scholarly journals Direct catalytic arylation of heteroarenes with meso-bromophenyl-substituted porphyrins

2017 ◽  
Vol 13 ◽  
pp. 1524-1532 ◽  
Author(s):  
Alexei Nikolaevich Kiselev ◽  
Olga Konstantinovna Grigorova ◽  
Alexei Dmitrievich Averin ◽  
Sergei Aleksandrovich Syrbu ◽  
Oskar Iosifovich Koifman ◽  
...  
Keyword(s):  
Catalytic System ◽  
Catalytic Systems ◽  
The Third ◽  
Derivatives Of

The arylation of mono-, di- and tetra-meso-bromophenyl-substituted porphyrins with the heteroarenes containing “acidic” C–H bonds, such as benzoxazole, benzothiazole and N-methylimidazole was studied in the presence of three alternative catalytic systems: Pd(dba)2/DavePhos/Cs2CO3, Pd(PPh3)4/PivOH/K2CO3 and Pd(OAc)2/Cu(OAc)2/PPh3/K2CO3. The first catalytic system was found to be successful in the reaction with benzoxazole, the second one was less efficient for our purpose, while the third system proved to be most versatile and afforded corresponding mono-, di-, tri- and even tetraarylated derivatives of porphyrins.

scholarly journals Mini-Review on the Synthesis of Furfural and Levulinic Acid from Lignocellulosic Biomass

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1234
Author(s):  
Zhiwei Jiang ◽  
Di Hu ◽  
Zhiyue Zhao ◽  
Zixiao Yi ◽  
Zuo Chen ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Lignocellulosic Biomass ◽  
Catalytic System ◽  
Levulinic Acid ◽  
Value Added ◽  
Environmental Issues ◽  
Alternative Route ◽  
Catalytic Systems ◽  
Renewable Biomass ◽  
Platform Chemicals

Efficient conversion of renewable biomass into value-added chemicals and biofuels is regarded as an alternative route to reduce our high dependence on fossil resources and the associated environmental issues. In this context, biomass-based furfural and levulinic acid (LA) platform chemicals are frequently utilized to synthesize various valuable chemicals and biofuels. In this review, the reaction mechanism and catalytic system developed for the generation of furfural and levulinic acid are summarized and compared. Special efforts are focused on the different catalytic systems for the synthesis of furfural and levulinic acid. The corresponding challenges and outlooks are also observed.

scholarly journals Third derivatives of the integrable part of an asteroid Hamiltonian

2007 ◽  
pp. 53-60 ◽  
Author(s):  
R. Pavlovic
Keyword(s):  
Third Order ◽  
Geometrical Condition ◽  
The Third ◽  
Derivatives Of ◽  
Quasi Convexity ◽  
Explicit Expressions

To apply the theorem of Nekhoroshev (1977) to asteroids, one first has to check whether a necessary geometrical condition is fulfilled: either convexity, or quasi-convexity, or only a 3-jet non-degeneracy. This requires computation of the derivatives of the integrable part of the corresponding Hamiltonian up to the third order over actions and a thorough analysis of their properties. In this paper we describe in detail the procedure of derivation and we give explicit expressions for the obtained derivatives. .

Synthesis of 2-aminothiazoles from methylcarbonyl compounds using a Fe3O4 nanoparticle-N-halo reagent catalytic system

RSC Advances ◽  
2016 ◽  
Vol 6 (69) ◽  
pp. 64749-64755 ◽  
Author(s):  
Masoud Sadeghi ◽  
Javad Safari ◽  
Zohre Zarnegar
Keyword(s):  
Catalytic System ◽  
Fe3o4 Nanoparticle ◽  
Catalytic Systems ◽  
System P

An efficient protocol is developed for the synthesis of 2-aminothiazoles from unfunctionalized methylcarbonyl compounds using Fe3O4 nanoparticle-N-halo reagent catalytic systems.

scholarly journals Ruthenium-Based Catalytic Systems Incorporating a Labile Cyclooctadiene Ligand with N-Heterocyclic Carbene Precursors for the Atom-Economic Alcohol Amidation Using Amines

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2413 ◽  
Author(s):  
Cheng Chen ◽  
Yang Miao ◽  
Kimmy De Winter ◽  
Hua-Jing Wang ◽  
Patrick Demeyere ◽  
...  
Keyword(s):  
Catalytic System ◽  
High Resolution Mass Spectrometry ◽  
Amide Bond ◽  
Catalyst Loading ◽  
Catalytic Systems ◽  
Amide Bond Formation ◽  
Highly Active ◽  
Metal Catalyzed ◽  
Ru Species

Transition-metal-catalyzed amide-bond formation from alcohols and amines is an atom-economic and eco-friendly route. Herein, we identified a highly active in situ N-heterocyclic carbene (NHC)/ruthenium (Ru) catalytic system for this amide synthesis. Various substrates, including sterically hindered ones, could be directly transformed into the corresponding amides with the catalyst loading as low as 0.25 mol.%. In this system, we replaced the p-cymene ligand of the Ru source with a relatively labile cyclooctadiene (cod) ligand so as to more efficiently obtain the corresponding poly-carbene Ru species. Expectedly, the weaker cod ligand could be more easily substituted with multiple mono-NHC ligands. Further high-resolution mass spectrometry (HRMS) analyses revealed that two tetra-carbene complexes were probably generated from the in situ catalytic system.

Algorithm for implementation of the «third decision scheme» of increasing the efficiency of search and synchronization of difficult broadband noise like signals

2021 ◽  
Author(s):  
I.I. Snytkin ◽  
T.I. Snytkin
Keyword(s):  
Central Element ◽  
Broadband Noise ◽  
Telecommunication Networks ◽  
Complex Signals ◽  
The Third ◽  
Recurrent Sequences ◽  
Decision Scheme ◽  
Code Structure ◽  
Wideband Signals ◽  
Derivatives Of

The construction of telecommunication networks with a guaranteed level of quality of service involves assessing and ensuring the security of both the networks themselves and information flows from unauthorized access and various kinds of interference, in particular at the 1st (physical) level of the network. In this regard, research in the field of creating recurrent code sequences with improved systemic, correlation, secretive, imitation-resistant properties is constantly relevant. In particular, research in the development and application of derivative nonlinear recurrent sequences, as a central element in the developed theory of the «third decision scheme». Goal of the work is to develop an algorithm for increasing the efficiency of search and synchronization of broadband signals in the form of double derivatives of nonlinear recurrent sequences, which directly uses the features of their code structure, the properties of determinism of their auto- and cross-correlation functions. The results of the research and development of the efficiency of the algorithm for accelerated search and synchronization of broadband complex signals in the form of phase-shift keyed derivatives of nonlinear recurrent sequences, which implements the principles of the «third decision schema» The developed algorithm, based on the use of double derivatives of nonlinear recurrent sequences as wideband signals, can be applied in the construction of promising packet radio networks.

Efficient and phosphine-free bidentate N-heterocyclic carbene/ruthenium catalytic systems for the dehydrogenative amidation of alcohols and amines

2019 ◽  
Vol 6 (5) ◽  
pp. 563-570 ◽  
Author(s):  
Xuan-Jun Wu ◽  
Hua-Jing Wang ◽  
Zhao-Qi Yang ◽  
Xiao-Sheng Tang ◽  
Ye Yuan ◽  
...  
Keyword(s):  
Catalytic System ◽  
Catalytic Systems ◽  
Amide Synthesis

An efficient and phosphine-free bidentate NHC/Ru catalytic system was discovered for the dehydrogenative amide synthesis from alcohols and amines.

scholarly journals Valorization of Biomass Derived Terpene Compounds by Catalytic Amination

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 365 ◽  
Author(s):  
Irina L. Simakova ◽  
Andrey V. Simakov ◽  
Dmitry Yu. Murzin
Keyword(s):  
Transition Metal ◽  
Nucleophilic Substitution ◽  
Transition Metal Complexes ◽  
Production Costs ◽  
Solid Materials ◽  
Catalytic Systems ◽  
Solid Catalysts ◽  
Catalytic Amination ◽  
Derivatives Of

This review fills an apparent gap existing in the literature by providing an overview of the readily available terpenes and existing catalytic protocols for preparation of terpene-derived amines. To address the role of solid catalysts in amination of terpenes the same reactions with homogeneous counterparts are also discussed. Such catalysts can be considered as a benchmark, which solid catalysts should match. Although catalytic systems based on transition metal complexes have been developed for synthesis of amines to a larger extent, there is an apparent need to reduce the production costs. Subsequently, homogenous systems based on cheaper metals operating by nucleophilic substitution (e.g., Ni, Co, Cu, Fe) with a possibility of easy recycling, as well as metal nanoparticles (e.g., Pd, Au) supported on amphoteric oxides should be developed. These catalysts will allow synthesis of amine derivatives of terpenes which have a broad range of applications as specialty chemicals (e.g., pesticides, surfactants, etc.) and pharmaceuticals. The review will be useful in selection and design of appropriate solid materials with tailored properties as efficient catalysts for amination of terpenes.

scholarly journals Volume derivatives of the Grüneisen parameter in the limit of infinite pressure

2019 ◽  
Vol 97 (1) ◽  
pp. 114-116 ◽  
Author(s):  
A. Dwivedi
Keyword(s):  
Boundary Condition ◽  
Fourth Order ◽  
Fundamental Theorem ◽  
High Pressures ◽  
Grüneisen Parameter ◽  
Third Order ◽  
Gruneisen Parameter ◽  
The Third ◽  
Properties Of Materials ◽  
Derivatives Of

Expressions have been obtained for the volume derivatives of the Grüneisen parameter, which is directly related to the thermal and elastic properties of materials at high temperatures and high pressures. The higher order Grüneisen parameters are expressed in terms of the volume derivatives, and evaluated in the limit of infinite pressure. The results, that at extreme compression the third-order Grüneisen parameter remains finite and the fourth-order Grüneisen parameter tends to zero, have been used to derive a fundamental theorem according to which the volume derivatives of the Grüneisen parameter of different orders, all become zero in the limit of infinite pressure. However, the ratios of these derivatives remain finite at extreme compression. The formula due to Al’tshuler and used by Dorogokupets and Oganov for interpolating the Grüneisen parameter at intermediate compressions has been found to satisfy the boundary condition at infinite pressure obtained in the present study.

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