Metal- and light-free decarboxylative direct C-H alkylation of heteroarenes at room temperature.

This study reports a metal- and light-free decarboxylative C-H alkylation of heteroarenes at room temperature. The reaction generates various primary, secondary, and tertiary alkyl radicals and functionalizes seven different privileged scaffolds widely present in bioactive molecules. During this process, one equivalent of hypervalent iodine(III) carboxylates (HICs) plays dual roles as an alkyl radical precursor and an oxidant.

Strategies for the Construction of Benzobicyclo[3.2.1]octane in Natural Product Synthesis.

Benzobicyclo[3.2.1]octane is a cage-like unique motif containing a bicyclo[3.2.1]octane structure fused with at least one benzene ring. It is found in various natural products that exhibit structural complexities and important biological activities. The total synthesis of natural products possessing this challenging structure has received considerable attention, and great advances have been made in this field during the past 15 years. This review summarizes thus far achieved chemical syntheses and synthetic studies of natural compounds featuring the benzobicyclo[3.2.1]octane core. It focuses on strategic approaches constructing the bridged structure, aiming to provide a useful reference for inspiring further advancements in strategies and total syntheses of natural products with such a framework.

3D Printing Technique Fortifies the Ultradeep Hydrodesulfurization Process of Diesel: A Journey of NiMo/Al2O3-MMT.

In this contribution, we rationally designed and controllably fabricated a NiMo/Al2O3-montmorillonite (3D-NiMo/Al2O3-MMT) monolithic catalyst via a 3D printing strategy with economical montmorillonite (MMT) as a binder. The catalytic performance of the resulting NiMo/Al2O3-MMT for 4,6-dimethyldibenzothiophene (4,6-DMDBT) hydrodesulfurization (HDS) was evaluated. The experimental results unveil that the 3D-NiMo/Al2O3-MMT monolithic catalyst exhibits robust stability and exceptional HDS activity with 99.2% 4,6-DMDBT conversion (residual 4 ppm of S), which is remarkably superior to that of conventional NiMo/Al2O3 (61.5%), NiMo/MMT (63.2%), and even NiMo/Al2O3-MMT (76.5%) prepared by the mechanical-mixing method. This should be ascribed to the synthetic effect between the MMT binder and the Al2O3 substrate, which effectively weakens the interaction between the Mo species and the Lewis acids on the original Al2O3 surface, thereby significantly increasing the content of reducible Mo species and considerably facilitating the formation of more highly active NiMoS phase (Type II) with optimal average stacking layers and thereafter remarkably enhancing the ultradeep HDS activity of the 3D-NiMo/Al2O3-MMT monolithic catalyst.

Chinese Herbal Medicine for the Treatment of Adult Viral Myocarditis: An Overview of Systematic Reviews and Meta-analyses of Randomized Controlled Trials.

PURPOSE: Viral myocarditis (VMC) is a life-threatening disease that can affect all ages and genders, with middle-aged adults being particularly susceptible. Numerous systematic reviews have been conducted to investigate the efficacy and safety of Chinese herbal medicine (CHM) in treating adult viral myocarditis (AVM). The objective of this study was to conduct a comprehensive overview of systematic reviews and meta-analyses of randomized controlled trials (RCTs) regarding the efficacy and safety of CHM for AVM. METHODS: A comprehensive systematic search was conducted across 8 electronic databases from their inception to June 23, 2022, augmented by manual searches of the gray literature. Systematic reviews were independently selected and data extracted in accordance with predetermined criteria by 2 reviewers. Included systematic reviews were assessed for methodologic and reporting quality using Assessing the Methodological Quality of Systematic Reviews 2 and Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The quality of evidence relating to outcome measures was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation tool. Recalculation of effect sizes and subsequent determination of 95% CIs were conducted with either a fixed-effects or random-effects model. FINDINGS: The current overview of systematic reviews included a total of 6 systematic reviews, which reported on 67 RCTs with a participant pool of 5611 individuals. The findings of our study indicate that the combination of CHM and Western medications had positive effects on the effective rate, cure rate, ECG recovery, atrial premature contraction/premature ventricular contraction, left ventricular ejection fraction, myocardial enzymes, and improvement of clinical symptoms for AVM. The adverse drug reactions in the combination therapy group were generally less than or lighter than that in the Western medication group (relative risk = 0.79; 95% CI, 0.44-1.40; P > 0.05, I2 = 0). IMPLICATIONS: Our research results provide evidence that combining CHM with Western medicine could offer potential benefits for patients with AVM. However, the number of studies included in our review is limited and the methodologic quality of these studies is modest. Therefore, there are potential uncertainties regarding the conclusion that CHM with Western medication may benefit patients with AVM. We call for more large-scale, high-quality studies with standardized designs to further verify and support our findings. This would promote a better understanding of the efficacy and safety profile of CHM and provide reliable reference evidence for clinical practice and policy making. Moreover, future research should explore optimal drug combinations, examine therapeutic doses and durations of CHM combination therapy, and evaluate its long-term efficacy and safety.

Three-Step Synthesis of the Antiepileptic Drug Candidate Pynegabine.

Pynegabine, an antiepileptic drug candidate in phase I clinical trials, is a structural analog of the marketed drug retigabine with improved chemical stability, strong efficacy, and a better safety margin. The reported shortest synthetic route for pynegabine contains six steps and involves the manipulation of highly toxic methyl chloroformate and dangerous hydrogen gas. To improve the feasibility of drug production, we developed a concise, three-step process using unconventional methoxycarbonylation and highly efficient Buchwald-Hartwig cross coupling. The new synthetic route generated pynegabine at the decagram scale without column chromatographic purification and avoided the dangerous manipulation of hazardous reagents.

Asymmetric Total Synthesis of Naphthospironone A.

Naphthospironone A, a polyhydroxy cagelike bioactive natural product, was synthesised for the first time in this study. The spiro[bicyclo[3.2.1]octane-pyran] core was constructed by an acid-promoted epoxide-opening lactonisation and a base-induced intramolecular aldol-type cyclisation.

Graphene Interlocking Carbon Nanotubes for High-Strength and High-Conductivity Fibers.

Carbon nanotubes (CNTs) are promising building blocks for the fabrication of novel fibers with structural and functional properties. However, the mechanical and electrical performances of carbon nanotube fibers (CNTFs) are far lower than the intrinsic properties of individual CNTs. Exploring methods for the controllable assembly and continuous preparation of high-performance CNTFs is still challenging. Herein, a graphene/chlorosulfonic acid-assisted wet-stretching method is developed to produce highly densified and well-aligned graphene/carbon nanotube fibers (G/CNTFs) with excellent mechanical and electrical performances. Graphene with small size and high quality can bridge the adjacent CNTs to avoid the interfacial slippage under deformation, which facilitates the formation of a robust architecture with abundant conductive pathways. Their ordered structure and enhanced interfacial interactions endow the fibers with both high strength (4.7 GPa) and high electrical conductivity (more than 2 × 106 S/m). G/CNTF-based lightweight wires show good flexibility and knittability, and the high-performance fiber heaters exhibit ultrafast electrothermal response over 1000 °C/s and a low operation voltage of 3 V. This method paves the way for optimizing the microstructures and producing high-strength and high-conductivity CNTFs, which are promising candidates for the high-value fiber-based applications.

Grafting macromolecular chains on the surface of graphene oxide through crosslinker for antistatic and thermally stable polyethylene terephthalate nanocomposites.

The graphene oxide (GO) and polyethylene terephthalate (PET) molecular chains are connected together by the two amino groups of the crosslinking agent p-phenylenediamine (PPD). The presence of macromolecular chains could make GO uniformly dispersed in the polymer matrix, improving the antistatic performance and thermal stability of the nanocomposite. In this paper, GO was prepared by the improved Hummers, method. In the first step, an amine group of PPD undergoes a nucleophilic ring-opening reaction with an epoxy group on GO. Multiple characterization methods indicate that PPD is successfully grafted to the surface of GO sheets and GO is partially reduced simultaneously. The graphene layer spacing increased from 0.81 nm for GO to 1.49 nm for grafted graphene oxide (g-GO). The number of oxygen-containing functional groups in GO is also reduced. The conductivity of g-GO at room temperature is 1.8 S cm-1, which is much higher than that of GO. In addition, the thermal stability of g-GO has also been improved. In the second step, the other unreacted terminal amino group of PPD is grafted to PET molecular chains through hydrogen bonding or amidation reactions. Antistatic and thermally stable nanocomposites were then obtained by hot pressing. Different ratios of graphene/polyester nanocomposites were obtained. At the same time, the g-GO is further thermally reduced. The thermal stability of PET/g-GO nanocomposite has been greatly improved, while the thermal stability of PET/GO nanocomposite is basically the same as that of pure PET. For the PET/g-GO nanocomposite, the residue rate has increased by nearly 10%, and the maximum thermal decomposition temperature has also increased by 11 °C. When the content of g-GO is 1.0 vol%, the bulk conductivity of PET/g-GO nanocomposite is increased by 8 orders of magnitude. However, when the content of GO is 1.0 vol%, the bulk conductivity of the PET/GO nanocomposite is only improved by 3 orders of magnitude. PET/g-GO nanocomposites exhibit good antistatic properties. The PET/g-GO nanocomposite's conductive percolation threshold is 0.61 vol%, while that of the PET/GO nanocomposite is 1.64 vol%. The electrical conductivity of the nanocomposite increases with the increase of graphene content. And the well-dispersed modified graphene can improve the electrical conductivity of the nanocomposite.

Long-pulsed neodymium-doped yttrium-aluminum-garnet laser versus cryotherapy for the treatment of cutaneous warts: A randomized controlled trial.

BACKGROUND: Observational studies have shown promising therapeutic effects of long-pulsed neodymium-doped yttrium-aluminum-garnet (LP-Nd:YAG) laser on warts. OBJECTIVE: To evaluate whether LP-Nd:YAG laser was superior to cryotherapy for cutaneous warts. METHODS: In this study, 150 adult patients with warts were randomized equally to receive laser or cryotherapy every 3 to 4 weeks, for a maximum of 4 sessions. The primary outcomes were the cure rates at 16 weeks and 6 months; secondary outcomes included time to clearance of warts and treatment-related adverse effects. RESULTS: There was no difference in the cure rate for laser versus cryotherapy at 16 weeks (54.1% vs 46.7%, respectively) and 6 months (59.5% vs 57.3%, respectively). However, time to clearance of warts, up to 16 weeks and 6 months, tended to be shorter for laser versus cryotherapy (P = .04 and .08, respectively). Post hoc analyses showed a significantly higher cure rate for laser versus cryotherapy in 3 subgroups of human papillomavirus 2/27/57-induced recalcitrant warts but not in their counterpart subgroups. Laser had more mild adverse effects. LIMITATIONS: Single center. CONCLUSIONS: The overall therapeutic effects of LP-Nd:YAG laser were similar to cryotherapy, but laser may be more effective to relatively recalcitrant warts and may be associated with shorter time to clearance of warts.

Preparation of Triple-Functionalized Montmorillonite Layers Promoting Thermal Stability of Polystyrene.

The objective of this study was to investigate the effect of three different treatments on the morphology, microstructure, and the thermal characteristics of a montmorillonite (Mt) sample, by using hydrochloric acid (HCl), tributyl tetradecyl phosphonium chloride (TTPC) surfactant, and γ-methacryloxypropyltrimethoxysilane (γ-MPS). The resultant nanofillers were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption-desorption analysis, X-ray fluorescence spectrometry (XRF), and thermogravimetric analysis (TGA). The results showed that the amount of chemical grafting of the γ-MPS was increased after the acid treatment, whereas the amount of intercalation of the TTPC surfactant was decreased. The preintercalation of TTPC or silylation of γ-MPS, for the Mt sample, had a certain hindrance effect on its subsequent silylation or intercalation treatments. Furthermore, the effect of four different nanofillers on the thermal stability properties of the polystyrene (PS) matrix were also investigated. The results showed an increase in thermal stability for the triple-functionalized Mt, compared with the double-functionalized samples. The onset decomposition temperatures and the maximum mass loss temperatures of the PS nanocomposites were increased by 27 °C and 32 °C, respectively, by the incorporation of triple-modified Mt, as a result of the good exfoliation and dispersion of the nanolayers, more favorable polymer-nanofiller interaction, as well as the formation of a more remarkable tortuous pathway in the continuous matrix.

Strategies and Efforts towards the Total Synthesis of Palhinine Alkaloids.

The palhinine family of Lycopodium alkaloids were first reported in 2010, which feature an intriguing isotwistane carbon cage and a nine-membered azonane ring. It is noteworthy that the tetracyclic 5/6/6/9 skeleton was unprecedented in Lycopodium alkaloids before their seminal discovery. Over the past decade, extensive synthetic efforts stemming from seven research groups have resulted in two racemic total syntheses to date. This review article takes the opportunity to survey these efforts and achievements so as to promote further research towards the asymmetric total synthesis of palhinine alkaloids.

Rhodium-Catalyzed Ring-Opening Hydroacylation of Alkylidenecyclopropanes with Chelating Aldehydes for the Synthesis of γ,δ-Unsaturated Ketones.

The first intermolecular ring-opening hydroacylation of alkylidenecyclopropanes with chelating aldehydes through a rhodium-catalyzed acrylamide-promoted protocol is reported. This highly efficient catalytic system enables the direct synthesis of a diverse range of linear γ,δ-unsaturated ketones. Good functional group compatibility is demonstrated for the completely atom-economical and remarkably selective proximal C-C bond cleavage process. Mechanistic studies reveal that the bidentate coordination of N,N-dimethylmethacrylamide (L1) to the acylrhodium intermediates might facilitate the cyclopropane ring fragmentation and isomerization.

Preparation and properties of amphiphilic hydrophobically associative polymer/ montmorillonite nanocomposites.

In this research, a novel amphiphilic hydrophobically associative polymer nanocomposite (ADOS/OMMT) was prepared using acrylamide (AM), sodium 4-vinylbenzenesulfonate (SSS), N, N'-dimethyl octadeyl allyl ammonium bromide (DOAAB) and organo-modified montmorillonite (OMMT) through in situ polymerization. Both X-ray diffraction patterns and transmission electron microscopy images verified the dispersion morphology of OMMT in the copolymer matrix. Then, the effect of the introduction of OMMT layers on the copolymer properties was studied by comparing with pure copolymer AM/SSS/DOAAB (ADOS). The thermal degradation results demonstrated that the thermal stability of the ADOS/OMMT were better than pure copolymer ADOS. During the solution properties tests, ADOS/OMMT nanocomposite was superior to ADOS in viscosifying ability, temperature resistance, salt tolerance, shear resistance and viscoelasticity, which was because OMMT contributed to enhance the hydrophobic association structure formed between polymer molecules. Additionally, the ADOS/OMMT nanocomposite exhibited more excellent interfacial activity and crude oil emulsifiability in comparison to pure copolymer ADOS. These performances indicated ADOS/OMMT nanocomposite had good application prospects in tertiary recovery.

Toward the total synthesis of grayanane diterpene mollanol A by a Prins [3 + 2] strategy.

Toward the total synthesis of a novel grayanoid, mollanol A, we developed a concise convergent strategy based on a formal [3 + 2] cyclization initiated by the Prins reaction. In this key intermolecular reaction between an unprotected hydroxyaldehyde and activating-group-free olefins, two chiral carbons and one densely substituted tetrahydrofuran ring were constructed stereoselectively.

Enantioselective Synthesis and Antifungal Activity of C18 Polyacetylenes.

Fungal pathogens cause serious crop diseases and decrease crop yields and quality. Polyacetylene alcohols are plant secondary metabolites and bioactive against various pathogenic fungi. They are, however, difficult to synthesize. In the present study, an efficient and highly enantioselective method (>98% ee) was established and employed to achieve the synthesis of the natural C18 polyacetylenes (S,E)-octadeca-1,9-dien-4,6-diyn-3-ol 1, (3R,10R,E)-octadeca-1,8-dien-4,6-diyne-3,10-diol 2, and their analogs. The title compounds were structurally characterized and biologically evaluated for fungicidal activities. The compounds exhibited high potencies against eight pathogenic fungal species tested, such as Colletotrichum gloeosporioiles, Bipolaris sorokiniana, Fusarium graminearum, and Fusarium pseudograminearum, with half-maximum effective concentrations ranging from 8 to 425 µg/mL, being similar to those of the fungicide thiophanate-methyl (3-408 µg/mL). These compounds are potential natural fungicides and fungicide lead candidates for further structural and property improvements.

K2S2O8-mediated radical cyclisation of 2-alkynylthioanisoles or -selenoanisoles: a green and regioselective route to 3-nitrobenzothiophenes and benzoselenophenes.

An acid, transition-metal, and chromatography-free radical nitration/cyclisation of 2-alkynylthioanisoles or -selenoanisoles has been developed. This is the first example of the use of highly unstable 2-nitrovinyl radicals for C-S bond formation. This facile route efficiently produces 3-nitrobenzothiophenes and benzoselenophenes, which are difficult to access via classical methods. Density functional theory (DFT) calculations were carried out to probe the reaction mechanism. The resulting products were tested for their in vitro anti-tuberculosis activity, and compounds 2d and 2l showed significant activities against sensitive and drug-resistant strains.