Construction of N-heterocycles via Pd-mediated C–H activation/annulation strategies

2022 ◽  
Author(s):  
Mengyu Qiu ◽  
Xuegang Fu ◽  
Peng Fu ◽  
Jianhui Huang
Keyword(s):  
Natural Products ◽  
Organic Synthesis ◽  
Material Science ◽  
Medicinal Chemistry ◽  
Drug Molecules

N-heterocycles can be found in natural products and drug molecules, which are indispensable components in the area of organic synthesis, medicinal chemistry and material science. The construction of these N-containing...

scholarly journals Synthetic Strategies in the Preparation of Phenanthridinones

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5560
Author(s):  
Rajeshwar Reddy Aleti ◽  
Alexey A. Festa ◽  
Leonid G. Voskressensky ◽  
Erik V. Van der Eycken
Keyword(s):  
Natural Products ◽  
Organic Synthesis ◽  
Medicinal Chemistry ◽  
Coupling Reactions ◽  
Structural Importance ◽  
Wide Range ◽  
Biaryl Coupling ◽  
Synthetic Methodologies

Phenanthridinones are important heterocyclic frameworks present in a variety of complex natural products, pharmaceuticals and displaying wide range of pharmacological actions. Its structural importance has evoked a great deal of interest in the domains of organic synthesis and medicinal chemistry to develop new synthetic methodologies, as well as novel compounds of pharmaceutical interest. This review focuses on the synthesis of phenanthridinone scaffolds by employing aryl-aryl, N-aryl, and biaryl coupling reactions, decarboxylative amidations, and photocatalyzed reactions.

The Synthesis of Amides through Direct Amination of Aldehydes with Amines

2019 ◽  
Vol 23 (8) ◽  
pp. 901-919 ◽  
Author(s):  
Yaorui Ma ◽  
Junfei Luo
Keyword(s):  
Natural Products ◽  
Organic Synthesis ◽  
Material Science ◽  
Catalyst System ◽  
Fundamental Groups ◽  
Direct Amination ◽  
Amide Bonds ◽  
The Past ◽  
Amide Synthesis ◽  
The Future

Amide bonds are amongst the most fundamental groups in organic synthesis, and they are widely found in natural products, pharmaceuticals and material science. Over the past decade, methods for the direct amination of aldehydes have received much attention as they represent atom- and step-economic routes for amide synthesis from readily available starting materials. Herein, the research advances on the direct amination of aldehydes are reviewed and categorized by the types of catalyst system. Detailed reaction scopes and mechanisms will be discussed, as well as the limitations of current procedures and the prospects for the future.

Regioselective Synthesis of Diverse Thio-, Seleno-substituted 1,2,3-Triazoles

2020 ◽  
Vol 23 (22) ◽  
pp. 2379-2401
Author(s):  
Lin-Lin Zhang ◽  
Qin-Pei Wu ◽  
Zhi-Bin Xu
Keyword(s):  
Organic Synthesis ◽  
Reaction Mechanisms ◽  
Material Science ◽  
Medicinal Chemistry ◽  
Synthetic Methods ◽  
Regioselective Synthesis ◽  
Internal Alkynes ◽  
Synthetic Approaches

: Thio-, seleno-substituted triazoles are useful scaffolds employed in the fields of organic synthesis, medicinal chemistry, and material science. A number of synthetic approaches to efficient formation of thio- and seleno-triazoles have been disclosed, including the interception of copper(I) triazolides generated in-situ, cycloaddition of internal alkynes (thio-, halo-, and metalated alkynes) to azides, and the coupling of azides and nonalkyne substrates. This mini-review intends to summarize the synthetic methods toward thio-, seleno-1,2,3-triazoles and the relative reaction mechanisms.

scholarly journals A Novel Dual Organocatalyst for the Asymmetric Pinder Reaction and a Mechanistic Proposal Consistent with the Isoinversion Effect Thereof

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6398
Author(s):  
Fotini Moschona ◽  
Athena Vagena ◽  
Veroniki P. Vidali ◽  
Gerasimos Rassias
Keyword(s):  
Natural Products ◽  
Transition State ◽  
Organic Synthesis ◽  
Lewis Acid ◽  
Medicinal Chemistry ◽  
Aromatic Aldehydes ◽  
Bioactive Molecules ◽  
Knoevenagel Reaction ◽  
Chiral Centers

In general, the Pinder reaction concerns the reaction between an enolisable anhydride and an aldehyde proceeding initially through a Knoevenagel reaction followed by the ring closing process generating lactones with at least two chiral centers. These scaffolds are frequently present in natural products and synthetic bioactive molecules, hence it has attracted intense interest in organic synthesis and medicinal chemistry, particularly with respect to controlling the diastereo- and enantioselectivity. To the best of our knowledge, there has been only one attempt prior to this work towards the development of a catalytic enantioselective Pinder reaction. In our approach, we designed, synthesized, and tested dual chiral organocatalysts by combining BIMAH amines, (2-(α-(alkyl)methanamine)-1H-benzimidazoles, and a Lewis acid motif, such as squaramides, ureas and thioureas. The optimum catalyst was the derivative of isopropyl BIMAH bearing a bis(3,5-trifluoromethyl) thiourea, which afforded the Pinder products from various aromatic aldehydes with diastereomeric ratio >98:2 and enatioselectivity up to 92 ee%. Interestingly, the enantioselectivity of this catalyzed process is increased at higher concentrations and exhibits an isoinversion effect, namely an inverted "U" shaped dependency with respect to the temperature. Mechanistically, these features, point to a transition state involving an entropy-favored heterodimer interaction between a catalyst/anhydride and a catalyst/aldehyde complex when all other processes leading to this are much faster in comparison above the isoinversion temperature.

Cascade CuH-Catalyzed Conversion of Alkynes to Enantioenriched 1,1-Disubstituted Products

2019 ◽  
Author(s):  
De-Wei Gao ◽  
Yang Gao ◽  
Huiling Shao ◽  
Tian-Zhang Qiao ◽  
Xin Wang ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Medicinal Chemistry ◽  
Proteasome Inhibitors ◽  
Building Blocks ◽  
Unique Role ◽  
Efficient Strategy ◽  
Carbon Centers ◽  
Rapid Access ◽  
Cascade Catalysis ◽  
Privileged Scaffolds

Enantioenriched <i>α</i>-aminoboronic acids play a unique role in medicinal chemistry and have emerged as privileged pharmacophores in proteasome inhibitors. Additionally, they represent synthetically useful chiral building blocks in organic synthesis. Recently, CuH-catalyzed asymmetric alkene hydrofunctionalization has become a powerful tool to construct stereogenic carbon centers. In contrast, applying CuH cascade catalysis to achieve reductive 1,1-difunctionalization of alkynes remains an important, but largely unaddressed, synthetic challenge. Herein, we report an efficient strategy to synthesize <i>α</i>-aminoboronates <i>via </i>CuH-catalyzed hydroboration/hydroamination cascade of readily available alkynes. Notably, this transformation selectively delivers the desired 1,1-heterodifunctionalized product in favor of alternative homodifunctionalized, 1,2-heterodifunctionalized, or reductively monofunctionalized byproducts, thereby offering rapid access to these privileged scaffolds with high chemo-, regio- and enantioselectivity.<br>

Catalytic, Enantioselective Syn-Diamination of Alkenes

2019 ◽  
Author(s):  
Zhonglin Tao ◽  
Brad Gilbert ◽  
Scott Denmark
Keyword(s):  
General Solution ◽  
Organic Synthesis ◽  
Medicinal Chemistry ◽  
Catalytic Cycle ◽  
Bifunctional Nucleophile

The enantioselective, vicinal diamination of alkenes represents one of the stereocontrolled additions that remains an outstanding challenge in organic synthesis. A general solution to this problem would enable the efficient and selective preparation of widely useful, enantioenriched diamines for applications in medicinal chemistry and catalysis. In this Article we describe the first enantioselective, <i>syn-</i>diamination of simple alkenes mediated by a chiral, enantioenriched organoselenium catalyst together with a <i>N,N’-</i>bistosyl urea as the bifunctional nucleophile and <i>N-</i>fluorocollidinium tetrafluoroborate as the stoichiometric oxidant. Diaryl, aryl-alkyl, and alkyl-alkyl olefins bearing a variety of substituents are all diaminated in consistently high enantioselectivities selectivities but variable yields. The reaction likely proceeds through a Se(II)/Se(IV) redox catalytic cycle reminiscent of the <i>syn-</i>dichlorination reported previously. Furthermore, the <i>syn</i>-stereospecificity of the transformation shows promise for highly enantioselective diaminations of alkenes with no strong steric or electronic bias.

Enantioselective Syntheses of Flavonoid Diels-Alder Natural Products: A Review

2018 ◽  
Vol 15 (2) ◽  
pp. 221-229 ◽  
Author(s):  
Shah Bakhtiar Nasir ◽  
Noorsaadah Abd Rahman ◽  
Chin Fei Chee
Keyword(s):  
Natural Products ◽  
Organic Synthesis ◽  
Lewis Acid ◽  
Alder Reaction ◽  
Diels Alder ◽  
Enantioselective Synthesis ◽  
Chiral Ligand ◽  
Asymmetric Syntheses ◽  
Diels Alder Reaction ◽  
Enantioselective Syntheses

Background: The Diels-Alder reaction has been widely utilised in the syntheses of biologically important natural products over the years and continues to greatly impact modern synthetic methodology. Recent discovery of chiral organocatalysts, auxiliaries and ligands in organic synthesis has paved the way for their application in Diels-Alder chemistry with the goal to improve efficiency as well as stereochemistry. Objective: The review focuses on asymmetric syntheses of flavonoid Diels-Alder natural products that utilize chiral ligand-Lewis acid complexes through various illustrative examples. Conclusion: It is clear from the review that a significant amount of research has been done investigating various types of catalysts and chiral ligand-Lewis acid complexes for the enantioselective synthesis of flavonoid Diels-Alder natural products. The results have demonstrated improved yield and enantioselectivity. Much emphasis has been placed on the synthesis but important mechanistic work aimed at understanding the enantioselectivity has also been discussed.

Crown Ether—Pillararenes Hybrid Macrocyclic System

2021 ◽  
Author(s):  
Zhaona Liu ◽  
Huacheng Zhang ◽  
Jie Han
Keyword(s):  
Crown Ether ◽  
Hybrid Systems ◽  
Organic Synthesis ◽  
Material Science ◽  
Planar Chirality ◽  
System P ◽  
Structural Architecture ◽  
Macrocyclic System

Combination of Nobel macrocycle—crown ether and star macrocycle—pillararenes together in organic synthesis and material science is significant to grant thus obtained hybrid systems, rigid/flexible structural architecture, induced planar chirality, negative...

Recent Advances on Small Molecule Medicinal Chemistry to Treat Human Diseases-Part III

2021 ◽  
Vol 21 (17) ◽  
pp. 1517-1518
Author(s):  
Dharmendra Kumar Yadav
Keyword(s):  
Natural Products ◽  
Drug Discovery ◽  
Small Molecule ◽  
Anticancer Agents ◽  
Medicinal Chemistry ◽  
Review Article ◽  
Human Diseases ◽  
Bioactive Metabolite ◽  
Metabolite Production ◽  
Life Threatening

The discovery and utilization of novel metabolites from natural sources are gaining momentum in the present era. The drug discovery programs have witnessed a remarkable shift from conventional medicines to exploiting natural products and their “value addition”, for treating lifethreatening diseases. The global outbreak of life-threatening diseases namely Ebola, SARS,including infections of the bloodstream (bacteremia), heart valves (endocarditis), lungs (pneumonia), and brain (meningitis) and AIDS calls for a more targeted approach to effectively combat the emerging diseases. In the present scenario, natural products and their extracts are being explored extensively for the treatment of various life threatening diseases. In this thematic issue, several review articles contributed by the scientist and researchers in the different areas of medicinal chemistry, synthetic chemistry, new emerging multi-drug targets were collected. This issue begins with a review article on the “Chemistry and Pharmacology of Natural Catechins from Camellia sinensis as anti-MRSA agents” by Gaur et al. and focuses on the spread of MRSA strains is of great concern because of limited treatment options for staphylococcal infections, since these strains are resistant to the entire class of β-lactam antibiotics. In addition, MRSA exhibits resistance to other classes of antimicrobial agents such as fluoroquinolones, cephalosporins, aminoglycosides, macrolide and even glycopeptides (vancomycin and teicoplanine), leading to the emergence of resistant strains such as glycopeptide intermediate (GISA) and resistant strain (GRSA) of S. aureus. In this review, chemical constituents responsible for the anti-MRSA activity of tea are explored [1]. The next article of this issue is a review article on the “Recent Advancements in the Synthesis and Chemistry of Benzofused Nitrogen- and Oxygen-based Bioactive Heterocycles” by Sharma et al. which focuses on medicinal importance of these bioactive benzo-fused heterocycles; special attention has been given to their synthesis as well as medicinal/pharmaceutical properties in detail [2]. “Trends in pharmaceutical design of Endophytes as anti-infective,” by Tiwari et al., is the third article in this issue. The review focused on the meta-analysis of bioactive metabolite production from endophytes, extensively discussing the bioprospection of natural products for pharmaceutical applications. In light of the emerging importance of endophytes as antiinfective agents, an exploration of the pharmaceutical design of novel chemical entities and analogues has enabled efficient and cost-effective drug discovery programs. However, bottlenecks in endophytic biology and research requires a better understanding of endophytic dynamics and mechanism of bioactive metabolite production towards a sustainable drug discovery program [3]. The last article of this issue is also research article on “Recent development of tetrahydro-quinoline/isoquinoline based compounds as anticancer agents” by Yadav et al. The article reported the synthesis of potent tetrahydroquinoline/isoquinoline molecules of the last 10 years with their anticancer properties in various cancer cell lines and stated their half-maximal inhibitory concentration (IC50). In addition, we also considered the discussion of molecular docking and structural activity relationship wherever provided to understand the possible mode of activity an target involved and structural features responsible for the better activity, so the reader can directly find detail for designing new anticancer agents. [4]. Finally I would like to thank all authors who contributed to this issue, titled “Recent advances on small molecule medicinal chemistry to treat human diseases”.

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