scholarly journals Recent Developments in the Synthesis of Pyrido[1,2-a]benzimidazoles

Synthesis ◽  
2018 ◽  
Vol 50 (11) ◽  
pp. 2131-2149 ◽  
Author(s):  
Kamal Kapoor ◽  
Parthasarathi Das ◽  
Rajni Khajuria ◽  
Sk. Rasheed ◽  
Chhavi Khajuria
Keyword(s):  
Transition Metal ◽  
Medicinal Chemistry ◽  
Type I ◽  
Type Ii ◽  
Aromatic Rings ◽  
Metal Free ◽  
Wide Range ◽  
Recent Developments ◽  
Metal Catalyzed ◽  
Synthetic Approaches

Pyrido[1,2-a]benzimidazole is one of the most important azaheterocyclic compounds consisting of three fused aromatic rings. Molecules containing this core have displayed a wide range of applications in the field of medicinal chemistry. The synthesis of pyrido[1,2-a]benzimidazole and its derivatives has attracted organic chemists because of its tremendous utility in interdisciplinary branches of chemistry. In this context, this review discusses the main advances in the synthesis of pyrido[1,2-a]benzimidazoles via metal-mediated and metal-free reactions from 2000 to 2016.1 Introduction2 Synthetic Approaches to Pyrido[1,2-a]benzimidazoles2.1 Type I: Transition-Metal-Catalyzed Methods2.2 Type II: Metal-Free Approaches3 Conclusion

Five-Membered Hetarene N-Oxides: Recent Advances in Synthesis and Reactivity

Synthesis ◽  
2021 ◽  
Author(s):  
Leonid Fershtat ◽  
Fedor Teslenko
Keyword(s):  
Transition Metal ◽  
Medicinal Chemistry ◽  
Materials Science ◽  
State Of The Art ◽  
Short Review ◽  
Advanced Materials ◽  
Metal Free ◽  
Recent Advances ◽  
Application Potential ◽  
Metal Catalyzed

Five-membered heterocyclic N-oxides attracted special attention due to their strong application potential in medicinal chemistry and advanced materials science. In this regard, novel methods for their synthesis and functionalization are constantly required. In this short review, recent state-of-the-art achievements in the chemistry of isoxazoline N-oxides, 1,2,3-triazole 1-oxides and 1,2,5-oxadiazole 2-oxides are briefly summarized. Main routes to transition-metal-catalyzed and metal-free functionalization protocols along with mechanistic considerations are outlined. Transformation patterns of the hetarene N-oxide rings as precursors to other nitrogen heterocyclic systems are also presented.

Monodentate Trialkylphosphines: Privileged Ligands in Metal-catalyzed Crosscoupling Reactions

2020 ◽  
Vol 24 (3) ◽  
pp. 231-264 ◽  
Author(s):  
Kevin H. Shaughnessy
Keyword(s):  
Transition Metal ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Aryl Bromides ◽  
Wide Range ◽  
Sterically Demanding ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

Phosphines are widely used ligands in transition metal-catalyzed reactions. Arylphosphines, such as triphenylphosphine, were among the first phosphines to show broad utility in catalysis. Beginning in the late 1990s, sterically demanding and electronrich trialkylphosphines began to receive attention as supporting ligands. These ligands were found to be particularly effective at promoting oxidative addition in cross-coupling of aryl halides. With electron-rich, sterically demanding ligands, such as tri-tertbutylphosphine, coupling of aryl bromides could be achieved at room temperature. More importantly, the less reactive, but more broadly available, aryl chlorides became accessible substrates. Tri-tert-butylphosphine has become a privileged ligand that has found application in a wide range of late transition-metal catalyzed coupling reactions. This success has led to the use of numerous monodentate trialkylphosphines in cross-coupling reactions. This review will discuss the general properties and features of monodentate trialkylphosphines and their application in cross-coupling reactions of C–X and C–H bonds.

scholarly journals Recent Advances in Transition-Metal-Free (4+3)-Annulations

Synthesis ◽  
2021 ◽  
Author(s):  
Heather Lam ◽  
Mark Lautens ◽  
Xavier Abel-Snape ◽  
Martin F. Köllen
Keyword(s):  
Transition Metal ◽  
Boronic Acid ◽  
Lewis Acids ◽  
Acid Catalysis ◽  
Heterocyclic Carbenes ◽  
Bronsted Acids ◽  
Metal Free ◽  
Previous Review ◽  
Dual Activation ◽  
Metal Catalyzed

Abstract(4+3)-Annulations are incredibly versatile reactions which combine a 4-atom synthon and a 3-atom synthon to form both 7-membered carbocycles as well as heterocycles. We have previously reviewed transition-metal-catalyzed (4+3)-annulations. In this review, we will cover examples involving bases, NHCs, phosphines, Lewis and Brønsted acids as well as some rare examples of boronic acid catalysis and photocatalysis. In analogy to our previous review, we exclude annulations involving cyclic dienes like furan, pyrrole, cyclohexadiene or cyclopentadiene, as Chiu, Harmata, Fernándes and others have recently published reviews encompassing such substrates. We will however discuss the recent additions (2010–2020) to the literature on (4+3)-annulations involving other types of 4-atom-synthons.1 Introduction2 Bases3 Annulations Using N-Heterocyclic Carbenes3.1 N-Heterocyclic Carbenes (NHCs)3.2 N-Heterocyclic Carbenes and Base Dual-Activation4 Phosphines5 Acids5.1 Lewis Acids5.2 Brønsted Acids6 Boronic Acid Catalysis and Photocatalysis7 Conclusion

Reactions of secondary propargylamines with heteroallenes for the synthesis of diverse heterocycles

2018 ◽  
Vol 47 (11) ◽  
pp. 3861-3898 ◽  
Author(s):  
Vsevolod A. Peshkov ◽  
Olga P. Pereshivko ◽  
Anton A. Nechaev ◽  
Anatoly A. Peshkov ◽  
Erik V. Van der Eycken
Keyword(s):  
Transition Metal ◽  
Recent Developments ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

This focused review aims to summarize recent developments in the processes involving additions of secondary propargylamines to various heteroallenes and subsequent transition metal-catalyzed or electrophile-mediated cyclizations.

scholarly journals Pd-Catalyzed Cross-Electrophile Coupling/C–H Alkylation Reaction Enabled by a Mediator Generated via C(sp3)–H Activation

2021 ◽  
Author(s):  
Zhuo Wu ◽  
Hang Jiang ◽  
Yanghui Zhang
Keyword(s):  
Transition Metal ◽  
Alkyl Group ◽  
Alkylation Reaction ◽  
Aromatic Rings ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed ◽  
Alkylation Reactions

Transition-metal-catalyzed cross-electrophile C(sp2)–(sp3) coupling and C–H alkylation reactions represent two efficient methods for the incorpration of an alkyl group into aromatic rings. Herein, we report a Pd-catalyzed cascade cross-electrophile coupling...

Recent advance in ester synthesis by Multi Component Reactions (MCRs): A Review

2021 ◽  
Vol 25 ◽  
Author(s):  
Dhaval B. Patel ◽  
Jagruti A. Parmar ◽  
Siddharth S. Patel ◽  
Unnati J. Naik ◽  
Hitesh D. Patel
Keyword(s):  
Multicomponent Reactions ◽  
Medicinal Chemistry ◽  
Reaction Times ◽  
Synthetic Methods ◽  
Ester Synthesis ◽  
One Pot ◽  
Wide Range ◽  
Recent Developments ◽  
Ester Linkage ◽  
The One

: The synthesis of ester containing heterocyclic compounds via multicomponent reaction is one of the most preferable process in the synthetic organic chemistry and medicinal chemistry. Compounds containing ester linkage have a wide range of biological application in the pharmaceutical field. Therefore, many method have been developed for the synthesis of these type of derivatives. However, some of them are carried out in the presence of toxic solvents and catalysts, with lower yields, longer reaction times, low selectivities and by-products. Thus, the development of new synthetic methods for the ester synthesis is required in the medicinal chemistry. As we know, multicomponent reactions (MCRs) are a powerful tool towards the one-pot ester synthesis, so in this article we have reviewed the recent developments in ester synthesis. This work covers selected explanation of methods via multicomponent reactions to explore the methodological development in ester synthesis.

Transition-Metal-Free Catalysis for the Reductive ­Functionalization of CO2 with Amines

Synlett ◽  
2018 ◽  
Vol 29 (05) ◽  
pp. 548-555 ◽  
Author(s):  
Liang-Nian He ◽  
Xiao-Fang Liu ◽  
Xiao-Ya Li ◽  
Chang Qiao
Keyword(s):  
Transition Metal ◽  
Energy Content ◽  
Bond Formation ◽  
Energy Storage Materials ◽  
One Pot ◽  
Metal Free ◽  
Recent Developments ◽  
Electron Reduction ◽  
Reduction Of Co2 ◽  
Hierarchical Reduction

Reductive functionalization of CO2 with amines and a reductant, which combines both reduction of CO2 and C–N bond formation in one pot to produce versatile chemicals and energy-storage materials such as formamides, aminals, and methylamines that are usually derived from petroleum feedstock, would be appealing and promising. Herein, we give a brief review on recent developments in the titled CO2 chemistry by employing transition-metal-free catalysis, which can be catalogued as below according to the diversified energy content of the products, that is formamides, aminals, and methylamines being consistent with 2-, 4-, and 6-electron reduction of CO2, respectively. Notably, hierarchical reduction of CO2 with amines to afford at least two products, for example, formamides and methylamines, could be realized with the same catalyst through tuning the hydrosilane type, reaction temperature, or CO2 pressure. Finally, the opportunities and challenges of the reductive functionalization of CO2 with amines are also highlighted.1 Introduction2 2-Electron Reduction of CO2 to Formamide3 6-Electron Reduction of CO2 to Methylamine4 4-Electron Reduction of CO2 to Aminal5 Hierarchical Reduction of CO2 with Amines6 Conclusion

scholarly journals Advances in the Preparation of Fluorinated Isoquinolines: A Decade of Progress

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Joseph C. Sloop
Keyword(s):  
Transition Metal ◽  
Functional Groups ◽  
Synthetic Methods ◽  
Ring Systems ◽  
Heterocyclic Molecules ◽  
The Past ◽  
Ring Assembly ◽  
Metal Catalyzed ◽  
Synthetic Approaches ◽  
Isoquinoline Derivatives

Heterocyclic molecules incorporating fluorinated isoquinoline components are found in many medicinally and agriculturally important bioactive products as well as industrially impactful materials. Within the past decade, a variety of isoquinolinic ring assembly techniques has enabled the introduction of diverse fluorine-containing functionalities which can enhance potential bioactivity and industrial utility. This review examines recent noncatalyzed and transition metal catalyzed synthetic approaches to the assembly of isoquinoline derivatives that are ring-fluorinated and/or result in the incorporation of fluorine-containing functional groups. Specifically, efficient synthetic methods and regioselectivity in the incorporation of functional groups into isoquinoline ring systems are examined.

scholarly journals Cancer Biology and Prevention in Diabetes

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1380 ◽  
Author(s):  
Swayam Prakash Srivastava ◽  
Julie E. Goodwin
Keyword(s):  
Type Ii Diabetes ◽  
Cancer Biology ◽  
Cancer Metastasis ◽  
Type I Diabetes ◽  
Type I ◽  
Type Ii ◽  
Mesenchymal Transition ◽  
Wide Range ◽  
Risk Of Cancer

The available evidence suggests a complex relationship between diabetes and cancer. Epidemiological data suggest a positive correlation, however, in certain types of cancer, a more complex picture emerges, such as in some site-specific cancers being specific to type I diabetes but not to type II diabetes. Reports share common and differential mechanisms which affect the relationship between diabetes and cancer. We discuss the use of antidiabetic drugs in a wide range of cancer therapy and cancer therapeutics in the development of hyperglycemia, especially antineoplastic drugs which often induce hyperglycemia by targeting insulin/IGF-1 signaling. Similarly, dipeptidyl peptidase 4 (DPP-4), a well-known target in type II diabetes mellitus, has differential effects on cancer types. Past studies suggest a protective role of DPP-4 inhibitors, but recent studies show that DPP-4 inhibition induces cancer metastasis. Moreover, molecular pathological mechanisms of cancer in diabetes are currently largely unclear. The cancer-causing mechanisms in diabetes have been shown to be complex, including excessive ROS-formation, destruction of essential biomolecules, chronic inflammation, and impaired healing phenomena, collectively leading to carcinogenesis in diabetic conditions. Diabetes-associated epithelial-to-mesenchymal transition (EMT) and endothelial-to-mesenchymal transition (EndMT) contribute to cancer-associated fibroblast (CAF) formation in tumors, allowing the epithelium and endothelium to enable tumor cell extravasation. In this review, we discuss the risk of cancer associated with anti-diabetic therapies, including DPP-4 inhibitors and SGLT2 inhibitors, and the role of catechol-o-methyltransferase (COMT), AMPK, and cell-specific glucocorticoid receptors in cancer biology. We explore possible mechanistic links between diabetes and cancer biology and discuss new therapeutic approaches.

Deuterated Aryl Alkyl Ethers Synthesis via Nucleophilic Etherification of Aryl Alkyl Ethers and Thioethers with Deuterated Alcohols

Synlett ◽  
2019 ◽  
Vol 30 (15) ◽  
pp. 1805-1809
Author(s):  
Shuai Li ◽  
Xia Wang ◽  
Xin-Ge Yang ◽  
Gui-Quan Yu ◽  
Xue-Qiang Wang
Keyword(s):  
Transition Metal ◽  
Nucleophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Metal Free ◽  
Wide Range ◽  
Alkyl Ethers

A transition-metal-free etherification protocol that is capable of synthesizing deuterated ethers is described. A wide range of aryl alkyl ethers and thioethers were suitable for this transformation owing to the mild reaction conditions. Besides, a series of sterically bulky deuterated alcohols were successfully incorporated into cyano-substituted arenes. The results of mechanistic studies suggested this reaction might take place via nucleophilic aromatic substitution pathway.

Sign in / Sign up

Export Citation Format

Share Document