scholarly journals Direct C-H-Sulfonylation of 6-Membered Nitrogen-Heteroaromatics

2021 ◽  
Author(s):  
Marius Friedrich ◽  
Lisa Schulz ◽  
Kamil Hofman ◽  
Rene Zangl ◽  
Nina Morgner ◽  
...  
Keyword(s):  
Building Blocks ◽  
Direct Access ◽  
High Demand ◽  
One Pot ◽  
Organometallic Reagents ◽  
Modular Synthesis ◽  
Novel Approach ◽  
Direct Incorporation ◽  
Reliable Methods ◽  
Complex Drug

Heterocyclic sulfones and sulfonamides represent important structural motives in medicinal chemistry and drug development. Therefore, efficient and reliable methods for their construction from simple building blocks are in high demand. Herein we report a novel approach for the direct C-H-sulfonylation of N heteroaromatics via N-activation with triflic anhydride (Tf2O), base-mediated addition of a sulfinate salt and subsequent rearomatization through trifluoromethanesulfinate elimination. This operationally simple one-pot protocol enables direct access to various sulfonylated 6-ring N-heterocycles. It is applicable to the late-stage functionalization of complex, drug-like molecules. The direct incorporation of sulfur dioxide with organometallic reagents as well as the utilization of a rongalite-based sulfonylation reagent provide opportunities for a highly modular synthesis of N-heterocyclic sulfones and sulfonamides from three different building blocks.

Lewis Base Promoted Delayed Copper Catalysis: Borylative α-C-H Allylation of Alicyclic Amines

2020 ◽  
Author(s):  
Borja Pérez-Saavedra ◽  
Álvaro Velasco-Rubio ◽  
Carlos Saá ◽  
Martín Fañanás-Mastral
Keyword(s):  
Functional Group ◽  
Catalytic Amount ◽  
Building Blocks ◽  
Lewis Base ◽  
Secondary Amines ◽  
Copper Catalysis ◽  
Successful Implementation ◽  
Organometallic Reagents ◽  
Novel Approach

Functionalized alicyclic amines are important building blocks for the synthesis of bioactive natural compounds and drugs. Existing methods of functionalization are typically limited to the synthesis of protected amines or the use of highly basic organometallic reagents that can compromise functional group tolerance. Here, we report a novel approach for the synthesis of α-functionalized cyclic secondary amines. The method employs a copper/bisphosphine catalyst which promotes a regio-, stereo- and chemoselective coupling between allenes, bis(pinacolato)diboron and <i>O</i>-benzoyl hydroxylamines that involves trapping of an in-situ generated alicyclic imine by a catalytic boron-substituted allylcopper intermediate. Successful implementation requires that competing reaction between the allylcopper complex and hydroxylamine is suppressed while imine is formed. This challenge was met by using a catalytic amount of Lewis base additive which delays the catalyst function towards C-N coupling thus enabling selective C-C coupling.

Lewis Base Promoted Delayed Copper Catalysis: Borylative α-C-H Allylation of Alicyclic Amines

2020 ◽  
Author(s):  
Borja Pérez-Saavedra ◽  
Álvaro Velasco-Rubio ◽  
Carlos Saá ◽  
Martín Fañanás-Mastral
Keyword(s):  
Functional Group ◽  
Catalytic Amount ◽  
Building Blocks ◽  
Lewis Base ◽  
Secondary Amines ◽  
Copper Catalysis ◽  
Successful Implementation ◽  
Organometallic Reagents ◽  
Novel Approach

Functionalized alicyclic amines are important building blocks for the synthesis of bioactive natural compounds and drugs. Existing methods of functionalization are typically limited to the synthesis of protected amines or the use of highly basic organometallic reagents that can compromise functional group tolerance. Here, we report a novel approach for the synthesis of α-functionalized cyclic secondary amines. The method employs a copper/bisphosphine catalyst which promotes a regio-, stereo- and chemoselective coupling between allenes, bis(pinacolato)diboron and <i>O</i>-benzoyl hydroxylamines that involves trapping of an in-situ generated alicyclic imine by a catalytic boron-substituted allylcopper intermediate. Successful implementation requires that competing reaction between the allylcopper complex and hydroxylamine is suppressed while imine is formed. This challenge was met by using a catalytic amount of Lewis base additive which delays the catalyst function towards C-N coupling thus enabling selective C-C coupling.

scholarly journals Direct Access to Highly Enantioenriched α-Branched Acrylonitriles through a one-pot Sequential Asymmetric Michael addition/retro-Dieckmann/retro-Michael Fragmentation Cascade

2020 ◽  
Author(s):  
Nicolas Duchemin ◽  
Martin Cattoen ◽  
Oscar Gayraud ◽  
Silvia Anselmi ◽  
Bilal Siddiq ◽  
...  
Keyword(s):  
Michael Addition ◽  
Building Blocks ◽  
Enantioselective Synthesis ◽  
Direct Access ◽  
One Pot ◽  
Asymmetric Michael Addition ◽  
Wide Range

A highly enantioselective synthesis of a-branched acrylonitriles is reported featuring a one-pot sequential asymmetric Michael addition/retro-Dieckmann/retro-Michael fragmentation cascade. The method, which relies on a solid, bench-stable and commercially available acrylonitrile surrogate, is practical, scalable, highly versatile, and provides a direct access to a wide range of enantioenriched nitrile-containing building blocks. Most importantly, the method offers a new tool to incorporate an acrylonitrile moiety in an asymmetric fashion.<br>

Synthesis of Nitrile-Bearing Quaternary Centers via an Equilibrium-Driven Transnitrilation and Anion-Relay Strategy

2019 ◽  
Author(s):  
Sebastien Alazet ◽  
Michael West ◽  
Purvish Patel ◽  
Sophie Rousseaux
Keyword(s):  
Building Blocks ◽  
One Pot ◽  
Quaternary Centers ◽  
Synthetic Intermediates

The efficient preparation of nitrile-containing building blocks is of interest due to their utility as synthetic intermediates and their prevalence in pharmaceuticals. As a result, significant efforts have been made to develop methods to access these motifs which rely on safer and non-toxic sources of CN. Herein, we report that 2-methyl-2-phenylpropanenitrile is an efficient, non-toxic, electrophilic CN source for the synthesis of nitrile-bearing quaternary centers via a thermodynamic transnitrilation and anion-relay strategy. This one-pot process leads to nitrile products resulting from the gem-difunctionalization of alkyl lithium reagents.<br>

scholarly journals A novel approach to the computation of one-loop three- and four-point functions: I. The real mass case

2019 ◽  
Vol 2019 (11) ◽  
Author(s):  
J Ph Guillet ◽  
E Pilon ◽  
Y Shimizu ◽  
M S Zidi
Keyword(s):  
Building Blocks ◽  
The Real ◽  
Alternative Method ◽  
Novel Approach ◽  
Reduction Methods ◽  
Real Mass ◽  
Novel Method ◽  
Algebraic Reduction ◽  
The One ◽  
Mass Case

Abstract This article is the first of a series of three presenting an alternative method of computing the one-loop scalar integrals. This novel method enjoys a couple of interesting features as compared with the method closely following ’t Hooft and Veltman adopted previously. It directly proceeds in terms of the quantities driving algebraic reduction methods. It applies to the three-point functions and, in a similar way, to the four-point functions. It also extends to complex masses without much complication. Lastly, it extends to kinematics more general than that of the physical, e.g., collider processes relevant at one loop. This last feature may be useful when considering the application of this method beyond one loop using generalized one-loop integrals as building blocks.

Synthesis of Pyrrolo[1,2-a][1,6]- and [1,8]naphthyridines by Alkyne-Carbonyl Metathesis

Synthesis ◽  
2020 ◽  
Author(s):  
Peter Ehlers ◽  
Peter Langer ◽  
Marian Blanco Ponce ◽  
Silvio Parpart ◽  
Alexander Villinger ◽  
...  
Keyword(s):  
Heterocyclic Compounds ◽  
Metathesis Reaction ◽  
Synthetic Methodology ◽  
Facile Synthesis ◽  
Reaction Conditions ◽  
One Pot ◽  
Metal Free ◽  
Modular Synthesis

AbstractA concise and modular synthesis of pyrrolo[1,2-a][1,6]- and [1,8]naphthyridines by a one-pot two-step reaction consisting of electrophilic acylation followed by an alkyne-carbonyl-metathesis reaction as the final cyclization step is reported. This developed synthetic methodology allows the facile synthesis of these heterocyclic core structures in mainly high overall yields under metal-free conditions. Reaction conditions are carefully optimized and display a novel supplement to access these tricyclic heterocyclic compounds.

scholarly journals Synthesis of 4-Substituted-1,2-Dihydroquinolines by Means of Gold-Catalyzed Intramolecular Hydroarylation Reaction of N-Ethoxycarbonyl-N-Propargylanilines

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3366
Author(s):  
Antonio Arcadi ◽  
Andrea Calcaterra ◽  
Giancarlo Fabrizi ◽  
Andrea Fochetti ◽  
Antonella Goggiamani ◽  
...  
Keyword(s):  
Building Blocks ◽  
Fine Tuning ◽  
Para Position ◽  
Cyclization Product ◽  
Synthetic Route ◽  
Substituted Anilines ◽  
Novel Approach ◽  
High Yields

An alternative Au(I)-catalyzed synthetic route to functionalized 1,2-dihydroquinolines is reported. This novel approach is based on the use of N-ethoxycarbonyl protected-N-propargylanilines as building blocks that rapidly undergo the IMHA reaction affording the 6-endo cyclization product in good to high yields. In the presence of N-ethoxycarbonyl-N-propargyl-meta-substituted anilines, the regiodivergent cyclization at the ortho-/para-position is achieved by the means of catalyst fine tuning.

scholarly journals Compiling Life-Oriented Moral Education Textbooks for Elementary Schools in China: The Mimetic Approach in Morality and Law

2021 ◽  
pp. 209653112098296
Author(s):  
Yan Tang
Keyword(s):  
Elementary Schools ◽  
Moral Education ◽  
Life Events ◽  
Theoretical Perspective ◽  
Building Blocks ◽  
Learning Activities ◽  
Design Approach ◽  
New Approach ◽  
Novel Approach

Purpose: This study explores a novel approach to compiling life-oriented moral textbooks for elementary schools in China, specifically focusing on Morality and Law. Design/Approach/Methods: Adopting Aristotle’s Poetics as its theoretical perspective, this study illustrates and analyzes the mimetic approach used in compiling the life-oriented moral education textbook, Morality and Law. Findings: The mimetic approach involves imitating children's real activities, thoughts, and feelings in textbooks. The mimetic approach to compiling life-oriented moral textbooks comprises three strategies: constructing children's life events as building blocks for textbook compilation, designing an intricate textual device exposing the wholeness of children's life actions, and designing inward learning activities leading to children's inner worlds. Originality/Value: From the perspective of Aristotle's Poetics, the approach to compilation in Morality and Law can be defined as mimetic. And the compilation activity in the life-oriented moral education textbook also can be described as a processes of mimesis. So this article presents a new approach to compile moral education textbooks, and  an innovative way to understand the nature of one compiling activity.

scholarly journals 2-Aryl-6-Polyfluoroalkyl-4-Pyrones as Promising RF-Building-Blocks: Synthesis and Application for Construction of Fluorinated Azaheterocycles

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4415
Author(s):  
Sergey A. Usachev ◽  
Diana I. Nigamatova ◽  
Daria K. Mysik ◽  
Nikita A. Naumov ◽  
Dmitrii L. Obydennov ◽  
...  
Keyword(s):  
Direct Synthesis ◽  
Building Blocks ◽  
Oxidative Cyclization ◽  
One Pot ◽  
Synthetic Application ◽  
General Method

A convenient and general method for the direct synthesis of 2-aryl-6-(trifluoromethyl)-4-pyrones and 2-aryl-5-bromo-6-(trifluoromethyl)-4-pyrones has been developed on the basis of one-pot oxidative cyclization of (E)-6-aryl-1,1,1-trifluorohex-5-ene-2,4-diones via a bromination/dehydrobromination approach. This strategy was also applied for the preparation of 2-phenyl-6-polyfluoroalkyl-4-pyrones and their 5-bromo derivatives. Conditions of chemoselective enediones bromination were found and the key intermediates of the cyclization of bromo-derivatives to 4-pyrones were characterized. Synthetic application of the prepared 4-pyrones has been demonstrated for the construction of biologically important CF3-bearing azaheterocycles, such as pyrazoles, pyridones, and triazoles.

scholarly journals Collision Avoidance on Unmanned Aerial Vehicles Using Neural Network Pipelines and Flow Clustering Techniques

2021 ◽  
Vol 13 (13) ◽  
pp. 2643
Author(s):  
Dário Pedro ◽  
João P. Matos-Carvalho ◽  
José M. Fonseca ◽  
André Mora
Keyword(s):  
Collision Avoidance ◽  
Autonomous Vehicles ◽  
High Demand ◽  
Novel Approach ◽  
Vision Sensors ◽  
Learning Techniques ◽  
Stationary Objects ◽  
Computationally Intensive ◽  
Unmanned Autonomous Vehicles ◽  
Positive Results

Unmanned Autonomous Vehicles (UAV), while not a recent invention, have recently acquired a prominent position in many industries, and they are increasingly used not only by avid customers, but also in high-demand technical use-cases, and will have a significant societal effect in the coming years. However, the use of UAVs is fraught with significant safety threats, such as collisions with dynamic obstacles (other UAVs, birds, or randomly thrown objects). This research focuses on a safety problem that is often overlooked due to a lack of technology and solutions to address it: collisions with non-stationary objects. A novel approach is described that employs deep learning techniques to solve the computationally intensive problem of real-time collision avoidance with dynamic objects using off-the-shelf commercial vision sensors. The suggested approach’s viability was corroborated by multiple experiments, firstly in simulation, and afterward in a concrete real-world case, that consists of dodging a thrown ball. A novel video dataset was created and made available for this purpose, and transfer learning was also tested, with positive results.

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