Amination Of Aldehydes Research Articles

A novel bio-based epoxy resin curing agent of gluconic aldehyde amine for the preparation of epoxy resin film

To resolve the shortage of fossil resources, gluconic aldehyde amine (GAA) was prepared from glucose via Mannich reaction, and then was used to cure E901 epoxy resin to prepare glucose-based epoxy resin film (GAAF). Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy indicated the successful synthesis of GAA. With the increase of Mannich reaction temperature, the tensile strength and elongation at break of GAAF firstly increased and then decreased, as well as the thermal stability increased. The GAAF-60 sample exhibited maximum tensile strength of 47.5 MPa, which were higher than that prepared by petroleum-based phenolic amine and lignin-based phenolic amine, respectively. The synthesis of GAA presented a novel bio-based epoxy resin curing agent for the preparation of epoxy resin film.

Hydrogen Bond‐Assisted Macrocyclic Synthesis: An Extended Application For 4‐Hydroxybenzylamine Derivatives

AbstractThis work involved synthesizing three N‐benzyl‐4‐hydroxybenzylamines using indirect reductive amination of aromatic aldehydes and 4‐hydroxybenzylamine. Such benzylamines’ reaction with formaldehyde produced tricyclic azacyclophanes formed by two benzylamine units joined by methylene bridges. Computational calculations established that macrocyclization was promoted by template formation stabilized by hydrogen bonds and π‐stacking.

Preparation of hydrogel from the hydroalcoholic root extract of Premna integrifolia L. and its mediated green synthesis of silver nanoparticles for wound healing efficacy

The current investigation concentrated on the fabrication of silver nanoparticles through the root of Premna integrifolia L. The antibacterial and wound healing effects of their silver nanoparticles-hydrogel and root extract-hydrogel were evaluated. The hydroalcoholic root extract of P. integrifolia was enriched with crocetin, ferulic acid, oleanolic acid, oleic acid, syringic acid, and vanillin. The silver nanoparticles were biosynthesized through secondary metabolite-enriched hydroalcoholic root extract (5 %) when mixed with 1 mM AgNO3 and kept under sunlight for 10 minutes. They showed an optimum surface plasmon resonance (SPR) at 447 nm. The aldehyde, phenol, and primary amine groups of the extract reduce silver cations into nanoparticles. The nanoparticles band gap of 2.06 eV showed their semi-conductance behavior. The nanoparticles were spherical, uniformly distributed, and stable. The nanoparticles had a good roughness profile and 57.55 % elemental silver. The silver nanoparticles-hydrogel (10 %) showed an efficient 11±0.11 nm zone of inhibition of S. aureus in comparison to the root extract-hydrogel (10 %), i.e., 9±0.15 nm. The nanoparticles-hydrogel and the root extract-hydrogel did not show noticeable symptoms of acute dermal toxicity. The nanoparticles-hydrogel (10 %) and the root extract-hydrogel (10 %) healed 99.9 % and 97.3 % of the S. aureus- infected wound, respectively. The nanoparticle-hydrogel efficiently induced re-epithelialization in the dermis of S. aureus-infected wound compared to the extract-hydrogel. The nanoparticle-hydrogel enhanced the rate of wound closure.

Reductive Amination of Aldehyde and Ketone with Ammonia and H2 by an In Situ-Generated Cobalt Catalyst under Mild Conditions.

Herein, we present the simplest approach for the synthesis of primary amines via reductive amination using H2 as a reductant and aqueous ammonia as a nitrogen source, catalyzed by amorphous Co particles. The highly active Co particles were prepared in situ by simply mixing commercially available CoCl2 and NaBH4/NaHBEt3 without any ligand or support. This reaction system features mild conditions (80 °C, 1-10 bar), high selectivity (99%), a wide substrate scope, simple operation, and easy separation of the catalyst. The successful large-scale application of this reaction in the production of primary amines suggests its potential industrial interest.

Assembly-Dissociation-Reconstruction Synthesis of Covalent Organic Framework Membranes with High Continuity for Efficient CO2 Separation.

Covalent organic frameworks (COFs), at the forefront of porous materials, hold tremendous potential in membrane separation; however, achieving high continuity in COF membranes remains crucial for efficient gas separation. Here, we present a unique approach termed assembly-dissociation-reconstruction for fabricating COF membranes tailored for CO2/N2 separation. A parent COF is designed from two-node aldehyde and three-node amine monomers and dissociated to high-aspect-ratio nanosheets. Subsequently, COF nanosheets are orderly reconstructed into a crack-free membrane by surface reaction under water evaporation. The membrane exhibits high crystallinity, open pores and a strong affinity for CO2 adsorption over N2, resulting in CO2 permeance exceeding 1060 GPU and CO2/N2 selectivity surpassing 30.6. The efficacy of this strategy offers valuable guidance for the precise fabrication of gas-separation membranes.

Design of efficient benzimidazole-derived N-heterocyclic carbene Ag(I) catalysts for aldehyde–amine–alkyne coupling

A mild catalytic protocol for aldehyde, amine, and alkyne coupling (A3-coupling) allows for the selective synthesis of propargyl amines using 5,6-dimethylbenzimidazole-derived N-heterocyclic carbene (BNHC) silver(I) catalysts. A series of BNHC Ag(Ⅰ) halide complexes were synthesized and their structures have been elucidated through the use of multinuclear NMR and FT-IR spectroscopy. Furthermore, the pseudo-linear geometry of two different compounds was substantiated by single-crystal X-ray diffraction. Silver-based A3-coupling was achieved for both acyclic and cyclic secondary amines using a diverse set of alkynes to afford propargyl amines with yields of up to 95 %. The present approach is environmentally benign and water is generated as the sole byproduct.

Rapid synthesis of aminal-linked covalent organic frameworks for CO2/CH4 separation.

As an emerging category of crystalline porous materials, covalent organic frameworks (COFs) are primarily synthesized via solvothermal methods. However, achieving rapid synthesis of COFs through this approach poses a significant challenge. To address the issue of slow synthesis, we studied the crystallization process of aminal-linked COFs via the condensation of a cost-effective aldehyde and secondary amine, and successfully expedited the synthesis of COFs within a one-hour duration. Furthermore, gram-scale aminal-linked COFs with abundant ultra-microporous channels demonstrated promising potential for CO2/CH4 separation. This study enables the rapid synthesis of aminal-linked COFs from cheap raw materials, which lays a foundation for their practical applications.

Palladium/Amine Dual-Catalyzed Tsuji-Trost Fluoroallylation of Aldehydes with gem-Difluorinated Cyclopropanes.

We herein disclose the Pd/amine dual-catalyzed ring-opening cross-coupling reaction between gem-difluorinated cyclopropanes (gem-F2CPs) with aldehydes, which enables the diversity-oriented synthesis (DOS) of 2-fluoroallylic aldehydes bearing all-carbon quaternary centers with features of broad scope and excellent functional group tolerance. The synthetic value of this Tsuji-Trost system was further demonstrated by late-stage functionalization of natural product-derived gem-F2CPs and the diverse synthesis of various fluoroallylic aldehyde derivatives, including alcohol, alkyne, alkene, and amine.

Progress on the Synthesis and Applications of Aminals: Scaffolds for Molecular Diversity

AbstractAminals, characterized by a central carbon linking two nitrogen atoms, are versatile building blocks in modern chemistry. This review addresses a literature gap by exploring the synthesis and applications of aminals, with a focus on drug discovery and molecular diversity. Beyond medicinal chemistry, aminals find applications as key components in bioactive compounds and as versatile tools in materials chemistry. The review covers fundamental characteristics, synthetic methodologies, stability, and applications, emphasizing alternative synthetic methods to the well-established aldehyde–amine condensation. This inclusive exploration provides insights into diverse synthetic pathways that expand the versatility of the aminal scaffold.1 Introduction2 The Aminal Group3 Aminal Synthesis3.1 Metal-Free Approaches3.2 Metal-Catalyzed Approaches3.3 Photoredox Methodologies3.4 Via Rearrangements3.5 Via Decarboxylative Coupling4 Aminals as Synthetic Tools5 Synthesis of Aminal-Containing Natural Products6 Aminal-Based Materials7 Conclusions

Synthesis of Amides via the Amination of Aldehydes with Hydroxylamines Promoted by TBAF·3H2O.

A metal-free, mild, and efficient method for the synthesis of amides has been developed from the amination of aldehydes with hydroxylamines promoted by TBAF·3H2O in the presence of KOH. Control experiments showed that the nitrone was the intermediate of this amination. By this method, a series of amides, biologically active compounds bebenil and a COX inhibitor were obtained in moderate to good yields.

Synthesis and Application of Salicylhydrazone Probes with High Selectivity for Rapid Detection of Cu2.

Using the aldehyde amine condensation procedure and the triphenylamine group as the skeleton structure, the new triphenylamine-aromatic aldehyde-succinylhydrazone probe molecule DHBYMH was created. A newly created acylhydrazone probe was structurally characterized by mass spectrometry (MS), NMR, and infrared spectroscopy (FTIR). Fluorescence and UV spectroscopy were used to examine DHBYMH's sensing capabilities for metal ions. Notably, DHBYMH achieved a detection limit of 1.62 × 10-7 M by demonstrating exceptional selectivity and sensitivity towards Cu2+ ions in an optimum sample solvent system (DMSO/H2O, (v/v = 7/3); pH = 7.0; cysteine (Cys) concentration: 1 × 10-4 M). NMR titration, high-resolution mass spectrometry analysis, and DFT computation were used to clarify the response mechanism. Ultimately, predicated on DHBYMH's reversible identification of Cu2+ ions in the presence of EDTA, a molecular logic gate was successfully designed.

Antileakage performance of Schiff base-reinforced thermal energy storage wood for indoor temperature control

Thermal energy storage wood has been rapidly developed as a green and renewable energy-saving building material. In this study, bio-based Schiff bases (VF) were prepared from vanillin and furfurylamine via aldehyde–amine condensation and used as a small molecule fixative. Subsequently, VF and dodecylamine were mixed uniformly and impregnated into rubberwood under pressure, affording thermal energy storage wood (TESW-x%VF). The results revealed that TESW-x%VF exhibited adjustable enthalpy (41.67–88.23 J g−1) and room-temperature phase transition (25°C–27°C). Moreover, the addition of VF improved the antileakage performance of TESW. According to density functional theory calculations, this is because the adsorption energy between VF and dodecylamine molecules has increased by 3–8 times compared to dodecylamine molecules. The above results provide a solution for the leakage issue associated with organic phase-change materials and aid in the future development of energy-saving wood building materials, which also improves the high-value utilization of chemical components in agricultural and forestry crops.

Doxorubicin-based ENO1 targeted drug delivery strategy enhances therapeutic efficacy against colorectal cancer

Alpha-enolase (ENO1), a multifunctional protein with carcinogenic properties, has emerged as a promising cancer biomarker because of its differential expression in cancer and normal cells. On the basis of this characteristic, we designed a cell-targeting peptide that specifically targets ENO1 and connected it with the drug doxorubicin (DOX) by aldehyde–amine condensation. A surface plasmon resonance (SPR) assay showed that the affinity for ENO1 was stronger (KD = 2.5 µM) for the resulting cell-targeting drug, DOX-P, than for DOX. Moreover, DOX-P exhibited acid-responsive capabilities, enabling precise release at the tumor site under the guidance of the homing peptide and alleviating DOX-induced cardiotoxicity. An efficacy experiment confirmed that, the targeting ability of DOX-P toward ENO1 demonstrated superior antitumor activity against colorectal cancer than that of DOX, while reducing its toxicity to cardiomyocytes. Furthermore, in vivo metabolic distribution results indicated low accumulation of DOX-P in nontumor sites, further validating its targeting ability. These results showed that the ENO1-targeted DOX-P peptide has great potential for application in targeted drug-delivery systems for colorectal cancer therapy.

Boosting primary amines renewable tandem synthesis via defect engineering of NiCo alloy

AbstractReductive amination of biomass aldehydes is a vital process to synthesize chemical intermediates primary amine, but the selectivity is severely compromised by the self‐condensation of highly reactive imine intermediates. Herein, we proposed a solution by manipulating the adsorption configuration of secondary imine via defect engineering. Specifically, a gradient reduction strategy was used to adjust the driving force of NiCo alloy crystallization, thus motivating the formation of metal vacancy clusters. The primary amine selectivity was raised from 70.9% to 95.1% with defect concentration increased from 36.1% to 42.5% on catalysts. In situ fourier transform infrared spectroscopy (FTIR) and density functional theory demonstrated metal vacancy clusters induced remarkable NiCo electron transfer, which strengthened electronic coupling between secondary imine with catalyst, resulting in a flat configuration that was conducive to CN bond breakage to guarantee smooth conversion into primary amines. This catalyst exhibited potential real‐life application prospects for its low cost, universality in reductive amination of various aldehydes, and long‐life reusability.

Switchable reductive amination of aldehydes over metal-encapsulated S-1 zeolites with tunable acid-base properties

Catalytic reductive amination of aldehydes is a valuable strategy to synthesize nitrogen-containing compounds but often suffers from low selectivity and complex reaction mechanisms. This study aims to develop a selective control method for the syntheses of primary amines and secondary imines, which are widely used in fine and bulk chemicals, materials, and pharmaceuticals. Metal-encapsulated zeolite is a special type of catalyst that combines the advantages of metal nanoparticles and zeolites, such as high activity and selectivity. Herein, metal-encapsulated zeolites (Pd-M@S-1, M=Ni, Mn, Co) were applied as catalysts for the reductive amination of aromatic aldehydes. Results showed that the reductive amination of aldehydes over Pd-M@S-1 catalysts can be selectively switched between primary amines over Pd0.6@S-1 and secondary imines over Pd0.6Ni@S-1 by tuning the acid-base properties of the catalysts. The effect of acid-base properties of catalysts on selectivity control was claimed by conducting control experiments, time-dependent curves, and detailed characterizations.

Synthesis and catalytic activity of silver N-heterocyclic carbene complexes based on bis(3,5-dimethylpyrazol-1-yl)methyl-substituted pyridylimidazole

A series of N-heterocyclic carbene (NHC) silver complexes derived from 6-[bis(3,5-dimethylpyrazol-1-yl)methyl]-2-pyridylimidazole have been synthesized and characterized by physico-chemical and spectroscopic methods, and the structures of four complexes have been confirmed by X-ray structural analyses. The functionalized NHC is a monodentate ligand in (NHC)AgCl through the carbene carbon atom, and a bridging [C,N,N] tridentate ligand in (NHC)2Ag2(BF4)2 and (NHC)2Ag2(PF6)2 through two pyrazolyl nitrogens and the carbene carbon to form a metallomacrocycle, in which a head (carbene)– to tail (nitrogen) coordination mode to two silver atoms is observed. Preliminary catalytic tests show that these newly synthesized Ag–NHC complexes exhibit excellent catalytic activity at a low catalyst loading (0.1–1 mol%) in the aldehyde–amine–alkyne coupling reaction.

Two novel chiral AIEgens as coordination precursors: synthesis, structures and photophysical study

Two novel chiral molecules, (4S)-5,5-dimethyl-2-(4-oxo-4H-chromen-3-yl)thiazolidine-4-carboxylic acid (OCCA) and (4S)-5,5-dimethyl-2-(4-(1,2,2-triphenylvinyl)phenyl)thiazolidine-4-carboxylic acid (TPCA), were successfully synthesized by aldehyde amine condensation reaction, and their structures were characterized by 1H NMR and single crystal X-ray diffraction. The intensities of photoluminescence changed with the aggregation, exhibiting that OCCA and TPCA are aggregation-induced emission luminogens (AIEgens). After complete aggregation, OCCA emitted the purple-blue light at the peak of 388 nm and TPCA emitted the cyan light at the peak of 488 nm. The aggregation-induced emission (AIE) effects for OCCA and TPCA resulted from local state to twisted intermolecular charge transfer (TICT) and restriction of intramolecular motion (RIM), respectively. Other spectra including UV–vis, IR, and Raman spectra were also discussed in detail.

Artificial nose of scalable plasmonic array gas sensor for Multi-Dimensional SERS recognition of volatile organic compounds

Gas sensing is one kind of promising analytical technique for high-flux screening and evaluation. Volatile organic compounds (VOCs) analysis by surface-enhanced Raman spectroscopy (SERS) is arising but usually focuses on a single species of VOCs due to the limitations of complexity, stability, and accuracy in practical applications. Canine animals have a sensitive sense of smell due to their large number of olfactory cells. Inspired by this, here we innovatively integrate scalable plasmonic arrays and multi-dimensional chemometrics for simultaneous SERS detection of multiple food-borne VOCs. Both direct and indirect SERS strategies are integrated by coating the array surface with MOFs or different monolayers to provide multi-dimensional recognition and readouts. Four species of VOCs including bacterial metabolites, hydrogen sulfide, aldehyde, and biogenic amine were selectively captured and produced unique SERS spectral profiles. The multi-dimensional outputs greatly increase the dimensionality of VOC fingerprints, thereby significantly improving the sensitivity, reliability, and accuracy for freshness discrimination and forecasting in real food smell evaluation. By virtue of multi-dimensional SERS recognition and machine learning, the array gas sensor shows higher accuracy than traditional SERS analysis and is a promising platform for in situ, real-time, and high-flux gas sensing and inspection.

Efficient Electro-catalytic Reductive Amination of Aldehyde over Ru Deposited on Nickel Phosphate

Efficient Electro-catalytic Reductive Amination of Aldehyde over Ru Deposited on Nickel Phosphate

Efficient and chemoselective imine synthesis catalyzed by a well-defined PN3-manganese(II) pincer system.

The highly efficient reductive amination of aldehydes with ammonia (NH3) and hydrogen (H2) to form secondary imines is described, as well as the dehydrogenative homocoupling of benzyl amines. Using an air-stable, well-defined PN3-manganese(II) pincer complex as a catalyst precursor, various aldehydes are easily converted directly into secondary imines using NH3 as a nitrogen source under H2 in a one-pot reaction. Importantly, the same catalyst facilitates the dehydrogenative homocoupling of various benzylamines, exclusively forming imine products. These reactions are conducted under very mild conditions, without the addition of any additives, yielding excellent selectivities and high yields of secondary imines in a green manner by minimizing wastes.