Selective Synthesis Research Articles

Trio strategy of harmonizing electronic structure, interface, and microenvironment on amorphous indium oxide nanofiber for selective electrochemical ammonia synthesis

Suppressing parasitic hydrogen evolution reaction (HER) remains a dilemma in developing aqueous electrochemical nitrogen reduction reaction (NRR). Nevertheless, previous studies have revealed the significant challenge of relying solely on electrocatalyst design to pursue selective NRR. Herein, we present a ‘Trio’ strategy to harmonize electronic structures of electrocatalysts, properties of interfaces, and configurations of microenvironments, thereby governing the intricate proton behaviors throughout the reaction, to suppress HER while boosting NRR. As proof-of-concept demonstration, the first designed amorphous In2O3-based nanofiber electrocatalyst, with optimized electronic state by oxygen vacancy and anchoring Mo species, is in conjunction with low-surface-energy monolayer interface and molecular-crowding microenvironment. Such rational synergy creates an advantageous catalytic configuration with decelerated proton diffusion and restricted proton transfer to active sites, thus achieving NH3 yield of 59.72 μg h−1 mg−1 and a FE of 30.60 %. We expect these findings will inspire “collaborative combat” strategies and desirable systems of NRR in the future.

Electro-acidic Catalytic Cascade Reactions for the Efficient and Highly Selective Synthesis of Oxygen Heterocyclic Compounds from Ethylene Glycol

Electro-acidic Catalytic Cascade Reactions for the Efficient and Highly Selective Synthesis of Oxygen Heterocyclic Compounds from Ethylene Glycol

Construction of Difluorinated Cycloheptadienones via Substrate‐Controlled Regioselective Conjugate Addition of Difluoroenoxysilanes to Tropones and Their Anticancer Activity

AbstractThe substrate‐controlled regioselective conjugate addition (1,8‐ and 1,4‐addition) of tropones with difluoroenoxysilanes is reported, which offered an approach for the selective synthesis of multifunctional seven‐membered 3,5‐cycloheptadien‐1‐ones and 1,3‐cycloheptadien‐1‐ones featuring a gem‐difluoroketone moiety. Moreover, these fluorinated cyclo‐heptadienones exhibit effective anti‐proliferative activities (IC50<1 μM) for human colon carcinoma HCT116 cells in vitro, thus providing potential lead compounds for developing new anticancer agents.

Divergent Aromatization of α-Halobenzyl γ-Butenolides Initiated by Selective Enol Protonation to Benzo[c]fluorenones and Naphthalenes.

An unprecedented divergent aromatization reaction of α-halobenzyl γ-butenolides has been described for the selective and concise synthesis of highly substituted benzo and higher π-extended fluorenones, and 1,3-disubstituted naphthalenes depending on the migration ability of the quaternary α-substituent. This aromatization switch from Ag+-mediated planarization to ylidenebutenolides likely originates from selective protonation on the enolic double bond rather than the benzyl halides by TfOH.

The influence of the built environment on drug misuse and abuse

Drug misuse and overdoses (DMO) continue to rise in the United States and around the world. As the COVID-19 pandemic lockdown brought America to a standstill, the drug overdose epidemic took a sharp turn for the worse. Poorly built environments have been said to pose greater risks for substance use. The inequitable race and socioeconomic status distribution of the built environment might be tipping drug overdose and deaths toward minority populations. This review examined the contribution of the built environment to drug misuse and overdose to identify further research and policy needs. Databases like PubMed and Google Scholar were searched for peer-reviewed empirical studies in the English language published from 2010 to March 2021. MeSH search terms were built environment, overdose, drug, and drug overdose. Using the PRISMA flow diagram of article selection, title, and abstract screening plus text narrative synthesis of included articles were done. The built environment features making it more conducive to initiating and maintaining DMO included disinvestment, geographical context (urban versus rural), spatial characteristics of the built environment, easy access to drugs, low access to interventions, and built-environment-associated environmental and social stressors. Built environment features play some roles in drug misuse problems. Policies and programs are needed that place the built environment at the centre of health, drug overdose prevention, and harm reduction, provide increased treatment facilities for addicted persons, ensure stricter opioid prescription measures, and address poverty as well as hopelessness due to disinvestment.

Bimetallic NiSn supported on mesoporous carbon as an efficient catalyst for selective methanol synthesis from CO2

Global warming and climate change represent the most significant environmental challenges of the 21st century, primarily attributed to the rise in CO2 emission in the atmosphere. Efforts to mitigate this increase involve exploring various methods to reduce CO2 levels, with chemical reactions, such as hydrogenation, being a prominent approach. However, the stable and inert nature of CO2 necessitates the use of catalysts to facilitate its conversion. In this research, NiSn nanoparticles with varying atomic ratios were deposited onto a mesoporous carbon support and subsequently utilized as catalysts for CO2 conversion through hydrogenation reactions at ambient pressure. The diffraction patterns of NiSn/MC reveal peaks indicating the presence of a graphitic carbon structure and the existence of a nickel-tin alloy. SEM-EDX mapping and TEM characterization demonstrate the uniform dispersion of NiSn particles on the mesoporous carbon surface, without the formation of agglomerated particles. Catalytic hydrogenation reactions indicate that the atomic ratio of Ni:Sn significantly influences the catalyst activity and selectivity for methanol formation. Among the NixSny/MC catalysts and monometallic Ni/MC, Sn/MC, and NiSn NPs without support, Ni5Sn1/MC demonstrated the highest CO2 conversion of 39.9 %. Additionally, at a reaction temperature of 175 °C and a CO2:H2 gas ratio of 1:7, Ni5Sn1/MC exhibited a methanol yield of 86.31 mmol/gcat, outperforming other catalysts in the study.

Titanocene-catalyzed selective synthesis of 2,4-dialkyl-6-(2-methoxyethyl)pyridines by the reaction of terminal acetylenes with 3-methoxypropionitrile

Titanocene-catalyzed selective synthesis of 2,4-dialkyl-6-(2-methoxyethyl)pyridines by the reaction of terminal acetylenes with 3-methoxypropionitrile

Mesoporous BiCl3 immobilized silicic acid as a stabilized Lewis acid catalyst for the selective synthesis of 4-nitro-o-xylene from the nitration of o-xylene with NO2 under mild conditions

Mesoporous BiCl3 immobilized silicic acid as a stabilized Lewis acid catalyst for the selective synthesis of 4-nitro-o-xylene from the nitration of o-xylene with NO2 under mild conditions

Substrate-modulation effect in on-surface synthesis

The substrate-modulation effect permeates throughout the realm of surface chemistry, particularly in the field of on-surface reactions. A comprehensive understanding of the interactions between molecules and substrates is crucial for the selective synthesis of designed graphene-based materials. In this review, we examine the substrate-modulation effect of surface-assisted reactions, focusing on the reaction mechanisms. We begin by elucidating how the substrates influence various process of the surface-assisted reaction, including adsorption, migration, and reaction of molecules. Additionally, substrates act as charge donors and acceptors to facilitate charge transfer between substrates and molecules, thereby tuning the electronic structure of the molecules.

Near-infrared light-driven biomass conversion.

Current photocatalytic technologies mainly rely on the input of high-energy ultraviolet-visible (UV-vis) light to obtain the desired excited states with adequate energy to drive redox reactions, precluding the use of low-energy near-infrared (NIR) light that occupies ~50% of the solar spectrum. Here, we report the efficient utilization of NIR light by coupling the low-energy NIR photons with reactive biomass conversion. A unique mechanism of photothermally synergistic photocatalysis was revealed for the selective biomass conversion under NIR light. Using biomass-derived 5-hydroxymethylfurfural (HMF) conversion as a model reaction, it was found that NIR and UV-vis light featured markedly different reaction patterns. 5-Formyl-2-furancarboxylic acid (FFCA) was almost exclusively produced under NIR light, whereas UV-vis light favored the formation of 2,5-diformylfuran (DFF) as the major product. This work provides a paradigm for sustainable and selective chemical synthesis using the Earth's abundant resources, sunlight and biomass.

Microwave‐assisted synthesis of 1,4‐disubstituted 1,2,3‐triazole derivatives utilizing NiO/Cu2O nano‐photocatalyst

AbstractBACKGROUNDThe main characteristic features of nickel–copper‐catalyzed azide–alkyne click (Ni‐CuAAC) reactions for production of 1,2,3‐triazoles are regioselectivity and the reaction proceeding under mild conditions. The use of copper salts as catalysts often leads to challenges like contamination of the prepared triazoles. NiO/Cu2O nanocomposites (NCs) were utilized in Ni‐CuAAC reactions as heterogeneous nanocatalysts to achieve the production of some 1,4‐disubstituted 1,2,3‐triazoles in high chemical yields under microwave irradiation.RESULTSThe preparation of NiO/Cu2O NCs was performed through the coprecipitation of NiO nanoparticles on Cu2O surface. The prepared catalyst was used for catalyzing a reaction between benzoyl azides and phenylacetylene under optimized reaction conditions. The NiO/Cu2O NCs exhibited high catalytic activity compared to Cu2O nanoparticles. In addition, by utilizing ethanol–water as the solvent system under microwave irradiation, higher yields and efficient product separation were observed.CONCLUSIONThis study investigated the proficiency of NiO/Cu2O NCs as effective nanocatalysts for the selective synthesis of some 1,4‐disubstituted 1,2,3‐triazole derivatives. Employing heterogeneous nanoparticle catalysts, such as Cu2O and NiO/Cu2O, offers several advantages over homogeneous catalytic systems. These include easier catalyst separation and recovery, potential for catalyst reuse and the ability to fine‐tune the catalytic properties by modulating the nanoparticle composition and structure. © 2024 Society of Chemical Industry (SCI).

Selective N-Methyl Pyrazole Synthesis Enabled by Utopia Point Bayesian Optimization

Selective N-Methyl Pyrazole Synthesis Enabled by Utopia Point Bayesian Optimization

Chalcogen-Based Precursors for Transition Metal (Co, Ni) Phosphides: (Di)chalcogenide-to-Phosphide Transformation via Chemical Extraction of Chalcogenides.

The chemical properties of polymorphic compounds are highly dependent on their stoichiometry and atomic arrangements, making certain phases technologically more important. Selective development of these phases is challenging. This study introduces a method where chalcogenide atoms from metal chalcogenides are chemically extracted by trioctylphosphine (TOP) and substituted with phosphide. Using this approach, dithiocarbamate/xanthate complexes of cobalt and nickel were employed for the selective synthesis of pure metal sulfides or phosphides. Optimization yielded either sulfur-deficient phases (Ni3S2, Co9S8) or a complete transformation to phosphides (Ni2P, CoP). Likewise, for the first time, selenobenzoate complexes of Ni and Co were used for the synthesis of transition metal diselenides (NiSe2, CoSe2), which could then be converted to metal phosphides (Ni2P, Co2P). The synthesis used solution-phase thermal decomposition with various precursors, surfactants, and temperatures. With TOP, different phases of metal chalcogenides, metal phosphides, and mixed metal phosphide nanomaterials (NiS, Ni3S2, Co9S8, NiSe2, CoSe2, Ni2P, Ni5P4, Co2P, CoP, and Ni2-xCoxP) were obtained by varying reaction conditions. The formation mechanism of nickel and cobalt phosphide nanoparticles from precursors is proposed, demonstrating that presynthesized metal chalcogenides can be transformed into phosphides, opening a new research avenue for dimensionally controlled metal chalcogenides as templates for metal phosphides.

Base-Promoted Annulated Aromatization of Aryl Acetylenes with Dimethyl Sulfoxide to Access Symmetrical/Unsymmetric m-Terphenyl.

A protocol for selective and efficient synthesis of symmetrical and unsymmetrical m-terphenyls is presented among aryl acetylene and DMSO in the presence of KOH and methanol. In this reaction, two molecules of aryl acetylene contribute four carbons, and DMSO, as a dual carbon donor, provides two carbons to a new aromatic ring. This protocol can be tolerated for the electron-donating or disubstituted phenylacetylenes as well as the heterocyclic acetylene derivatives.

Selective Synthesis of Deuterated cis- and trans-Isohumulones and trans-Isohumulinones

AbstractDeuterated isohumulones can be prepared directly from humulones by an acyloin ring contraction under either magnesium-catalyzed basic conditions or by photochemical-induced reactions in deuterated solvents. Reactions of humulones with biphasic methylene chloride/aqueous NaOD and MgSO4 in D2O leads to stereoselective formation of cis-d 3-isohumulones (cis/trans ratio of 82:18) as the magnesium salts in yields of 71–83%. Greater than 95% incorporation of three deuterons is observed at the C5 position of the pentenone ring and the methylene position of the C4 acyl group. Photochemical isomerization with a 400 nm blue LED source enables stereospecific formation of deuterated trans-isohumulones in 36–82% yield with greater than 95% incorporation of deuterium at the C5 ring position. Oxidation of humulones with cumene hydroperoxide in basic D2O gives isohumulinones with partial 55–73% incorporation of deuterium due to keto–enol isomerization of the methylene substituent of the C4 acyl group. The structural identities of the deuterated products are determined by a combination of negative-mode electrospray mass spectrometry (MS-ESI–) and 2D heteronuclear proton–carbon HMQC NMR analysis.

AgNOx as Nitrogen Source for [1+1+3] Cycloaddition of Isocyanides with Isocyanates: Selective Synthesis of 1,2,4-Triazoles.

A novel [1+1+3] annulation of AgNOx, isocyanides, and isocyanates for the selective synthesis of 1,2,4-triazoles is presented herein. In this transformation, AgNOx and isocyanates are used as nitrogen sources instead of the traditional hydrazine or diazonium reagents. This process also involves N-O/C-H/C═N bond cleavage and the construction of new N-N/C-N bonds with a good substrate scope and functional group tolerance.

Selective Nitrate Synthesis by Plasma/Liquid Water Reaction: An Enhanced Oxidative Strength Mechanism in Nitrogen Discharge

Selective Nitrate Synthesis by Plasma/Liquid Water Reaction: An Enhanced Oxidative Strength Mechanism in Nitrogen Discharge

Atomic-level rhodium doping into NiO for boosting the selective electrooxidation of HMF to FFCA in neutral electrolyte

The oxidation reaction of the biomass derivative 5-hydroxymethylfurfural (HMF) holds immense promise for the sustainable synthesis of high-value chemicals. Nevertheless, achieving the selective electrooxidation of HMF to generate high value-added formyl-2-furan carboxylic acid (FFCA) intermediate remains a serious challenge. Here, the V-NiO-Rh catalyst was constructed and demonstrates an impressive FFCA selectivity of 71 % for HMF electrooxidation reaction (HMFOR) in neutral electrolyte. The designed experiments elucidate that the HMFOR mechanism is the co-adsorption of OH* and HMF* on Ni active sites. Furthermore, the theoretical calculations prove that the modulation of Ni electronic structure by single atom Rh promotes the ability of HMF adsorption and the water electrolysis to release OH*. This paper establishes a theoretical foundation for the selective synthesis of high value-added intermediates products that are challenging to obtain in alkaline media.

New reaction pathways for high selectivity synthesis of methyl lactate via SnClx(OH)2-x-catalyzed cellulose conversion in water-containing methanol solution

Catalytic conversion of cellulose into lactic acid (LA) is paramount for the emerging biomass-based chemical industry. With emphasis on the reaction mechanism, the catalytic cellulose conversion to methyl lactate (ML) was systematically investigated in water-containing methanol solution. The role that water plays and catalytic mechanism of the acidic and basic sites were analyzed and discussed. It was found that water played an important role in modulating hydrolysis of SnCl2 to release H+ protons and basic SnClx(OH)2-x species. These basic species are very efficient for the isomerization and [3+3] retro aldol condensation in terminal glucose units of cellulose chain, while H+ protons facilitate the ring-opening of the ends of cellulose chains to trioses rather than hydrolysis of the glucoside bonds to form glucose. Based on advanced characterization techniques including ESI-MS, GPC, FT-IR, XRD, XPS and CP-MAS 13C NMR as well as DFT calculations, two new reaction pathways were disclosed for the first time, which are distinct from the well-known traditional pathway that goes through the formation of glucose. Owing to the exclusion of the formation of glucose during the cellulose conversion, the selectivity towards ML can be greatly enhanced. Under optimal conditions, the total selectivity could reach to 91.5 % with a ML and LA yield of 66.3 %. These findings provide new insights into the catalytic conversion of cellulose into value-added chemicals and help explore effective catalysts.

Exploiting Nitroreductases for the Tailored Photoenzymatic Synthesis of Structurally Diverse Heterocyclic Compounds.

N-heterocyclic compounds have a broad range of applications and their selective synthesis is very appealing for the pharmaceutical and agrochemical industries. Herein we report the usage of the flavin-dependent nitroreductase BaNTR1 for the photoenzymatic synthesis of various anthranils and quinolines from retro-synthetically designed o-nitrophenyl-substituted carbonyl substrates, achieving high conversions (up to >99 %) and good product yields (up to 96 %). Whereas the effective production of anthranils required the inclusion of H2O2 in the reaction mixtures to accumulate the needed hydroxylamine intermediates, the formation of quinolines required the use of anaerobic or reducing conditions to efficiently generate the essential amine intermediates. Critical to our success was the high chemoselectivity of BaNTR1, performing selective reduction of the nitro group without reduction of the carbonyl moiety or the activated carbon-carbon double bond. The results highlight the usefulness of an innocuous chlorophyll- and nitroreductase-based photoenzymatic system for the tailored synthesis of diverse N-heterocycles from simple nitro compounds.