A novel and efficient approach to synthesize 4-(aminomethylene)-1,4-dihydroisoquinolin-3-ones has been developed via a copper(I)-catalyzed coupling reaction between 4-diazo-1,4-dihydroisoquinolin-3-ones and thioamides. This method yields products in good to excellent quantities with remarkable stereoselectivity. Notably, primary and secondary thioamides consistently produce the desired compounds with the (Z)-configuration, whereas tertiary thioamides lead to the formation of products with the (E)-configuration. The versatility and selectivity of this protocol highlight its potential utility in organic synthesis.

An organic base-promoted [3 + 3 + 1] annulation between α-diazo hypervalent iodine(III) reagents and sulfonium ylides has been developed, affording a novel class of highly functionalized 1,3,4-oxadiazepines under mild conditions. This method provides a versatile route for constructing these seven-membered ring systems, which are uncommon in the literature. Furthermore, the reaction can be scaled up, and the resulting product can be successfully converted into polycyclic compounds via the Diels-Alder reaction.

Efficient recovery of value-added compounds from biomass waste represents a sustainable approach to chemical engineering. This study presents an innovative and environmentally benign approach for squalene purification from unsaponifiable soybean oil deodorizer distillate (SODD) waste using biocompatible ionic liquids (ILs) in a liquid-liquid extraction process. Employing a conductor-like screening model for real solvents (COSMO-RS)-guided methodology coupled with a push-and-pull strategy, we systematically screened and identified the optimal biphasic extraction systems. The optimized system utilizing 1 mol % [Ch][C n H2n+1COO] in N-methyl-2-pyrrolidinone achieved exceptional impurity-to-squalene selectivity over 15 while maintaining suitable distribution coefficients. Comprehensive mechanistic investigations through quantum-chemical calculations and nuclear magnetic resonance spectroscopy revealed a hydrogen-bond-dominated separation mechanism. Multistage extraction optimization demonstrated the capability to simultaneously achieve high purity and superior recovery rates of squalene. This research establishes a sustainable, high-performance pathway for valorizing refinery waste streams, offering significant implications for green chemistry and circular economy principles in the biorefinery industry.

A novel copper-catalyzed reaction of 4-diazoisochroman-3-imines and arylboronic acids is reported. This transformation efficiently yields 4-(2-aryl)hydrazono)isochroman-3-imines under mild reaction conditions, showcasing excellent substrate scope and functional group tolerance. Additionally, the versatility of this approach extends to other cyclic diazo compounds, broadening its applicability.

The Suzuki-Miyaura cross-coupling reaction is a cornerstone in organic synthesis, enabling the formation of carbon–carbon bonds with high efficiency and selectivity. This study represents a groundbreaking advancement in the field by pioneering the first enantioselective Ni-catalyzed Suzuki–Miyaura cross-coupling reactions for the synthesis of biaryl atropisomers. Employing a data-driven approach, we have crafted a novel N-protected Xiao-Phos ligand, which, in conjunction with commercially available Ni(COD)2, delivered unparalleled enantioselectivity and reactivity under mild conditions. The ligand design was meticulously guided by an extensive examination of the existing literature on Pd-catalyzed asymmetric Suzuki–Miyaura cross-coupling reactions, directing the virtual screening and subsequent experimental verification of the synthesized ligands in a single iteration. The innovative ligand N-Bn-Xiao-Phos exhibited impressive enantioselectivities coupled with exceptional yields, showcasing versatility with a diverse array of functional groups and aryl boronic acids, and accomplishing successful gram-scale synthesis. DFT computational studies provided profound insights into the reaction mechanism and the roots of enantioselectivity, elucidating the dynamic coordination modes of the chiral ligand and the steric induction. This breakthrough not only broadens the horizons of Ni-catalyzed cross-coupling reactions but also highlights the immense potential of machine learning in the judicious design of chiral ligands for asymmetric synthesis.

This paper describes a new strategy based on fluorescence resonance energy transfer (FRET), in which the rapid synthesis of carbon quantum dots (CQDs) and copper nanoparticles (CuNPs) is used for the determination of tetracycline (TC). Therefore, in this paper, CQDs for fluorescence determination of TC were prepared by microwave heating using chenpi as a carbon source. The prepared CQDs showed good dispersion and uniform spherical shape under transmission electron microscope (TEM), with an average particle size of about 1.91 nm. Under ultraviolet (UV) irradiation, the CQDs emitted bright blue-green fluorescence with a strong fluorescence ( > 1.6 x 10(3) a.u.), and the fluorescence intensity did not change within one week. The emission wavelength of CQDs overlapped with the absorbance of CuNPs, and therefore, CuNPs could burst the fluorescence of CQDs by FRET mechanism. After incubation with TC, the fluorescence of CQDs was restored by the ligand reaction of CuNPs with TC. The assay showed good linearity for TC in the 1-100 nmol/L range, with a determination limit of 0.3554 nmol/L. This study demonstrated the potential of CQDs in antibiotic assays and provided a valuable method for monitoring TC levels.

We present an approach to investigate the localized surface plasmon resonance and surface-enhanced Raman scattering of gold films deposited on uncured polydimethylsiloxane via thermal evaporation. Differing from solid substrates, the liquid surface of uncured polydimethylsiloxane can serve as an isotropic substrate on which gold atoms nucleate and disperse to form characteristic microstructures in a controlled manner. By adjusting experimental parameters during film deposition, the absorption of resonant plasmon modes can be tuned in the visible spectral range due to the control of particle size and distribution in Au films. Furthermore, Raman measurements are conducted to investigate the enhancement of Raman signals in these films, and the experimental results are verified by simulation analysis. This work exhibits tunability of surface plasmon resonance frequency and enhanced Raman detection capability by depositing metal films on liquid surfaces, thus providing potential applications of these films in flexible biosensors and chemical detection.

G-quadruplex is a high-level structure composed of folded DNA or RNA rich in tandem repeats of guanine (G). In recent years, G-quadruplex is widely used in various fields due to its unique structural properties. This article briefly introduces the structural properties of G-quadruplex, and provides a brief introduction to the research on DNA and RNA G-quadruplex in various detection and medical fields. It is hoped that this can provide some help to readers who want to understand G-quadruplex.

近年来，有机发光二极管（OLED）显示屏随着智能手机的普及，逐渐被大众熟知，而用以制备OLED发光显示层的有机荧光材料，其研发过程也吸引了更多研究者的视线。本文按照时间顺序，对有机小分子荧光领域几个重要的发现进行了回顾，以通俗易懂的语言介绍了有机小分子荧光材料的发展过程及一些相关概念。

Objective To evaluate effect of inoculum size of extended-spectrum β-Lactamase (ESBL)-producing-, AmpC-producing-, and KPC-producing Escherichia coli and Klebsiella pneumoniae on the in vitro antibacterial effects of imipenem/relebactam (IMR) and ceftazidime/avibactam (CZA). Methods We compared the impact of inoculum size on IMR and CZA of sixteen clinical isolates and three standard isolates through antimicrobial susceptibility tests, time-kill assays and in vitro PK/PD studies. Results When inoculum size increased from 10 5 to 10 7 CFU/mL, an inoculum effect was observed for 26.3% (5/19) and 52.6% (10/19) of IMR and CZA, respectively; time-kill assays revealed that the concentration of CZA increased from ≥ 4 × MIC to 16 × MIC to reach 99.9% killing rate against K. pneumoniae ATCC-BAA 1705 (KPC-2-, OXA-9- and SHV-182-producing) and 60,700 (SHV-27- and DHA-1-producing). While for IMR, a concentration from 1 × MIC to 4 × MIC killed 99.9% of the four strains. When the inoculum size increased to 10 9 CFU/mL, neither IMR nor CZA showed a detectable antibacterial effect, even at a high concentration. An in vitro PK/PD study revealed a clear bactericidal effect when IMR administered as 1.25 g q6h when inoculum size increased. Conclusion An inoculum effect on CZA was observed more frequent than that on IMR. Among the β-lactamase-producing strains, the inoculum effect was most common for SHV-producing and KPC-producing strains.

Benzoheterodiazole-based fluorophores with aggregation-induced emission (AIE) properties are synthesized and their photophysical properties in different states (solution, film, and powder) are investigated. These compounds present excellent thermal stability, and the decomposition temperature is above 300 °C. Among these compounds, the fluorophores with triphenylamine (TPA) group present better fluorescent emissions in solutions as well as in aggregated states, and the highest solution fluorescent efficiency is up to 75.2% in solution. Meanwhile, the fluorescent compounds terminated with triphenylethene (TPE) exhibit the classical AIE properties. Furthermore, these compounds might be used as emissive layers for the fabrication of red, orange and green organic light emitting diodes.

A catalyst-controlled selective synthesis of benzofuro[2,3-c]isoquinolines and 5,6-dihydro-7H-benzo[c]benzofuro[2,3-e]azepin-7-ones from salicylaldehydes and 4-diazoisoquinolin-3-ones has been developed. The Co(III)-catalyzed reactions furnished benzofuro[2,3-c]isoquinolines as major products, while the Rh(III)-catalyzed reactions afforded 5,6-dihydro-7H-benzo[c]benzofuro[2,3-e]azepin-7-ones as major products.

O-GlcNAcylation is a conserved post-translational modification that attaches N-acetyl glucosamine (GlcNAc) to myriad cellular proteins. In response to nutritional and hormonal signals, O-GlcNAcylation regulates diverse cellular processes by modulating the stability, structure, and function of target proteins. Dysregulation of O-GlcNAcylation has been implicated in the pathogenesis of cancer, diabetes, and neurodegeneration. A single pair of enzymes, the O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), catalyzes the addition and removal of O-GlcNAc on over 3,000 proteins in the human proteome. However, how OGT selects its native substrates and maintains the homeostatic control of O-GlcNAcylation of so many substrates against OGA is not fully understood. Here, we present the cryo-electron microscopy (cryo-EM) structures of human OGT and the OGT-OGA complex. Our studies reveal that OGT forms a functionally important scissor-shaped dimer. Within the OGT-OGA complex structure, a long flexible OGA segment occupies the extended substrate-binding groove of OGT and positions a serine for O-GlcNAcylation, thus preventing OGT from modifying other substrates. Conversely, OGT disrupts the functional dimerization of OGA and occludes its active site, resulting in the blocking of access by other substrates. This mutual inhibition between OGT and OGA may limit the futile O-GlcNAcylation cycles and help to maintain O-GlcNAc homeostasis.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

A series of isochromeno[3,4-d]imidazoles were synthesized in good yields via Rh(II)-catalyzed [3+2] annulation between 4-diazoisochroman-3-imines and oximes. This method involves the formation of rhodium carbene intermediates and elucidates the unique reactivity of oximes under Rh(II) catalysis. Operationally simple and mild reaction conditions with broad substrate diversity, and readily accessible starting materials and rhodium catalyst are the merits of our reaction.

A facile and efficient synthesis of novel 2-(1,2,3,4-tetrahydroisoquinolin-4-yl)-1,3-diarylpropane-1,3-diones via the Sc(OTf)3-promoted reaction between 4-diazo-1,4-dihydroisoquinolin-3-ones and 1,3-dicarbonyl compounds is reported. This formal C–H bond insertion involves an activation of 1,3-dicarbonyl compounds with generation of triflic acid by-product, a formation of diazonium intermediate from diazo component by triflic acid promotion, and a subsequent intermolecular nucleophilic substitution step. Readily available starting materials, cheap catalyst, broad substrate scope (22 examples, up to 92% yield), and mild reaction conditions are the merits of this reaction.

食品防腐剂的出现极大地延长了食品保存的时间，在现代食品工业中占有重要地位。随着生活水平的提高，人们越来越关心食品安全问题，但仍然存在不少误区。本文以拟人化的手法，介绍了几类食品防腐剂的作用原理和利弊，旨在向大众普及科学的防腐剂知识。

An Rh(III)-catalyzed one-pot synthesis of 5H-isochromeno[3,4-c]isoquinolines from readily available 4-diazoisochroman-3-imines and (2-formylphenyl)boronic acids is reported. The cascade annulation involves a Rh(III)-catalyzed cross-coupling and an intramolecular nucleophilic addition-elimination process. A series of biologically important 5H-isochromeno[3,4-c]isoquinolines were obtained in good to excellent yields. The method can be extended to synthesize 7H-isochromeno[3,4-b]thieno[3,2-d]pyridines and 7H-isochromeno[3,4-b]thieno[2,3-d]pyridines from the corresponding heteroaryl boronic acids.

A Rh(III)-catalyzed [4 thorn 1] annulation of aromatic carboxylic acids with 4-diazoisoquinolin-3-ones is reported. A library of highly substituted spiro [isobenzofuran-1,4'-isoquinoline]-3,3'-diones were syn-thesized in moderate to good yields by this protocol (30 examples, up to 84% yield). Broad substrate scope, readily available starting materials, and mild reaction conditions are the merits of this protocol. Moreover, the reaction can be scaled up.(c) 2023 Elsevier Ltd. All rights reserved.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.