastereoand enantio- controlled approach in a very concise way.

The chemistry of 4-(dicyanomethylene)-3-methyl-l-phenyl-2-pyrazoline-5- ones as a privileged scaffold in synthesis of heterocycles

10.2174/1570179417666200924150340 ◽

2020 ◽

Vol 17 ◽

Author(s):

Mohsen A.-M. Gomaa ◽

Huda A. Ali

Keyword(s):

Building Block ◽

Heterocyclic Compounds ◽

Recent Progress ◽

Reaction Conditions ◽

Azacrown Ethers ◽

Wide Range ◽

Privileged Scaffold ◽

Number Of Publications ◽

Background : The reactivity of 4-(dicyanomethylene)-3-methyl-l-phenyl-2-pyrazoline-5-one DCNP 1 and its derivatives makes it valuable as a building block for the synthesis of heterocyclic compounds like pyrazolo-imidazoles, - thiazoles, spiropyridines, spiropyrroles, spiropyrans and others. As a number of publications have reported on the reactivity of DCNP and its derivatives, we compiled some features of this interesting molecule. Objective: This article aims to review the preparation of DCNP, its reactivity and application in heterocyclic and dyes synthesis. Conclusion: In this review we have provided an overview of recent progress in the chemistry of DCNP and its significance in synthesis of various classes of heterocyclic compounds and dyes. The unique reactivity of DCNP offers unprecedentedly mild reaction conditions for the generation of versatile cynomethylene dyes from a wide range of precursors including amines, α-aminocarboxylic acids, their esters, phenols, malononitriles and azacrown ethers. We anticipate that more innovative transformations involving DCNP will continue to emerge in the near future.

Using Satellite Data for CBRN (Chemical, Biological, Radiological, and Nuclear) Threat Detection, Monitoring, and Modelling

Surveys in Geophysics ◽

10.1007/s10712-021-09637-5 ◽

2021 ◽

Author(s):

Gary Sutlieff ◽

Lucy Berthoud ◽

Mark Stinchcombe

Keyword(s):

Satellite Data ◽

Meteorological Data ◽

Atmospheric Composition ◽

Chemical Detection ◽

List Type ◽

Data Types ◽

Wide Range ◽

Future Technologies ◽

The Impact ◽

Abstract CBRN (Chemical, Biological, Radiological, and Nuclear) threats are becoming more prevalent, as more entities gain access to modern weapons and industrial technologies and chemicals. This has produced a need for improvements to modelling, detection, and monitoring of these events. While there are currently no dedicated satellites for CBRN purposes, there are a wide range of possibilities for satellite data to contribute to this field, from atmospheric composition and chemical detection to cloud cover, land mapping, and surface property measurements. This study looks at currently available satellite data, including meteorological data such as wind and cloud profiles, surface properties like temperature and humidity, chemical detection, and sounding. Results of this survey revealed several gaps in the available data, particularly concerning biological and radiological detection. The results also suggest that publicly available satellite data largely does not meet the requirements of spatial resolution, coverage, and latency that CBRN detection requires, outside of providing terrain use and building height data for constructing models. Lastly, the study evaluates upcoming instruments, platforms, and satellite technologies to gauge the impact these developments will have in the near future. Improvements in spatial and temporal resolution as well as latency are already becoming possible, and new instruments will fill in the gaps in detection by imaging a wider range of chemicals and other agents and by collecting new data types. This study shows that with developments coming within the next decade, satellites should begin to provide valuable augmentations to CBRN event detection and monitoring. Article Highlights There is a wide range of existing satellite data in fields that are of interest to CBRN detection and monitoring. The data is mostly of insufficient quality (resolution or latency) for the demanding requirements of CBRN modelling for incident control. Future technologies and platforms will improve resolution and latency, making satellite data more viable in the CBRN management field

Applications of the Horner-Wadsworth-Emmons olefination in modern natural product synthesis

Synthesis ◽

10.1055/a-1493-6331 ◽

2021 ◽

Author(s):

Dávid Roman ◽

Maria Sauer ◽

Christine Beemelmanns

Keyword(s):

Natural Products ◽

Natural Product ◽

Natural Product Synthesis ◽

Reaction Conditions ◽

Comprehensive Review ◽

Modern Natural ◽

Key Steps ◽

Synthetic Approaches

Here, we have summarized more than 30 representative natural product syntheses published in 2015 to 2020 that employ one or more Horner-Wadsworth-Emmons (HWE) reactions. We comprehensively describe the applied phosphonate reagents, HWE reaction conditions and key steps of the total synthetic approaches. Our comprehensive review will support future synthetic approaches and serve as guideline to find the best HWE conditions for the most complicated natural products known

Low-valent dialkoxytitanium(ii): a useful tool for the synthesis of functionalized seven-membered ring compounds

Chemical Communications ◽

10.1039/d1cc00081k ◽

2021 ◽

Vol 57 (29) ◽

pp. 3603-3606

Author(s):

Florent Bodinier ◽

Youssouf Sanogo ◽

Janick Ardisson ◽

Marie-Isabelle Lannou ◽

Geoffroy Sorin

Keyword(s):

Grignard Reagent ◽

Membered Ring ◽

Ring Compounds ◽

Low Valent

Herein, we describe unprecedented access to all-carbon or heterocyclic seven-membered ring frameworks from 1,8-ene-ynes promoted by inexpensive low-valent titanium(ii) species, readily available from a combination of Ti(OiPr)4 and Grignard reagent.