Search Results (11)

The instability and collapse of boreholes during coal seam gas extraction significantly affect the effectiveness of gas extraction. In response, this study selected human hair residue as the base material for composite protein foaming agents, leveraging the high protein content of animal hoof and hair materials to develop a high-strength, high-permeability, and environmentally friendly new type of foam concrete. This research found that the optimal ratio of foaming agent base solution to water is 1:4 when sodium hydroxide is used for protein hydrolysis. Comparing the foaming effects of sodium dodecyl sulfate (K12), α-sodium alpha-alkenyl sulfonate (AOS), sodium lauryl polyoxyethylene ether sulfate (SLS), and sodium dodecyl benzene sulfonate (LAS), sodium lauryl polyoxyethylene ether sulfate (SLS) exhibited the best foaming performance, while α-sodium alpha-alkenyl sulfonate (AOS) had the best foam stability. The optimal foam performance was achieved by mixing 2.0 g per liter of sodium lauryl polyoxyethylene ether sulfate and 0.3% calcium stearate. The experimental results showed that this foam concrete, with 25 mL of foaming agent, has a high strength exceeding 11 MPa and a high permeability with an average of 2.13 MD. This paper utilizes environmentally friendly materials and preparation processes. By using renewable resources such as human hair residue as raw materials, it helps reduce the dependence on natural resources and promotes sustainable development. This research demonstrates significant sustainability and provides the mining industry with an eco-friendly and efficient solution, with the potential to achieve positive economic and environmental benefits in practical applications. Full article

The fruit of Choerospondias axillaris (Anacardiaceae), known as south wild jujube in China, has been consumed widely in several regions of the world to produce fruit pastille and leathers, juice, jam, and candy. A comprehensive chemical study on the fresh fruits led to the isolation and identification of 18 compounds, including 7 new (1–7) and 11 known (8–18) comprised of 5 alkenyl (cyclohexenols and cyclohexenones) derivatives (1–5), 3 benzofuran derivatives (6–8), 6 flavonoids (9–14) and 4 lignans (15–18). Their structures were elucidated by extensive spectroscopic analysis. The known lignans 15–18 were isolated from the genus Choerospondias for the first time. Most of the isolates exhibited significant inhibitory activity on α-glucosidase with IC₅₀ values from 2.26 ± 0.06 to 43.9 ± 0.96 μM. Molecular docking experiments strongly supported the potent α-glucosidase inhibitory activity. The results indicated that C. axillaris fruits could be an excellent source of functional foods that acquire potential hypoglycemic bioactive components. Full article

An expeditious synthesis of γ- and δ-lactams from tethered alkenyl trichloroacetamides in the presence of 5% of RuCl₂(PPh₃)₃ is reported. In this investigation we have demonstrated that microwave activation significantly enhances reaction rates, leading to the formation of the corresponding lactams in yields ranging from good to excellent. Thus, we have been able to prepare a wide range of lactams, including indole and morphan bicyclic scaffolds, where the corresponding reactions were completely diastereoselective. This process was successfully extended to α,α-dichloroamides without affecting either their yield or their diastereoselectivity. Some of the lactams prepared in this work were evaluated for their hemolytic and cytotoxic responses. All compounds were found to be non-hemolytic at the tested concentration, indicating their safety profile in terms of blood cell integrity. Meanwhile, they exhibited interesting cytotoxicity responses that depend on both their lactam structure and cell line. Among the molecules tested, γ-lactam 2a exhibited the lowest IC₅₀ values (100–250 µg/mL) as a function of its cell line, with promising selectivity against squamous carcinoma cells (A431) in comparison with fibroblasts (3T3 cell line). Full article

A highly chemoselective conversion of α,β-disubstituted nitroalkenes to ketones is developed. An acid-compatible iridium catalyst serves as the key to the conversion. At a 2500 S/C ratio, nitroalkenes were readily converted to ketones in up to 72% isolated yields. A new mechanistic mode involving the reduction of nitroalkene to nitrosoalkene and N-alkenyl hydroxylamine is proposed. This conversion is ready to amplify to a gram-scale synthesis. The pH value plays an indispensable role in controlling the chemoselectivity. Full article

Splice-switching therapy with splice-switching oligonucleotides (SSOs) has recently proven to be a clinically applicable strategy for the treatment of several mis-splice disorders. Despite this, wider application of SSOs is severely limited by the inherently poor bioavailability of SSO-based therapeutic compounds. Cell-penetrating peptides (CPPs) are a class of drug delivery systems (DDSs) that have recently gained considerable attention for improving the uptake of various oligonucleotide (ON)-based compounds, including SSOs. One strategy that has been successfully applied to develop effective CPP vectors is the introduction of various lipid modifications into the peptide. Here, we repurpose hydrocarbon-modified amino acids used in peptide stapling for the orthogonal introduction of hydrophobic modifications into the CPP structure during peptide synthesis. Our data show that α,α-disubstituted alkenyl-alanines can be successfully utilized to introduce hydrophobic modifications into CPPs to improve their ability to formulate SSOs into nanoparticles (NPs), and to mediate high delivery efficacy and tolerability both in vitro and in vivo. Conclusively, our results offer a new flexible approach for the sequence-specific introduction of hydrophobicity into the structure of CPPs and for improving their delivery properties. Full article

The aminocarbonylation of various alkenyl and (hetero)aryl iodides was carried out using tropane-based amines of biological importance, such as 8-azabicyclo[3.2.1]octan-3-one (nortropinone) and 3α-hydroxy-8-azabicyclo[3.2.1]octane (nortropine) as N-nucleophile. Using iodoalkenes, the two nucleophiles were selectively converted to the corresponding amide in the presence of Pd(OAc)₂/2 PPh₃ catalysts. In the presence of several iodo(hetero)arenes, the application of the bidentate Xantphos was necessary to produce the target compounds selectively. The new carboxamides of varied structure, formed in palladium-catalyzed aminocarbonylation reactions, were isolated and fully characterized. In this way, a novel synthetic method has been developed for the producing of N-acylnortropane derivatives of biological importance. Full article

Herein, we developed a simple iron-catalyzed system for the α-alkenylation of ketones using primary alcohols. Such acceptor-less dehydrogenative coupling (ADC) of alcohols resulted in the synthesis of a series of important α,β-unsaturated functionalized ketones, having aryl, heteroaryl, alkyl, nitro, nitrile and trifluoro-methyl, as well as halogen moieties, with excellent yields and selectivity. Initial mechanistic studies, including deuterium labeling experiments, determination of rate and order of the reaction, and quantitative determination of H₂ gas, were performed. The overall transformations produce water and dihydrogen as byproducts. Full article

A series of unsymmetrically substituted oligosilanes were synthesized via stepwise introduction of different substituents to α-chloro-ω-hydrooligosilanes. The reactions of α-chloro-ω-hydrooligosilanes with organolithium or Grignard reagents gave hydrooligosilanes having various alkyl, alkenyl, alkynyl and aryl groups. Thus-obtained hydrooligosilanes were converted into alkoxyoligosilanes by ruthenium-catalyzed dehydrogenative alkoxylation with alcohols. Full article

The Pd(TFA)₂-catalyzed [4+1] annulation of chained or cyclic α-alkenyl-dicarbonyl compounds and unprotected primary amines for “one-pot” synthesis of pyrroles is reported here. Enamination and amino-alkene were involved in this practical and efficient tandem reaction. The annulation products were isolated in moderate to excellent yields with O₂ as the terminal oxidant under mild conditions. In addition, this method was applied to synthesize highly regioselective aminomethylated and di(1H-pyrrol-3-yl)methane products. Full article

A procedure has been developed for synthesis of 2-alkenyl-2H-indazoles starting from 2-(2-carbonylmethyl)-2H-indazoles, which are prepared by gallium/aluminium- and aluminium-mediated, direct, regioselective alkylation of indazoles with α-bromocarbonyl compounds. The structure of 3-(2H-indazol-2-yl)-2H-chromen-2-one was proven by X-ray crystallography. The styrene- and coumarin-2H-indazoles produced by using the new method were found to have interesting fluorescence properties. Full article

The lithiation of 2-(2,2-dimethyl-1,3-dioxolan-4-yl)ethyl diisopropylcarbamate (1) is achieved freely by sec-butyllithium in diethylether with high lk-diastereoselectivity: the bicyclic chelate complexes 3a and 3b are reacted with electrophiles to form optically active precursors 4a and 4b with >95% diastereoselectivity. In addition, tertiary diamines can undergo an external complexation in contest with the internal oxygen ligand, leading to improved stereoselectivities. The further reactions of lithiated carbamates with trans alkenyl-9-BBN derivatives after 1,2 metallate rearrangements, gave the key intermediate α-substituted allylic boranes 7. Subsequent allylboration of aldehydes gave (Z)-anti-homoallylic alcohols 8 in good yield and excellent d.r. Full article