Amine-linked Covalent Organic Frameworks as a Powerful Platform for Post-Synthetic Modification: Structure Interconversion and Combined Linkage- and Pore-Wall-Modification

<div>Covalent organic frameworks have emerged as a powerful synthetic platform for installing and interconverting dedicated molecular functions on a crystalline polymeric backbone with atomic precision. Here, we present a novel strategy to directly access amine-linked covalent organic frameworks, which serve as a scaffold enabling pore-wall modification and linkage-interconversion by new synthetic methods based on Leuckart-Wallach reduction with formic acid and ammonium formate. Frameworks connected entirely by secondary amine linkages, mixed amine/imine bonds, and partially formylated amine linkages are obtained in a single step from imine-linked frameworks, or directly from corresponding linkers in a one-pot crystallisation-reduction approach. The new, 2D amine-linked covalent organic frameworks, rPI-3-COF, rTTI-COF, and rPy1P-COF, are obtained with high crystallinity and large surface areas. Secondary amines, installed as reactive-sites on the pore wall, enable further post-synthetic functionalisation to access tailored covalent organic frameworks, with increased hydrolytic stability, as potential heterogeneous catalysts.</div>

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Facile Synthesis of COF-Supported Reduced Pd-Based Catalyst for One-Pot Reductive Amination of Aldehydes

Catalysts ◽

10.3390/catal11020287 ◽

2021 ◽

Vol 11 (2) ◽

pp. 287

Author(s):

Jianguo Liu ◽

Mingyue Zhang ◽

Longlong Ma

Keyword(s):

Heterogeneous Catalysts ◽

Reductive Amination ◽

Secondary Amines ◽

Metallic State ◽

One Pot ◽

Effective Synthesis ◽

Pharmaceutical Industries ◽

The One ◽

Heterocyclic Aldehydes ◽

Supported Pd

Dibenzylamine motifs are an important class of crucial organic compounds and are widely used in fine chemical and pharmaceutical industries. The development of the efficient, economical, and environmentally friendly synthesis of amines using transition metal-based heterogeneous catalysts remains both desirable and challenging. Herein, we prepared the covalent organic framework (COF)-supported heterogeneous reduced COF-supported Pd-based catalyst and used it for the one-pot reductive amination of aldehydes. There are both Pd metallic state and oxidated Pdσ+ in the catalysts. Furthermore, in the presence of the reduced COF-supported Pd-based catalyst, many aromatic, aliphatic, and heterocyclic aldehydes with various functional groups substituted were converted to their corresponding amines products in good to excellent selectivity (up to 91%) under mild reaction conditions (70 °C, 2 h, NH3, 20 bar H2). This work expands the covalent organic frameworks for the material family and its support catalyst, opening up new catalytic applications in the economical, practical, and effective synthesis of secondary amines.

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Supported bimetallic nano-alloys as highly active catalysts for the one-pot tandem synthesis of imines and secondary amines from nitrobenzene and alcohols

Catalysis Science & Technology ◽

10.1039/c6cy00425c ◽

2016 ◽

Vol 6 (14) ◽

pp. 5473-5482 ◽

Cited By ~ 25

Author(s):

Meenakshisundaram Sankar ◽

Qian He ◽

Simon Dawson ◽

Ewa Nowicka ◽

Li Lu ◽

...

Keyword(s):

Heterogeneous Catalysts ◽

Secondary Amines ◽

One Pot ◽

Benzylic Alcohols ◽

One Pot Synthesis ◽

Highly Active ◽

The One ◽

Tandem Synthesis

All-in-one: supported nanoalloys as efficient heterogeneous catalysts for the one-pot synthesis of imines and secondary amines directly from nitrobenzene and benzylic alcohols using a hydrogen auto transfer strategy.

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Advances in Green Catalysis for the Synthesis of Medicinally Relevant N-Heterocycles

Catalysts ◽

10.3390/catal11091108 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1108

Author(s):

A. Sofia Santos ◽

Daniel Raydan ◽

José C. Cunha ◽

Nuno Viduedo ◽

Artur M. S. Silva ◽

...

Keyword(s):

Heterocyclic Compounds ◽

Heterogeneous Catalysts ◽

Catalytic Synthesis ◽

Biologically Active ◽

Synthetic Methods ◽

One Pot ◽

Metal Catalyzed ◽

The Individual ◽

Green Catalysis ◽

Synthetic Approaches

N-heterocycles, both saturated and unsaturated, are ubiquitous biologically active molecules that are extremely appealing scaffolds in drug discovery programs. Although classical synthetic methods have been developed to access many relevant N-heterocyclic scaffolds, representing well-established and reliable routes, some do not meet the needs of sustainability. In this context, several advances have been made towards the sustainable synthesis of N-heterocycles. This review focuses on the most recent examples from the last five years of catalytic synthesis of several heterocyclic compounds of medicinal relevance. Thus, the synthesis of isoindoloquinazolines, quinazolines and azaindoles, among others, are covered. The synthetic methods selected include the use of homogeneous and heterogeneous catalysts and the use of alternative and sustainable methods such as, for example, metal-catalyzed acceptorless coupling and one-pot reactions. The green aspects of the individual synthetic approaches are highlighted, and the scope of each methodology is described.

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One-pot amination of aldehydes and ketones over heterogeneous catalysts for production of secondary amines

Catalysis Reviews ◽

10.1080/01614940.2021.1942689 ◽

2021 ◽

pp. 1-68

Author(s):

Päivi Mäki-Arvela ◽

Irina L. Simakova ◽

Dmitry Yu. Murzin

Keyword(s):

Heterogeneous Catalysts ◽

Secondary Amines ◽

One Pot ◽

Aldehydes And Ketones

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Selenoxide Elimination Triggers Enamine Hydrolysis to Primary and Secondary Amines: A Combined Experimental and Theoretical Investigation

Molecules ◽

10.3390/molecules26092770 ◽

2021 ◽

Vol 26 (9) ◽

pp. 2770

Author(s):

Giovanni Ribaudo ◽

Marco Bortoli ◽

Erika Oselladore ◽

Alberto Ongaro ◽

Alessandra Gianoncelli ◽

...

Keyword(s):

Mass Spectrometry ◽

Density Functional ◽

Underlying Mechanism ◽

Model Reaction ◽

Bioactive Molecules ◽

Secondary Amines ◽

One Pot ◽

Functional Theory ◽

Primary And Secondary Amines ◽

Novel Strategy

We discuss a novel selenium-based reaction mechanism consisting in a selenoxide elimination-triggered enamine hydrolysis. This one-pot model reaction was studied for a set of substrates. Under oxidative conditions, we observed and characterized the formation of primary and secondary amines as elimination products of such compounds, paving the way for a novel strategy to selectively release bioactive molecules. The underlying mechanism was investigated using NMR, mass spectrometry and density functional theory (DFT).

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Simultaneous Adsorption and Reduction of Cr(VI) to Cr(III) in Aqueous Solution Using Nitrogen-Rich Aminal Linked Porous Organic Polymers

Sustainability ◽

10.3390/su13020923 ◽

2021 ◽

Vol 13 (2) ◽

pp. 923

Author(s):

Muhammad A. Sabri ◽

Ziad Sara ◽

Mohammad H. Al-Sayah ◽

Taleb H. Ibrahim ◽

Mustafa I. Khamis ◽

...

Keyword(s):

Active Sites ◽

Condensation Reaction ◽

Significant Loss ◽

Single Step ◽

High Porosity ◽

Organic Polymers ◽

Porous Organic Polymers ◽

One Pot ◽

Surface Areas ◽

Redox Active

Two novel nitrogen-rich aminal linked porous organic polymers, NRAPOP-O and NRAPOP-S, have been prepared using a single step-one pot Schiff-base condensation reaction of 9,10-bis-(4,6-diamino-S-triazin-2-yl)benzene and 2-furaldehyde or 2-thiophenecarboxaldehyde, respectively. The two polymers show excellent thermal and physiochemical stabilities and possess high porosity with Brunauer–Emmett–Teller (BET) surface areas of 692 and 803 m2 g−1 for NRAPOP-O and NRAPOP-S, respectively. Because of such porosity, attractive chemical and physical properties, and the availability of redox-active sites and physical environment, the NRAPOPs were able to effectively remove Cr(VI) from solution, reduce it to Cr(III), and simultaneously release it into the solution. The efficiency of the adsorption process was assessed under various influencing factors such as pH, contact time, polymer dosage, and initial concentration of Cr(VI). At the optimum conditions, 100% removal of Cr(VI) was achieved, with simultaneous reduction and release of Cr(III) by NRAPOP-O with 80% efficiency. Moreover, the polymers can be easily regenerated by the addition of reducing agents such as hydrazine without significant loss in the detoxication of Cr(VI).

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Microwave-accelerated Carbon-carbon and Carbon-heteroatom Bond Formation via Multi-component Reactions: A Brief Overview

Current Microwave Chemistry ◽

10.2174/2213346107666200218124147 ◽

2020 ◽

Vol 7 (1) ◽

pp. 23-39 ◽

Cited By ~ 2

Author(s):

Kantharaju Kamanna ◽

Santosh Y. Khatavi

Keyword(s):

Organic Synthesis ◽

Bond Formation ◽

Cycloaddition Reaction ◽

Nanoparticle Synthesis ◽

Single Step ◽

Bioactive Molecules ◽

One Pot ◽

Bond Forming ◽

Material Interest ◽

Carbon Carbon Bond

Multi-Component Reactions (MCRs) have emerged as an excellent tool in organic chemistry for the synthesis of various bioactive molecules. Among these, one-pot MCRs are included, in which organic reactants react with domino in a single-step process. This has become an alternative platform for the organic chemists, because of their simple operation, less purification methods, no side product and faster reaction time. One of the important applications of the MCRs can be drawn in carbon- carbon (C-C) and carbon-heteroatom (C-X; X = N, O, S) bond formation, which is extensively used by the organic chemists to generate bioactive or useful material synthesis. Some of the key carbon- carbon bond forming reactions are Grignard, Wittig, Enolate alkylation, Aldol, Claisen condensation, Michael and more organic reactions. Alternatively, carbon-heteroatoms containing C-N, C-O, and C-S bond are also found more important and present in various heterocyclic compounds, which are of biological, pharmaceutical, and material interest. Thus, there is a clear scope for the discovery and development of cleaner reaction, faster reaction rate, atom economy and efficient one-pot synthesis for sustainable production of diverse and structurally complex organic molecules. Reactions that required hours to run completely in a conventional method can now be carried out within minutes. Thus, the application of microwave (MW) radiation in organic synthesis has become more promising considerable amount in resource-friendly and eco-friendly processes. The technique of microwaveassisted organic synthesis (MAOS) has successfully been employed in various material syntheses, such as transition metal-catalyzed cross-coupling, dipolar cycloaddition reaction, biomolecule synthesis, polymer formation, and the nanoparticle synthesis. The application of the microwave-technique in carbon-carbon and carbon-heteroatom bond formations via MCRs with major reported literature examples are discussed in this review.

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Six-Sided Heptaporphyrin Array: Towards a Nano-Sized Cube

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20040996 ◽

2004 ◽

Vol 69 (5) ◽

pp. 996-1008 ◽

Cited By ~ 13

Author(s):

Steven J. Langford ◽

Clint P. Woodward

Keyword(s):

Single Step ◽

One Pot ◽

H Nmr ◽

The Core ◽

Nmr Techniques ◽

Axial Vertex

A strategy in preparing a family of hexameric porphyrin cubes based on the interplay of Sn(IV)-O and Ru(II)-N interactions is described. In this first iteration, we have prepared the heptamer [SnIV(TPyP)·(4)2][Ru(CO)(TPP)]6 (4 = (E)-(3-(4-pyridyl)acrylate)) constituting a 5,10,15,20-tetra(4-pyridyl)porphyrin (TPyP) core and 5,10,15,20-tetraphenylporphyrin (TPP) faces and compared its formation by stepwise and "one-pot" strategies where up to nine components are assembled in a single step in a regiospecific manner. In one example, the heptamer is formed around the template [SnIV(TPyP)·(4)2] bearing pyridine groups in which the nitrogens radiate octahedrally along each vertex. The ability to modulate the axial vertex through choice of pyridine is also demonstrated. 1H NMR measurements on [SnIV(TPyP)·(4)2][Ru(CO)(TPP)]6 indicate that the protons on the core template are extremely shielded as a result of the anisotropy of the peripheral porphyrin units. Various NMR techniques, including NOESY experiments, have been used to characterise the heptamer in solution.

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One-Pot Hydrothermal Synthesis of Victoria Green (Ca3Cr2Si3O12) Nanoparticles in Alkaline Fluids and Its Colour Hue Characterisation

Nanomaterials ◽

10.3390/nano11020521 ◽

2021 ◽

Vol 11 (2) ◽

pp. 521

Author(s):

Juan Carlos Rendón-Angeles ◽

Zully Matamoros-Veloza ◽

Jose Luis Rodríguez-Galicia ◽

Gimyeong Seong ◽

Kazumichi Yanagisawa ◽

...

Keyword(s):

Near Infrared ◽

Single Step ◽

Spectral Space ◽

Infrared Reflectance ◽

Hydrothermal Preparation ◽

Near Infrared Reflectance ◽

One Pot ◽

Factors Affecting ◽

B Values ◽

Alkaline Conditions

One-pot hydrothermal preparation of Ca3Cr2Si3O12 uvarovite nanoparticles under alkaline conditions was investigated for the first time. The experimental parameters selected for the study considered the concentration of the KOH solvent solution (0.01 to 5.0 M), the agitation of the autoclave (50 rpm), and the nominal content of Si4+ (2.2–3.0 mole). Fine uvarovite particles were synthesised at 200 °C after a 3 h interval in a highly concentrated 5.0 M KOH solution. The crystallisation of single-phase Ca3Cr2Si3O12 particles proceeded free of by-products via a one-pot process involving a single-step reaction. KOH solutions below 2.5 M and water hindered the crystallisation of the Ca3Cr2Si3O12 particles. The hydrothermal treatments carried out with stirring (50 rpm) and non-stirring triggered the crystallisation of irregular anhedral particles with average sizes of 8.05 and 12.25 nm, respectively. These particles spontaneously assembled into popcorn-shaped agglomerates with sizes varying from 66 to 156 nm. All the powders prepared by the present method exhibited CIE-L*a*b* values that correspond to the Victoria green colour spectral space and have a high near infrared reflectance property. The particle size and structural crystallinity are factors affecting the Victoria pigment optical properties, such as CIE-L*a*b* values, green tonality, and near-infrared reflectance.

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