Excellent Yields Research Articles

Effect of heat treatment on the microstructure, mechanical properties and tribological behavior of Ti-45Nb alloy fabricated by laser powder bed fusion

To avoid stress-shielding effects between biomedical implants and human bones, low modulus heat-treated Ti-45Nb specimens fabricated by laser powder bed fusion (LPBF) after annealing heat treatment were studied in this study. The microstructure and mechanical properties of the specimens revealed that (i) the as-built specimen consisted mainly of the β-TiNb phase, and heat treatment did not affect the phase species, demonstrating the thermal stability of the LPBFed Ti-45Nb alloy. (ii) After heat treatment, all the specimens exhibited excellent yield strengths (over 1100 MPa), and low Young's moduli (approximately 80 GPa). (iii) The specimens exhibited excellent wear resistance with the main wear modes of abrasive and adhesive wear and low COF (0.353-0.394) under a load of 20 N.

Rational design of nitrogen-doped carbon for palladium catalysts in hydrogenation of hydrazo compounds

We synthesized CN11, a carbon nitride material rich in sp3 hybrid graphitic nitrogen (sp3-N), employing a facile oxalic acid-assisted melamine molecular assembly strategy. CN11 promoted the formation of Pd nanoparticles (NPs) predominantly exposing {200} facets, termed Pd/CN11-2. This facet-specific configuration significantly boosted hydrogen adsorption, leading to notable improvements in catalytic activity. Compared to Pd/XC-72-2 and Pd/g-C3N4-2, Pd/CN11-2 exhibited a remarkable two-fold and nineteen-fold increase in catalytic yield for hydrazo compound hydrogenation, respectively. Pd/CN11-2 also demonstrated robust performance across a range of reaction conditions, maintaining excellent yield. This study emphasizes the critical role of tailored support structures in controlling Pd NPs facets, thereby enhancing hydrogenation efficiency. It provides valuable insights for advancing the industrial application of Pd-based catalysts, underscoring the importance of strategic support modulation for optimizing catalytic performance.

Copper nitrate as a powerful and eco-friendly natural catalyst for mediator-free aerobic oxidation of 2,3-dihydroquinazolinones and 1,4-dihydropyridines under mild conditions

For the first time, copper (II) nitrate trihydrate was used as an efficient, eco-friendly, operational ease, inexpensive, and commercially available catalyst for the biomimetic aerobic oxidation synthesis of quinazolinones and Hantzsch pyridines from their corresponding 2,3-dihydroquinazolinones and 1,4-dihydropyridines, respectively. The products were achieved in satisfactory to excellent yields using acetonitrile as the solvent. These methods are considered to be more eco-friendly, efficient, uncomplicated, and useful compared to existing ones as they align with various principles of green chemistry. Hence, these techniques can be utilized in pharmaceuticals and other delicate synthesis processes.

Evading the strength-ductility trade-off dilemma in high-entropy alloy by lamellar structure

Constructing lamellar structures in high-entropy alloys (HEAs) is an effective strategy for addressing the inherent trade-off between strength and ductility. However, conventional processing methods often struggle to achieve precise control over the microstructures and mechanical properties of the lamellar structures. Here, we employ laser remelting technology to successfully fabricate a lamellar structure within an HEA. The lamellar HEA shows an excellent yield strength of ∼547 MPa with a large uniform elongation of ∼41 %. Such enhanced strength-plasticity synergy is mainly attributed to the hetero-deformation of lamellar structures.

β‐Cyclodextrin‐SO3H as a Supramolecular Catalyst for Efficient Greener Synthesis of Substituted Bis(6‐aminouracil‐5‐yl)methanes in Water

AbstractA simple, straightforward, and highly efficient greener approach for synthesizing bis(6‐aminouracil‐5‐yl)methane derivatives was developed by employing β‐cyclodextrin‐SO3H as supramolecular catalyst in water at 100 °C. A total of 16 bis(6‐aminouracil‐5‐yl)methanes were synthesized via a one‐pot reaction between substituted aromatic aldehydes, 6‐amino‐1,3‐dimethyluracil, and 10% β‐cyclodextrin‐SO3H in water with 84%–92% yield within 20–120 min. The salient features of this protocol included water as green solvent, β‐cyclodextrin‐SO3H as recyclable supramolecular catalyst, mild reaction conditions, easy isolation of pure products, and good to excellent yields.

One-pot multicomponent photo-induced eosin-Y catalyzed synthesis of 2-amino oxa/thiazine derivatives

An effective and advantageous one-pot multicomponent photo-induced methodology has been developed for the synthesis of biologically potent 2-amino-4H-1,3-oxa/thiazine from substituted benzaldehyde, ethynylbenzene and urea/thiourea catalyzed by eosin-Y at room temperature using EtOH as a green solvent with wide range of applications in pharmaceutical and agriculture industries. This proposed work emphasizes to investigate an accessible, safe, easy and convenient method for the synthesis of 2-amino oxa/thiazine derivatives with good to excellent yield.

Metal-Free Synthesis, Single Crystal Analysis and Photophysical Behavior of p-Terphenyls

A simple and convenient metal-free approach for synthesizing p-terphenyls 7a–f is presented through a carbanion-induced ring transformation reaction involving 6-biphenyl-2H-pyran-2-ones 5 with pyruvic acetyl dimethyl aldehyde 6. Further the prepared dimethoxy p-terphenyls 7b-c,f were converted into diethoxy p-terphenyls 8a-c. The base-mediated ring transformation reactions proceeded smoothly under mild reaction conditions, resulting the formation of ring transformation products 7a-f and 8a-c in good to excellent yields. This synthetic approach allows the incorporation of both electron-withdrawing and electron-donating functionalities into p-terphenyl framework. Moreover, the structure of compound 7a was confirmed by its single crystal X-ray analysis. Additionally, the photophysical properties of synthesized p-terphenyls were analysed using UV-visible and fluorescence spectroscopy. Interestingly, the synthesized p-terphenyls 7a–f showed blue fluorescence in chloroform. The solvatochromic behaviour and concentration studies of compound 7d was also perforemd. Additionally, the thermal stability characteristics of compound 7d was also studied using TG and DTA analysis.

Efficient synthesis of novel phenanthroline-dimedone derivatives using Pd@HQBI-SPION as a versatile palladium-immobilized catalyst

This paper presents the synthesis and application of a novel catalyst for carbon–carbon bond formations, comprising palladium immobilized on 2-(5-hydroxyquinolin-8-yl)-1H-benzo[d]imidazole-5-carboxylic acid modified superparamagnetic iron oxide nanoparticles (Pd@HQBI-SPION). The synthesis involved the attachment of HQBI ligands to SPION using APTES, followed by the immobilization of palladium. Characterization techniques, including FTIR, TEM, and magnetic measurements, confirmed the successful synthesis and structural integrity of Pd@HQBI-SPION. The catalytic activity of Pd@HQBI-SPION was evaluated in various carbon–carbon bond formation reactions, demonstrating high efficiency and reusability. 8 different derivatives bearing several electron withdrawing and electron donating functionalities were used as starting materials and the products were obtained in high isolated yields (75–97%). The catalyst exhibited excellent performance in one-pot synthesis of phenanthroline-dimedone polycyclic derivatives via C-alkylation followed by intramolecular O-alkylation of phenanthroline with dimedone. The products are obtained in high to excellent yields is described. This protocol presents a highly selective synthetic method for the construction of polycyclic aromatic compounds containing nitrogen and oxygen atoms.

Programmable Piperazine Synthesis via Organic Photoredox Catalysis.

Piperazine cores have long been identified as privileged scaffolds in the development of pharmaceutical compounds. Despite this, the facile synthesis of diverse C-substituted piperazines remains a challenge without prefunctionalized substrates/cores. Herein, we describe a programmable approach to highly diversifiable piperazine cores, which circumvents the typical need for radical precursors. The use of organic photoredox catalysis renders this method operationally simple, as direct substrate oxidation followed by 6-endo-trig radical cyclization with in situ generated imines may furnish the product. Additionally, the photoredox-catalyzed anti-Markovnikov hydroamination of readily accessible ene-carbamates provides a modular approach to functionalized diamine starting materials which are shown to generate more complex piperazine cores. A wide range of both carbonyl and amine condensation partners were shown to be compatible with this system in good to excellent yield.

Pd/IPrBIDEA‐Catalyzed Synthesis of Pyrroles via Cascade C−C/C−F Cleavage/Annulation of gem‐Difluorocyclopropanes

AbstractA regioselective cascade C−C/C−F cleavage/annulation of gem‐F2CPs with enaminones catalyzed by Pd/IPrBIDEA is reported. The NHC ligand IPrBIDEA plays a pivotal role in enhancing the reaction efficiency. With this protocol, a variety of fully substituted pyrroles were obtained in good to excellent yields. Furthermore, this approach facilitates the modification of some bioactive scaffolds.

Syntheses of Novel Spirobenzazepinoindole Derivatives via Lewis-Acid Catalyzed Pictet-Spengler Cyclization.

The syntheses of novel spirobenzazepinoindole derivatives has been achieved through a highly efficient and synthetic route. The approach involves a two-step reaction, utilizing indole derivatives, 2-amino benzyl alcohol, and ninhydrin as key starting materials under mild reaction conditions. The reaction proceeds via a sequential cascade process involving cyclization, condensation and spiro-annulation, leading to the formation of the spirobenzazepinoindole core structure in good to excellent yields. The method offers broad substrate scope, high atom economy, and operational simplicity. The synthesized spirobenzazepinoindoles were fully characterized by spectroscopic techniques, including NMR (1H & 13C), IR and mass spectrometry. The methodology provides a valuable tool for the rapid generation of structurally complex spirobenzazepinoindoles, which could serve as scaffolds for the development of new therapeutic agents.

Palladium‐Catalyzed Cyclization/Thiocarbonylation for the Synthesis of Thioester‐Substituted Benzofurans with S‐Aryl Thioformates as the Thioester Sources

AbstractA palladium‐catalyzed cyclization and thiocarbonylation reaction is disclosed for the synthesis of thioester‐containing benzofurans. By using S‐aryl thioformates as efficient and convenient thioester surrogates, a variety of thioester‐functionalized benzofurans were formed in moderate to excellent yields with very good functional group tolerance. This protocol features mild reaction conditions, broad substrate scope, and no manipulation of toxic CO gas and odorous thiols.

Synthesis of C-N or C-C Spiroindolines via Rearrangement Coupling Reaction.

Herein, we report a general approach to effectively construct C-N or C-C spiroindolines using tetrahydro-β-carbolines as starting materials via a rearrangement coupling reaction. This method is characterized by its operational simplicity and mild conditions. Notably, a wide range of anilines and indoles are suitable for this intermolecular coupling, yielding the corresponding C-N or C-C spiroindolines in good to excellent yields.

Anti-Selective Carboacylation of Alkynes via Photoredox/Nickel Dual Catalysis.

Here, we report an intermolecular carboacylation of terminal alkynes with tertiary and secondary alkyltrifluoroborates as well as acyl chlorides via photoredox/nickel dual catalysis, affording a varity of stereodefined trisubstituted enones in good to excellent yields and E stereoselectivity, through a radical relay process. This redox-neutral protocol exhibits excellent functional group tolerance, exclusive regio- and stereoselectivity, and broad compatibility with various acyl chlorides and alkyltrifluoroborates.

CuxOy Incorporated COF: A Potential Reusable Catalyst for the Synthesis of α‐Hydroxy Ketones and Oxazolidinones Under Atmospheric CO2 Pressure and Solvent‐Free Conditions

AbstractIn this present work, a newly designed metal‐oxide nanoparticle incorporated Covalent organic framework (COF), CuxOy@TFP‐ODA has been successfully synthesized and used for the effective synthesis of Oxazolidinones and a‐hydroxy ketones under mild conditions utilizing CO2. Initially, imine‐linked 2D COF, TFP‐ODA was synthesized by simple solvothermal method followed by the embedment of copper oxide nanoparticles (NPs) into the skeleton of the as‐synthesized COF. Different characterization techniques were employed to establish the physical and chemical characteristics of both CuxOy@TFP‐ODA and TFP‐ODA COF materials. To study the catalytic efficiency of the highly porous CuxOy@TFP‐ODA, three components coupling reaction involving primary amine, propargyl alcohol and CO2 to synthesize a series of 2‐Oxazolidinone and synthesis of α‐hydroxy ketones using CO2 as a Co‐catalyst were carried out over the as‐prepared catalyst under green and sustainable conditions which illustrated excellent yields and selectivity of the corresponding products. The synthesized catalyst was proved to be completely heterogeneous and especially, the catalyst material demonstrated significant potential for reuse across several catalytic cycles.

A Ru-Based Complex for Sustainable One-Pot Tandem Aerobic Oxidation-Knoevenagel Condensation Reactions.

Our novel binuclear complex-anchored Ru(III) catalyst, designed and assembled by sonicating 2,2'-(4,6-dihydroxy-1,3-phenylene)bis(1H-benzo[d]imidazole-4-carboxylic acid), Ru(DMSO)4Cl2 and 4-methylpyridine, demonstrates remarkable efficiency and selectivity. It promotes one-pot reactions, including active methylenes and benzyl alcohols in water, via a tandem aerobic oxidation/Knoevenagel condensation process, yielding benzylidene malononitrile in excellent yields. The catalyst's ability to oxidize benzyl alcohols to aldehydes, which then undergo Knoevenagel condensation with active methylenes, makes it a multifunctional catalyst. Notably, the catalyst can be successfully retrieved and recycled for five successive rounds with no significant decrease in catalytic efficiency. The ICP study showed that no catalyst leaching was observed, indicating that the designed catalyst is indeed heterogeneous. The Ru catalyst outperformed other documented catalysts in terms of lower dose, shorter duration, decreased working temperature, and the absence of dangerous additives. This demonstrates the catalyst's robustness and sustainability, making it a promising candidate for future organic conversions and industrial uses.

CuI–Zn(OAc)2 Catalyzed Selective CC Bond Cleavage of 1,3‐Diketones/β‐Ketoester for the Formation of Quinazolin‐4(3H)‐Ones: A Fast, Solvent‐Free, Synthetic Strategy Under Microwave Irradiation

ABSTRACTCuI–Zn(OAc)2 catalyzed a new, fast, solvent‐free strategy for the synthesis of quinazolin‐4(3H)‐ones via selective scission of CC bond of the 1,3‐diketone (both cyclic and acyclic) and β‐ketoester was achieved under microwave irradiation. In contrast to the frequently applied synthetic strategy that involves cyclization‐oxidation sequence of anthranilamides (2‐aminobenzamides) with various aldehydes or benzyl alcohols, here, anthranilamide reacts with β‐ketoester/1,3‐diketo compounds in presence of CuI‐Zn(OAc)2 catalyst to form quinazolin‐4(3H)‐ones scaffold through an uncommon CC bond cleavage under solvent‐free mild conditions with excellent yields. Besides, this method displays its capacity for gram‐scale reactions.

Interrupted Michael Reaction: Sulfophosphinoylation of α,β-Unsaturated Ketones Catalyzed by Phosphine.

An efficient method for phosphine-catalyzed sulfophosphinoylation of α,β-unsaturated ketones for synthesis allylic organophosphorus compounds has been reported, in which α,β-unsaturated compounds acting as zwitterions react with electrophiles and nucleophiles to form a C-P bond and a C-O bond and obtain allylic organophosphorus with high regio- and stereoselectivity in moderate to excellent yields.

Stereodivergent Synthesis of Aldol Products Using Pseudo-C2 Symmetric N-benzyl-4-(trifluoromethyl)piperidine-2,6-dione.

The present article describes the successful performance of crossed aldol reactions of the CF3-containing pseudo-C2 symmetric cyclic imide with various aldehydes. The utilization of HMPA as an additive attained the preferential formation of the anti-products in good to excellent yields, which contrasts with our previous method without this additive, proceeding to furnish the corresponding syn-isomers. The effective participation of ketones and α,β-unsaturated carbonyl compounds in reactions with this imide was also demonstrated to expand the application of this imide.

Copper‐Catalyzed Enantioselective Dehydro‐Diels–Alder Reaction: Atom‐Economical Synthesis of Axially Chiral Carbazoles

AbstractThe dehydro‐Diels–Alder (DDA) reaction is a powerful method for the construction of aromatic compounds. However, the enantioselective DDA reaction has been rarely developed, probably due to the competitive thermal reaction. Herein, we report a copper‐catalyzed enantioselective DDA reaction through vinyl cation pathway. The reaction leads to the atom‐economical synthesis of axially chiral phenyl and indolyl carbazoles in generally excellent yields with good to excellent atroposelectivities. This methodology represents the first example of non‐noble metal‐catalyzed enantioselective DDA reaction. Notably, new chiral ligand and organocatalyst derived from the constructed axially chiral carbazole are demonstrated to be useful in asymmetric catalysis.