scholarly journals Synthesis and Biological Activities of Pyrazino[1,2-a]indole and Pyrazino[1,2-a]indol-1-one Derivatives

2021 ◽  
Vol 14 (8) ◽  
pp. 779
Author(s):  
Kena Zhang ◽  
Christine Tran ◽  
Mouad Alami ◽  
Abdallah Hamze ◽  
Olivier Provot
Keyword(s):  
Biological Activity ◽  
Biological Activities ◽  
Metal Catalysts ◽  
Point Of View ◽  
Cyclization Reactions ◽  
Metal Free ◽  
Michael Reactions ◽  
Anti Cancer ◽  
Synthetic Routes ◽  
Metal Catalyzed

This review concerns the synthesis and biological activities of pyrazino[1,2-a]indoles and pyrazino[1,2-a]indol-1-ones reported since 1997 and the discovery of biological activity of pyrazinoindole derivatives. In the first part, we first presented the synthetic routes that have been reported from a methodological point of view to access the pyrazinoindole unit according to cyclization reactions using or not using metal catalysts. Then, syntheses and neuropsychiatric, auto-immune, anti-infectious and anti-cancer properties of pyrazinoindoles were detailed. In the second part, we first reported the main accesses to pyrazinoindol-1-one substrates according to Michael reactions, metal-catalyzed and metal-free cyclization reactions. The syntheses and anti-cancer, anti-infectious, anti-allergenic and neuropsychiatric properties of pyrazinoindolones were next described and discussed.

scholarly journals A cascade double 1,4-addition/intramolecular annulation strategy for expeditious assembly of unsymmetrical dibenzofurans

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xinwei He ◽  
Ruxue Li ◽  
Pui Ying Choy ◽  
Mengqing Xie ◽  
Jiahui Duan ◽  
...  
Keyword(s):  
Transition Metal ◽  
Late Stage ◽  
Functional Group ◽  
Conjugate Addition ◽  
Carbon Structure ◽  
Metal Free ◽  
Air Atmosphere ◽  
Efficient Access ◽  
Synthetic Routes ◽  
Metal Catalyzed

AbstractExisting synthetic routes for accessing dibenzofuran core have intrinsic regioselectivity, limiting the substitution patterns available in heteropolycyclic arene products. Here we report a double 1,4-conjugate addition/intramolecular annulation cascade reaction between propargylamines and two equivalents of imidazolium methylides that allows efficient access of structurally versatile dibenzofurans. This transition metal-free protocol proceeds smoothly under bench-top air atmosphere and offers easy manipulation of substituents on the dibenzofuran core, and also provides good-to-excellent product yields with good functional group tolerance, particularly the –Br and –Cl groups which are often incompatible with existing metal-catalyzed C–C and/or C–O bond ring-forming processes. It is worth noting that ladder-type π-systems with all-arene quarternary carbon structure can be straightforwardly generated upon simple late-stage functionalization.

scholarly journals Synthesis, Modification and Biological Activity of Diosgenyl β-d-Glycosaminosides: An Overview

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5433
Author(s):  
Daria Grzywacz ◽  
Beata Liberek ◽  
Henryk Myszka
Keyword(s):  
Biological Activity ◽  
Biological Activities ◽  
Protecting Groups ◽  
Pharmacological Properties ◽  
Amino Group ◽  
Reaction Conditions ◽  
Naturally Occurring ◽  
Anti Cancer ◽  
Wide Group ◽  
Derivatives Of

Saponins are a structurally diverse class of natural glycosides that possess a broad spectrum of biological activities. They are composed of hydrophilic carbohydrate moiety and hydrophobic triterpenoid or steroid aglycon. Naturally occurring diosgenyl glycosides are the most abundant steroid saponins, and many of them exhibit various pharmacological properties. Herein, we present an overview of semisynthetic saponins syntheses–diosgenyl β-d-glycosaminosides (d-gluco and d-galacto). These glycosides possess a 2-amino group, which creates great possibilities for further modifications. A wide group of glycosyl donors, different N-protecting groups and various reaction conditions used for their synthesis are presented. In addition, this paper demonstrates the possibilities of chemical modifications of diosgenyl β-d-glycosaminosides, associated with functionalisation of the amino group. These provide N-acyl, N-alkyl, N,N-dialkyl, N-cinnamoyl, 2-ureido and 2-thiosemicarbazonyl derivatives of diosgenyl β-d-glycosaminosides, for which the results of biological activity tests (antifungal, antibacterial, anti-cancer and hemolytic) are presented.

Recent Developments on Denitrogenative Functionalization of Benzotriazoles

Synthesis ◽  
2020 ◽  
Vol 52 (24) ◽  
pp. 3781-3800
Author(s):  
Guobing Yan ◽  
Vinod K. Tiwari ◽  
Jie Yu ◽  
Anoop S. Singh ◽  
Jian Yu
Keyword(s):  
Short Review ◽  
Structural Motif ◽  
Easy Access ◽  
Coupling Reactions ◽  
Future Perspectives ◽  
Cyclization Reactions ◽  
Recent Developments ◽  
Synthetic Routes ◽  
Metal Catalyzed ◽  
Benzotriazole Derivatives

AbstractBenzotriazoles are employed as useful synthons in organic synthesis, and due to their unique structural motif, they are able to undergo denitrogenation during the construction of new bonds. Various methods for the functionalization of benzotriazoles as precursors of ­ortho-amino arenediazoniums have recently been developed that involve transition-metal-catalyzed coupling reactions, mainly via cyclization, borylation, alkenylation, alkylation, carbonylation and the formation of carbon–heteroatom bonds. In this short review, we primarily focus on the recent applications of benzotriazoles in organic chemistry that proceed via a denitrogenative process, and the mechanisms are also discussed.1 Introduction2 Common Synthetic Routes Allowing Easy Access to Benzotriazole Derivatives3 Formation of C–C Bonds3.1 Cyclization Reactions3.2 Arylation, Alkenylation, Alkylation and Carbonylation Reactions4 Carbon–Heteroatom Bond Formation5 Miscellaneous Denitrogenative Functionalization6 Conclusions and Future Perspectives

scholarly journals 2,3-Dehydroderivatives of Silymarin Flavonolignans: Prospective Natural Compounds for the Prevention of Chronic Diseases

Proceedings ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 21 ◽  
Author(s):  
Kateřina Valentová ◽  
David Biedermann ◽  
Vladimír Křen
Keyword(s):  
Biological Activity ◽  
Chronic Diseases ◽  
Biological Activities ◽  
Natural Compounds ◽  
Oxidation Products ◽  
Radical Scavengers ◽  
Silybum Marianum ◽  
Fruit Extract ◽  
Anti Cancer

Silybum marianum fruit extract silymarin displays various biological activities, which are attributed mostly to its major component silybin. However, silymarin contain several other isomeric flavonolignans (isosilybin, silychristin, silydianin) and their oxidation products, the 2,3-dehydroflavonolignans (2,3-dehydrosilybin, 2,3-dehydrosilychristin, 2,3-dehydrosilydianin). The latter compounds were found to be 1-2 orders of magnitude more efficient radical scavengers, reducing, chelating, cytoprotective, anti-aging, anti-cancer and anti-angiogenic agents than the parent flavonolignans. Although 2,3-dehydroflavonolignans occur in silymarin as minorities, they seem to be responsible for the majority of the biological activity and therefore have potential for the prevention of chronic diseases.

Recent Developments in the Synthesis of Cinnoline Derivatives

2019 ◽  
Vol 16 (6) ◽  
pp. 578-588 ◽  
Author(s):  
Kamal Usef Sadek ◽  
Ramadan Ahmed Mekheimer ◽  
Mohamed Abd-Elmonem
Keyword(s):  
Reaction Mechanisms ◽  
Biological Activities ◽  
Bond Formation ◽  
Pharmaceutical Chemistry ◽  
Recent Developments ◽  
Synthetic Routes ◽  
Anti Inflammatory ◽  
Arenediazonium Salts ◽  
Metal Catalyzed ◽  
Bond Formation Reactions

Crinnolines can serve as unique and versatile class of heterocycles especially in fields related to synthetic and pharmaceutical chemistry owing to their potent biological activities. They possess diversity of pharmaceutical activities as anticancer, antibacterial, anti-inflammatory, anti-allergic as well as anti-hypertensive activities. Since the first synthesis of cinnoline by Richter (1883) numerous protocols for their synthesis have been developed utilizing arenediazonium salts, aryl hydrazines and arylhydhydrazones precursors. Recently metal catalyzed C-C and C-N bond formation reactions have emerged as efficient tools for synthesis of cinnoline derivatives. This review aims to focus on the recent synthetic routes used for the synthesis of cinnoline derivatives. An effort has been carried out to provide an overview of practical methods for preparing cinnolines. Furthermore the reaction mechanisms have been described in brief.

Transition-Metal-Free Functionalization of Saturated and Unsaturated Amines to Bioactive Alkaloids Mediated by Sodium Chlorite

Synlett ◽  
2020 ◽  
Author(s):  
Fernando Sartillo-Piscil ◽  
Julio Romero-Ibañez ◽  
Lilia Fuentes
Keyword(s):  
Transition Metal ◽  
Precious Metals ◽  
Extraction Process ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Sodium Chlorite ◽  
Chemical Transformations ◽  
Metal Free ◽  
Cyclic Amines ◽  
Metal Catalyzed

AbstractNew approaches to the synthesis of alkaloids through the straightforward functionalization of C(sp3)–H and C(sp2)=C(sp2) bonds of simple five- and six-membered-ring N-heterocycles are highlighted. The direct functionalization of pre-existing N-heterocycles to advanced alkaloids intermediates is a chemical operation that commonly requires the intervention of transition or precious metals. Regardless the inherent unwanted waste production, the high economical cost of many transition-metal catalysts limits their use globally. Here, we account our efforts directed toward the synthesis of bioactive alkaloids under an economic and ecological fashion by using NaClO2 as the key activating or oxidizing reagent that substitutes the use of transition-metal catalysts. While undesired metal wastes are collected during the extraction process of a transition-metal-catalyzed reaction, innocuous NaCl is the commonly product waste when NaClO2 is employed in our chemical transformations. Beginning with the synthesis of 2,3-epoxyamides from allyl amines, we concluded with the functionalization of multiple and remote C(sp3)–H and C(sp3)–C(sp3) bonds in piperidine rings that enabled the preparation of important bioactive alkaloids. For the latter functionalization, a precise amount of co-oxidant reagent (NaOCl) and radical 2,2,6,6-tetramethylpiperidinyloxy (TEMPO) were needed.1 Introduction2 Direct Chemical Method for Preparing 2,3-Epoxyamides3 Dual C(sp3)–H Oxidation of Cyclic Amines to 3‑Alkoxyamine Lac­tams4 Electrochemical Deamination of 3-Alkoxyamine Lactams5 Direct C–H Oxidation of Piperazines and Morpholines to 2,3-Diketopiperazines and 3-Morpholinones, Respectively6 Transition-Metal-Free Triple C–H Oxidation7 Deconstructive Lactamization of Piperidines8 Conclusion

Three-Component [1+1+1] Cyclopropanation with Ruthenium(II)

2018 ◽  
Author(s):  
Tanner C. Jankins ◽  
Robert R. Fayzullin ◽  
Eugene Khaskin
Keyword(s):  
Quaternary Carbon ◽  
Poor Control ◽  
One Step ◽  
Synthetic Routes ◽  
Mechanistic Investigations ◽  
Chiral Centers ◽  
Metal Catalyzed ◽  
The Right ◽  
Substituted Cyclopropanes

We report a one-step, Ru(II)-catalyzed cyclopropanation reaction that is conceptually different from the previously reported protocols that include Corey-Chaykovsky, Simmons-Smith, and metal catalyzed carbene attack on olefins. Under the current protocol, various alcohols are transformed into sulfone substituted cyclopropanes with excellent isolated yields and diastereoselectivities. This new reaction forms highly congested cyclopropane products with three new C–C bonds, three or two new chiral centers and one new quaternary carbon center. 22 examples of isolated substrates are given. Previously reported synthetic routes for similar substrates are all multi-step, linear routes that proceed with overall low yields and poor control of stereochemistry. Experimental mechanistic investigations suggest initial metal-catalyzed dehydrogenation of the alcohol substrate and catalyst independent stepwise attack of two equivalents of sulfone on the aldehyde under basic conditions. While the Ru(II) is only responsible for the initial dehydrogenation step, the rate of aldehyde formation is crucial to maintaining the right balance of intermediates needed to afford the cyclopropane product.

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