An Organic EnT Photocatalyst 4CzMeBN and the Application in the Synthesis of cis-Fused Azetidines.

A powerful EnT photocatalyst 4CzMeBN has been developed and utilized in the synthesis of cis-fused azetidines via dearomative [2+2] cycloaddition under visible light. The photocatalyst 4CzMeBN is a donor-acceptor cyanoarene and features high triplet state energy and long lifetime of triplet state, which would be an alternative to widely used EnT photocatalyst Ir[dF(CF)ppy](dtbbpy)PF. The photochemical [2+2] cycloaddition provides a facile method to synthesize valuable dihydroisoquinolone-fused azetidines with high efficiency.

NIR Diradical-Featured Croconaine Nanoagent for Cancer Photoacoustic Imaging and Photothermal Therapy.

Radical-featured organic materials usually demonstrate significantly narrower bandgap than that of regular organic materials, which is beneficial for near-infrared (NIR) absorption and non-radiative decay process, making them good candidates for photothermal agents (PTAs) of photothermal therapy (PTT). However, most organic radicals are too short-lived to be separated and stable. Herein, a stable pyrylium-croconaine (CR) dye CR845 with high diradical character was synthesized and assembled into CR845 nanoparticles (NPs) to explore the photoacoustic imaging (PAI) and photothermal therapeutic performance under NIR irradiation in vitro and in vivo.

Fabrication of core-shell nanostructure via novel ligand-defect reassembly strategy for efficient photocatalytic hydrogen evolution and NO removal.

The core-shell structure often exhibits unique properties, resulting in superior physical and chemical performance distinct from individual component in the field of photocatalysis. However, traditional prepared methods such as template synthesis and layer-by-layer self-assembly are relatively complex. Therefore, it is necessary to explore an efficient and expedient approach.

Asiaticoside improves depressive-like behavior in mice with chronic unpredictable mild stress through modulation of the gut microbiota.

Background: Asiaticoside, the main active ingredient of Centella asiatica, is a pentacyclic triterpenoid compound. Previous studies have suggested that asiaticoside possesses neuroprotective and anti-depressive properties, however, the mechanism of its anti-depressant action not fully understood. In recent years, a growing body of research on anti-depressants has focused on the microbiota-gut-brain axis, we noted that disruption of the gut microbial community structure and diversity can induce or exacerbate depression, which plays a key role in the regulation of depression.

Diastereoselective Access to Ester-Substituted -Phenanthridinones via Hydrogen Atom Transfer-Involved 1,7-Enyne Bicyclization.

An organophotoredox-catalyzed 1,7-enyne bicyclization for the cis-diastereoselective synthesis of ester-substituted phenanthridinones has been achieved through radical cascade cyclization involving 1,6-hydrogen atom transfer. This transition-metal- and oxidant-free one-pot protocol generates three distinct C-C bonds and two quaternary carbon centers.

Construction of 2D/2D S-scheme BiMoO/Zn-TCPP heterojunction via in-situ self-assembly growth strategy to enhance interface effect for efficient photocatalytic hydrogen production.

Two-dimensional/two-dimensional (2D/2D) heterojunctions are considered to be an effective strategy for forming strong interface effects and facilitating photogenerated carrier separation. However, it is usually limited by the size mismatch of the materials, even at the expense of its redox capability. Herein, 2D/2D S-scheme heterojunction photocatalyst BiMoO/Zn-TCPP (BMO/ZTP) composed of 2D BiMoO and 2D Zn-TCPP (TCPP: tetrakis (4-carboxyphenyl) porphyrin) (MOFs) was constructed by in-situ self-assembly growth strategy.

Visible light-enabled synthesis of phosphorylated indolizine and pyridoindole derivatives HAT-mediated radical cascade cyclization.

A visible light-enabled cascade cyclization strategy is disclosed with concomitant phosphorylation and heterocycle construction. It provides a novel and environmentally benign approach for accessing tetrahydroindolizine-containing phosphonates under metal-free conditions. Mechanistic studies revealed that phosphinoyl radicals were generated from H-phosphonates a HAT process.

Photoredox-Catalyzed Three-Component 1,2-Cyanoalkylpyridylation of Styrenes with Nonredox-Active Cyclic Oximes.

Three-component alkene 1,2-difunctionalizations have emerged as a powerful strategy for rapid buildup of diverse and complex alkylpyridines, but the distal functionalized alkyl radicals for the alkene 1,2-alkylpyridylations were still rare. Herein, we report an example of regioselective three-component 1,2-cyanoalkylpyridylation of feedstock styrenes with accessible nonredox-active cyclic oximes through visible-light photoredox catalysis, providing a series of structurally diverse β-cyanoalkylated alkylpyridines. This protocol proceeds through a radical relay pathway including the generation of iminyl radicals enabled by phosphoranyl radical-mediated β-scission, radical transposition through C-C bond cleavage, highly selective radical addition, and precise radical-radical cross-coupling sequence, thus facilitating the regioselective formation of two distinct C-C single bonds in a single-pot operation.

NIR squaraine dyes for dual colorimetric and fluorescent determination of Fe, Cu, and Hg ions.

Four benzoindolenine-based squaraine dyes (SQs), which have the advantages of intense visible and near-infrared (NIR) absorption and emission ( 663-695 nm, 686-730 nm) were synthesized and characterized by UV-vis absorption, fluorescent emission spectrophotometry, FTIR, NMR and HRMS analysis. Among them, BBSQ showed excellent performance, which exhibited high selectivity to Fe, Cu, and Hg in acetonitrile solution even in the presence of other competitive metal ions, accompanied by obvious color change easily detected by the naked eye. The detection limit was 14.

Catalytic C-H alkynylation of benzylamines and aldehydes with aldimine-directing groups generated .

Iridium-catalysed regioselective C-H alkynylation of unprotected primary benzylamines and aliphatic aldehydes has been achieved using in situ-installed aldimine directing groups. This protocol provides a straightforward route for the synthesis of the alkynylated primary benzylamine and aliphatic aldehyde derivatives, featuring good substrate compatibility and high regioselectivity.

Chemodivergent photocatalytic access to 1-pyrrolines and 1-tetralones involving switchable C(sp)-H functionalization.

A chemodivergent photocatalytic approach to 1-pyrrolines and 1-tetralones from alkyl bromides and vinyl azides has been developed through chemoselectively controllable intermolecular [3 + 2] and [4 + 2] cyclization. This photoredox-neutral two-component protocol involves intermolecular radical addition and switchable distal C(sp)-H functionalization enabled by iminyl radical-mediated 1,5-hydrogen atom transfer. Meanwhile, chemoselectivity between C(sp)-N bond formation and C(sp)-C(sp) bond formation is precisely switched by photocatalysts (Ru(bpy)(PF) vs.

Redox-neutral and metal-free synthesis of 3-(arylmethyl)chroman-4-ones visible-light-driven alkene acylarylation.

A metal- and aldehyde-free visible-light-driven photoredox-neutral alkene acylarylation with readily available cyanoarenes is described. A variety of 3-(arylmethyl)chroman-4-ones (i.e.

Molecular Docking, Molecular Dynamics Simulations, and Free Energy Calculation Insights into the Binding Mechanism between VS-4718 and Focal Adhesion Kinase.

Focal adhesion kinase (FAK) is a 125 kDa nonreceptor tyrosine kinase that plays an important role in many carcinomas. Thus, the targeting of FAK by small molecules is considered to be promising for cancer therapy. Some FAK inhibitors have been reported as potential anticancer drugs and have entered into clinical development; for example, VS-4718 is currently undergoing clinical trials.

Indole and Pyrrole Derivatives as Pre-photocatalysts and Substrates in the Sulfonyl Radical-Triggered Relay Cyclization Leading to Sulfonylated Heterocycles.

A visible-light-induced method for the construction of heterocyclic scaffolds such as pyrido[1,2-]indoles and indolizines via sulfonyl radical-triggered relay cyclization without employing any external photocatalyst has been developed. Preliminary mechanistic investigation indicated that indole and pyrrole derivatives could serve as pre-photocatalysts to promote the sulfonylation/cyclization, thereby providing a facile method to synthesize valuable sulfonylated heterocycles.

Hydrogen bond serving as a protecting group to enable the photocatalytic [2+2] cycloaddition of redox-active aliphatic-amine-containing indole derivatives.

Redox-sensitive functionalities such as aliphatic amines with low oxidation potentials and easily oxidized by photocatalysts are generally not compatible with photocatalytic reactions. We describe a hydrogen-bond-assisted visible-light-mediated [2+2] cycloaddition of redox-sensitive aliphatic-amine-containing indole derivatives providing a range of cyclobutane-fused polycyclic indoline derivatives, especially bridged-cyclic indolines. Mechanistic studies indicated that the success of the reaction was based on on the formation of H-bonds between the N-atom and alcohol proton of TFE or HFIP, with this formation preventing or blocking the single-electron transfer from the aliphatic amine functionality to the excited photocatalyst.

Neodymium oxide (NdO) coupled tubular g-CN, an efficient dual-function catalyst for photocatalytic hydrogen production and NO removal.

Graphitic carbon nitride (g-CN) has emerged as a most promising photocatalyst, non-toxicity and low density, but it is plagued by low activity due to the small specific surface area and poor quantum efficiency. Morphological engineering and coupling with other materials to form hybrids have proven to be effective strategies for enabling high photocatalytic performances. Here, neodymium oxide (NdO) coupled tubular g-CN composites had been facilely synthesized by a solvent evaporation and high-temperature calcination method to realize efficient photocatalytic activity of hydrogen production and NO removal.

Preparation and evaluation of a molybdenum disulfide quantum dots embedded C18 mixed-mode chromatographic stationary phase.

Molybdenum disulfide quantum dots (MoS QDs) were chosen as a functional two-dimensional material to improve the separation performance of a traditional C18 column. In this work, MoS QDs were synthesized by the combination of sonication and solvothermal treatment of bulk MoS. The prepared MoS QDs were characterized by transmission electron microscope (TEM), Zeta potential measurement, UV-visible absorption and fluorescence spectroscopy.

Highly Enantioselective Synthesis and Anticancer Activities of Chiral Conjugated Diynols.

A chiral amino alcohol based ligand was found to promote the highly enantioselective addition of terminal conjugated diynes to aromatic and aliphatic aldehydes. The combination of easily available C -symmetric (R)- and (S)-BINOL with Ti(OiPr) , Zn powder, and EtI was also found to catalyze the asymmetric addition of 1,3-diynes to aldehydes under mild reaction conditions, and thus, both enantiomers of the chiral conjugated diynols could be prepared with high enantioselectivities. The resulting optically active conjugated diynols were found to have potential anticancer activities with significant differences against HepG2 and HeLa cancer cells, and remarkable enantioselective cytotoxicity was observed for the first time.

Enhanced Turnover for the P450 119 Peroxygenase-Catalyzed Asymmetric Epoxidation of Styrenes by Random Mutagenesis.

A randomized library is constructed based on pET30a-CYP119-T214V plasmid. This library of random mutants of CYP119-T214V was screened by means of the reduced CO difference spectra and epoxidation of styrene. By using directed evolution, a new CYP119 quadruple mutant S148P/I161T/K199E/T214V is constructed, expressed, and purified.

HPLC Determination of Enantiomeric Purity for 1-Styrene-3-Hexyl Propynol.

A rapid and sensitive high performance liquid chromatography method was developed and validated for the determination of enantiomeric purity of 1-styrene-3-hexyl propynol. Baseline separation with resolution greater than 2.0 was achieved within 17 min on a CHIRALCEL OD-H (25 cm × 0.

Engineering P450 Peroxygenase to Catalyze Highly Enantioselective Epoxidation of cis-β-Methylstyrenes.

P450 119 peroxygenase and its site-directed mutants are discovered to catalyze the enantioselective epoxidation of methyl-substituted styrenes. Two new site-directed P450 119 mutants, namely T213Y and T213M, which were designed to improve the enantioselectivity and activity for the epoxidation of styrene and its methyl substituted derivatives, were studied. The T213M mutant is found to be the first engineered P450 peroxygenase that shows highly enantioselective epoxidation of cis-β-methylstyrenes, with up to 91 % ee.

Total Synthesis of Chiral Falcarindiol Analogues Using BINOL-Promoted Alkyne Addition to Aldehydes.

An enantioselective total synthesis of chiral falcarindiol analogues from buta-1,3-diyn-1-yltriisopropylsilane is reported. The key step in this synthesis is BINOL-promoted asymmetric diacetylene addition to aldehydes. The two chiral centers of the falcarindiol analogues can be produced by using the same kind of catalyst with high selectivity, and the final product can be obtained in only six steps.

Gas chromatography-mass spectrometry/selected ion monitoring for screening asymmetric epoxidation of styrene.

A screening method by gas chromatography-mass spectrometry (GC-MS) with selected ion monitoring (SIM) has been developed for asymmetric epoxidation of styrene. All samples were analyzed by GC-MS with the mode of SIM by using ethylbenzene as the internal standard, by which styrene and styrene epoxide enantiomers were completely separated and their concentrations were accurately determined. Furthermore, this method was used to evaluate the epoxidation reaction of styrene, which was optimized by orthogonal experiment.

2-Methyl-1,2,4-triazolo[4,3-a]pyridin-2-ium tetra-fluoroborate.

In the title salt, C7H8N3 (+)·BF4 (-), the 1,2,4-triazolo[4,3-a]pyridinium cation is planar [maximum deviation of 0.016 (2) Å for all non-H atoms]. The cation and anion constitute a tight ionic pair with an F⋯N [2.