High-yield Structure Research Articles

Scandium‐Catalyzed Fischer Indole Synthesis: A Highly Efficient Construction of Complicated Indoles

Herein, we report an efficient scandium‐catalytic reaction protocol for the classical Fischer indole synthesis, which can tolerate a wide variety of polycyclic substrates and allow us to easily construct complex indole structures in high yields for most cases. Moreover, in order to demonstrate the reaction efficacy, we also synthesized two quinazolinone‐containing natural alkaloids, their analog, as well as an anticancer indenoindolone compound.

Enantioselective Synthesis of Axially Chiral Allylic Nitriles via Nickel-Catalyzed Desymmetric Cyanation of Biaryl Diallylic Alcohols.

Axially chiral nitriles are common motifs in organic photoelectric materials, biological compounds, and agrochemicals. Unfortunately, the limited synthetic approaches to axially chiral nitriles have impeded their availability. Herein, we report the first nickel-catalyzed desymmetric allylic cyanation of biaryl allylic alcohols for the synthesis of axially chiral nitrile structures in high yields with excellent enantioselectivities (up to 90% yield and >99% ee). This process enables the synthesis of a diverse range of axially chiral allylic nitriles bearing β,γ-unsaturated alcohol moieties. Leveraging the allylic alcohol and cyano groups as versatile functionalization handles allow for further derivatization of these axially chiral frameworks. Density functional theory (DFT) calculations suggest that both steric and electronic interactions play crucial roles in determining the enantioselectivity of this transformation. Moreover, this mild and facile protocol is also applicable for gram-scale preparation of the chiral nitriles.

Enantioselective Synthesis of Axially Chiral Allylic Nitriles via Nickel‐Catalyzed Desymmetric Cyanation of Biaryl Diallylic Alcohols

Axially chiral nitriles are common motifs in organic photoelectric materials, biological compounds, and agrochemicals. Unfortunately, the limited synthetic approaches to axially chiral nitriles have impeded their availability. Herein, we report the first nickel‐catalyzed desymmetric allylic cyanation of biaryl allylic alcohols for the synthesis of axially chiral nitrile structures in high yields with excellent enantioselectivities (up to 90% yield and >99% ee). This process enables the synthesis of a diverse range of axially chiral allylic nitriles bearing β,γ‐unsaturated alcohol moieties. Leveraging the allylic alcohol and cyano groups as versatile functionalization handles allow for further derivatization of these axially chiral frameworks. Density functional theory (DFT) calculations suggest that both steric and electronic interactions play crucial roles in determining the enantioselectivity of this transformation. Moreover, this mild and facile protocol is also applicable for gram‐scale preparation of the chiral nitriles.

Exploring Heterotropones and Examining Their Propensity to Undergo [4 + 2] Cycloadditions.

An efficient strategy to obtain a broad array of chiral and achiral heterotropones and their corresponding [4 + 2] cycloadducts is disclosed. This strategy enables access to unique heterotropones and intricate bicyclic structures in high yields and diastereoselectivities through a simple procedure and from easily accessible starting materials.

Comparation Review between of Titania (TiO<sub>2</sub>) Synthesis Using CTAC and Fe-TiO<sub>2</sub> Synthesis Using Pluronic P123 as Surfactant

This study reviewed the synthesis of Titania with different shapes in the presence of cetyltrimethylammonium chloride (CTAC) as the famous stabilizer for directly altering the morphology and dimensions. These CTAC stabilizers usually provide the synthesis of Titania with a narrow size distribution and mostly single-crystalline structures in high yields. Many papers on the synthesis of Titania are available. However, only a few articles focus on the synthesis of Titania using CTAC as the stabilizer. The general rule for the shape transformation of Titania by CTAC stabilizer can be easily summarized based on the literature during the last ten year from https://www.sciencedirect.com/ as the data source.

Asymmetric Organocatalytic 1,6-Conjugate Addition of para-Quinone Methides Using [1,2]-Phospha-Brook Rearrangement.

Pudovik addition/[1,2]-phospha-Brook rearrangement as an efficient tool for generation of anionic nucleophiles is an attractive strategy for the construction of C-C bonds in organic synthesis. Herein, we report organocatalytic 1,6-conjugate addition of para-quinone methides utilizing Pudovik addition/[1,2]-phospha-Brook rearrangement. Chiral guanidine-sulfonamide catalyzed the three-component reaction efficiently, providing biologically active oxindole/biaryl/phosphorus-based structures in high yields with excellent diastereo- and enantioselectivities. A possible bifunctional catalytic mode was proposed to elucidate the chiral control of this process.

Architected C70/Graphene Oxide Composites Prepared under Continuous Flow in a Vortex Fluidic Device: Implications for Supercapacitors

Graphene oxide (GO) and fullerene C70 form architected-like C70/GO structures in high yield under continuous flow processing in a vortex fluidic device (VFD). The composite material forms within high-shear regimes in the thin film microfluidic platform, in the absence of surfactants, and indeed in the absence of any auxiliary substances. The structures form on intense micromixing of an o-xylene solution of C70 and a colloidal suspension of GO in dimethylformamide (DMF) at ambient conditions, with the liquids delivered through jet feeds at the same flow rate to the hemispherical base of the rapidly rotating quartz tube in the VFD, which is tilted at 45°. The particle sizes range from 0.5 to 3 μm, with their structure and properties explored using scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, X-ray powder diffraction, and Raman spectroscopy. The mechanism of formation of the architected-like structures is consistent with the general model of fluid flow in the VFD and arises from localized high-shear temperature regimes driving desolvation as the nucleation and growth step for crystallizing the fullerene component, which are then capped with GO.

Influence of basic soil treatment and moisture supply on the structural elements of soybean harvest

The article presents the results of studying the influence of methods of basic tillage and moisture availability on the elements of the structure of the soybean crop: the mass of seeds per plant, the number of beans and seeds per plant, the height of the plant, the weight of 1000 seeds and the yield of soybeans of the Volma variety, after winter wheat. It was found that on average in 2020-2022. Moisture conditions developed in such a way that among the main tillage methods, high yield structure and yield were obtained in the variant with plowing by 22-24 cm - 2.2 t/ha, slightly less yield was obtained by non-moldboard loosening by 22-24 cm - 2 0 t/ha, disking with a processing depth of 16-18 cm produced the least amount of grain - 1.9 t/ha. In addition, it was noted that the method of basic processing affects the amount and dynamics of moisture in the soil during the growing season. During the germination period, the largest moisture reserves were recorded on non-moldboard loosening, and the smallest - on disking. In the flowering phase, when soybean plants urgently need moisture to form a crop, the largest amount of it was in plowing, and the smallest - in disking.

An Alkyne-Isocyanide Cycloaddition/Boulton-Katritzky Rearrangement/Ring Expansion Reaction: Access to 9-Deazaguanines.

An alkyne-isocyanide [3 + 2] cycloaddition followed by a Boulton-Katritzky rearrangement and a ring expansion is demonstrated. Different from the typical Boulton-Katritzky rearrangement, which forms five-membered ring products, the rearrangement-ring expansion method provides a mild, efficient, and atom-economical access to fused 9-deazaguanine structures in high yields.

Coupling biocatalysis with high-energy flow reactions for the synthesis of carbamates and β-amino acid derivatives.

A continuous flow process is presented that couples a Curtius rearrangement step with a biocatalytic impurity tagging strategy to produce a series of valuable Cbz-carbamate products. Immobilized CALB was exploited as a robust hydrolase to transform residual benzyl alcohol into easily separable benzyl butyrate. The resulting telescoped flow process was effectively applied across a series of acid substrates rendering the desired carbamate structures in high yield and purity. The derivatization of these products via complementary flow-based Michael addition reactions furthermore demonstrated the creation of β-amino acid species. This strategy thus highlights the applicability of this work towards the creation of important chemical building blocks for the pharmaceutical and speciality chemical industries.

C-Linked Glycomimetic Libraries Accessed by the Passerini Reaction.

Carbohydrates and their conjugates are the most abundant natural products, with diverse and highly important biological roles. Synthetic glycoconjugates are versatile tools used to probe biological systems and interfere with them. In an endeavor to provide an efficient route to glycomimetics comprising structurally diverse carbohydrate units, we describe herein a robust, stereoselective, multicomponent approach. Isopropylidene-protected carbohydrate-derived aldehydes and ketones were utilized in the Passerini reaction, giving different glycosylated structures in high yields and diastereoselectivities up to 90:10 diastereomeric ratio (d.r). Access to highly valuable building blocks based on α-hydroxy C-glycosyl acids or more complex systems was elaborated by simple post-condensation methodologies.

Breeding value of european oat accessions in the environments of Kuban experiment station of VIR

Background. For the present-day oat breeding, the task is to develop adaptive cultivars with high yield potential, high quality of products, fairly early-ripening habit, and resistance to lodging and diseases. Breeding new cultivars with a complex of valuable characters, high yield, and high quality of products under varied environmental conditions requires well-studied source material. Selection of sources according to the basic economically useful traits is one of the main objectives in the study of the global diversity preserved in the oat collection.Results and conclusion. The article presents the results of studying the oat accessions from Western and Central European countries, preserved in the VIR collection, under the conditions of Kuban Experimental Station of VIR (Krasnodar Terr.). Evaluation of the accessions in the field was targeted at such crop characters as the duration of the growing season, resistance to lodging, and field resistance to rust diseases. A structural analysis was performed in the laboratory to measure the weight of 1000 grains, the number of spikelets and grains per panicle, grain weight per panicle and per plant, and percentage of grain hullness. As a result of a three-year comprehensive field study of the newest oat cultivars bred in Western Europe in the environments of Kuban Experimental Station of VIR, sources of traits useful for breeding were identified, such as lodging resistance, field resistance to crown rust, high yield structure components (1000 grain weight, grain weight per panicle, number of grains per panicle, grain productivity). When using source materials in oat breeding practice, in addition to economically important traits, special attention should be paid to grain size, since this character, according to our data, has the most significant correlation with the grain yield of a cultivar. The identified sources of traits valuable for breeding may be included in breeding programs of Krasnodar Territory and other regions of the Russian Federation.

Synthesis and Characterization of Poly(ether ether ketone-co-benzimidazole)s Based on 2-(2'-Hydroxyphenyl) benzimidazole

A series of novel poly(ether ether ketone)s containing benzimidazole groups with precise structures in high yields were synthesized from various stoichiometric ratio mixtures of m-dihydroxybenzene, 2-(2'- hydroxyphenyl)benzimidazole and 4,4′-difluorodiphenylmethanone via a C–N/C–O coupling reaction process using sulfolane as a solvent. The reaction was carried out at 210°C in the presence of anhydrous potassium carbonate. The structures of the resulted polymers were characterized by means of FTIR, 1H NMR spectroscopy, elemental analysis, and the results were largely consistent with the proposed structure. XRD studies indicated that the resulted polymers are non-crystalline. The polymers have good solubilities in common organic solvents. The polymers showed high glass transition temperatures (Tg = 125–237°C) and high thermal stability (Td5% = 497–539°C in nitrogen, 466–548°C in air). At the same time, as the benzimidazole unit content in the copolymer increased, the thermal properties of the prepared polymers improved. Moreover, the resulted polymers showed good fluorescence properties and the fluorescence emission peak was 465 nm.

From carbon dots to multipods — The role of nickel particle shape and size

In an attempt to synthesize carbon tripod structures in high yield, we have observed that a wide range of carbon structures are formed as the Ni particle size and shape varied. In using trichloroethylene (TCE), acetylene and their mixtures as a carbon source to make carbon materials over Ni nanoparticle catalysts in a chemical vapor deposition (CVD) process, we have observed that the Ni particle size and shape impacts dramatically on the carbon structure formed. The synthesis of the Ni catalyst was achieved by reduction of Ni(acetate)2 with hydrazine (35%). Ex-situ TEM analysis of the reduced NiO particles revealed that the Ni particles underwent a morphological change in the presence of TCE (and H2) with change in (i) temperature (350–750°C) and (ii) H2 flow rate (20–150mL/min) and that this affected the shape of the carbon material that formed. In the absence of TCE only particle sintering occurred. At T=350°C the Ni particles are covered by carbon to form carbon dots. With an increase in T the carbon shapes changed to a bimodal (400°C) and then to a tripod-like structure (450°C) and eventually multipod-like structures (500°C). Carbon fibers were mainly observed for T>500°C. Similar shape changes were observed at 450°C as a function of reaction time and H2 flow rate. It was also found that when acetylene or an acetylene/trichloroethylene mixture was used at T=450°C, helical and linear fibers were produced. The TEM data reveal that the fragmentation and sintering of the Ni (by the carbon source and other factors) to give differently sized Ni particles, especially as it is affected by H2, determines the morphology of the carbon materials grown from the Ni. The TCE has the ability to restructure the Ni particles and this leads to the unusual carbon shapes observed. Thus the carbon and the catalyst influence each other during the growth of the carbon materials.

Preparation and characterization of poly (ether ether ketone)s containing benzimidazolone units

A series of novel poly(ether ether ketone)s containing benzimidazolone groups (PNBEEKs) with precise structures in high yields were synthesized from various stoichiometric ratio mixtures of benzimidazolone, 4,4′-dihydroxybenzophenone and 4,4′-difluorobnzophenone via a C–N/C–O coupling reaction process using sulfolane as a solvent. The reaction was carried out at 210 °C in the presence of anhydrous potassium carbonate. The structures of the resulted polymers were characterized by means of FT-IR, 1H NMR spectroscopy, 13C NMR spectroscopy, and elemental analysis, and the results were largely consistent with the proposed structure. XRD studies revealed that the incorporation of benzimidazolone groups increased the crystallinity of the resulted polymers. At the same time, as the benzimidazolone unit content in the copolymer increased, the solvent resistance properties and thermal properties of the prepared polymers improved. The polymers showed high glass transition temperatures (Tg = 126–221 °C) and high thermal stability (Td5% = 497–593 °C in nitrogen, 466–588 °C in air). Moreover, the resulted polymers showed good fluorescence properties and the fluorescence emission peak was 435 nm.

Patterning nanofibrils through the templated growth of multiple modified amyloid peptides.

There has been considerable interest in the patterning of functionalized nanowires because of the potential applications of these materials to the construction of nanodevices. A variety of biomolecular building blocks containing amyloid peptides have been used to functionalize nanowires. However, the patterning of self-assembled nanowires can be challenging because of the difficulties associated with controlling the self-assembly of these functionalized building blocks. Herein, we present a versatile approach for the patterning of nanowires based on the combination of templated fibril growth with a versatile functionalization method using our structure-controllable amyloid peptides (SCAPs). Using this approach, we have succeeded in the formation of multi-type nanowires with tandem domain structures in high yields. Given that the mixing-SCAP method can lead to the formation of tandem fibrils, it is noteworthy that our method allowed us to control the initiation of fibril formation from the gold nanoparticles, which were attached to a short fibril as initiation points. This approach could be used to prepare a wide variety of fibril patterns, and therefore holds great potential for the development of novel self-assembled nanodevices.

Intramolecular Radical Aziridination of Allylic Sulfamoyl Azides by Cobalt(II)-Based Metalloradical Catalysis: Effective Construction of Strained Heterobicyclic Structures.

Cobalt(II)-based metalloradical catalysis (MRC) has been successfully applied for effective construction of the highly strained 2-sulfonyl-1,3-diazabicyclo[3.1.0]hexane structures in high yields through intramolecular radical aziridination of allylic sulfamoyl azides. The resulting [3.1.0] bicyclic aziridines prove to be versatile synthons for the preparation of a diverse range of 1,2- and 1,3-diamine derivatives by selective ring-opening reactions. As a demonstration of its application for target synthesis, the metalloradical intramolecular aziridination reaction has been incorporated as a key step for efficient synthesis of a potent neurokinin 1 (NK1 ) antagonist in 60 % overall yield.

Intramolecular Radical Aziridination of Allylic Sulfamoyl Azides by Cobalt(II)‐Based Metalloradical Catalysis: Effective Construction of Strained Heterobicyclic Structures

AbstractCobalt(II)‐based metalloradical catalysis (MRC) has been successfully applied for effective construction of the highly strained 2‐sulfonyl‐1,3‐diazabicyclo[3.1.0]hexane structures in high yields through intramolecular radical aziridination of allylic sulfamoyl azides. The resulting [3.1.0] bicyclic aziridines prove to be versatile synthons for the preparation of a diverse range of 1,2‐ and 1,3‐diamine derivatives by selective ring‐opening reactions. As a demonstration of its application for target synthesis, the metalloradical intramolecular aziridination reaction has been incorporated as a key step for efficient synthesis of a potent neurokinin 1 (NK1) antagonist in 60 % overall yield.

Synthesis and properties of polyimides containing N-substituted benzimidazole rings

A series of novel benzimidazole-containing aromatic polyimides with precise structures in high yields were synthesized by the catalyst-free nucleophilic substitution polycondensation of 4,4’-bis(4-fluorophthalimido) diphenyl ether with different molar ratios of 1,4-bis(2-benzimidazolyl) benzene to 4,4’-dihydroxydiphenyl sulfone via a C–N/C–O coupling reaction process. The reaction was carried out at 210°C in the presence of anhydrous potassium carbonate. The structures of the resulting polymers were characterized by means of FTIR, 1H NMR spectroscopy, and elemental analysis, and the results were largely consistent with the proposed structure. DSC and TG measurements showed that the polymers had high glass transition temperatures (T g > 215°C), good thermostability, and high decomposition temperatures (T d5% > 456°C). These novel polymers also showed easy solubility. In addition, the obtained films have good optical transparency, and the mechanical properties exhibited tension strength of 48.2–74.8 MPa and tensile moduli of 1.3–1.9 GPa without any stretching.

Enantioselective Carbene Cascade: An Effective Approach to Cyclopentadienes and Applications in Diels–Alder Reactions

AbstractAn asymmetric carbene cascade reaction, which proceeds through carbene/alkyne metathesis and formal (3+2) cycloaddition and converts alkynyl‐tethered enol diazoacetates to chiral bicyclic cyclopentadienes, is presented; and no catalytic asymmetric version of these carbene cascade transformations has been disclosed so far. The proton signals of the cyclopropene intermediates are observed in the mechanism study, which clearly demonstrate the reaction pathways. In addition, these products are intercepted via Diels–Alder reactions to provide bridged polycyclic structures in high yields and enantioselectivities.magnified image