Zero-Dimensional Carbon Nanomaterials for Fluorescent Sensing and Imaging.

Advances in nanotechnology and nanomaterials have attracted considerable interest and play key roles in scientific innovations in diverse fields. In particular, increased attention has been focused on carbon-based nanomaterials exhibiting diverse extended structures and unique properties. Among these materials, zero-dimensional structures, including fullerenes, carbon nano-onions, carbon nanodiamonds, and carbon dots, possess excellent bioaffinities and superior fluorescence properties that make these structures suitable for application to environmental and biological sensing, imaging, and therapeutics. This review provides a systematic overview of the classification and structural properties, design principles and preparation methods, and optical properties and sensing applications of zero-dimensional carbon nanomaterials. Recent interesting breakthroughs in the sensitive and selective sensing and imaging of heavy metal pollutants, hazardous substances, and bioactive molecules as well as applications in information encryption, super-resolution and photoacoustic imaging, and phototherapy and nanomedicine delivery are the main focus of this review. Finally, future challenges and prospects of these materials are highlighted and envisaged. This review presents a comprehensive basis and directions for designing, developing, and applying fascinating fluorescent sensors fabricated based on zero-dimensional carbon nanomaterials for specific requirements in numerous research fields.

Electrochemical Oxidative C-C Bond Cleavage of Ketones for C-N Bond Formation: A Route to Amides.

Herein, we report an efficient electrochemical activation of the C-C bond of aryl ketones for the preparation of amides under catalyst- and external-oxidant-free conditions using aliphatic amines as the N source. Under environmentally benign electrolysis conditions, a series of amides were synthesized in good yield. Our control experiments revealed that electricity plays an important role in this transformation.

Bioactive constituents from Salacia cochinchinensis.

Two new isopimarane diterpenoids, named 1α-hydroxy-7-oxoisopimara-8, 15-diene (1), 11ß-hydroxy-7-oxoisopimara-8(14), 15-diene (2), together with six known compounds (3-8), were isolated from the medicinal plant Salacia cochinchinensis. All isolates were assayed for their cytotoxicity and α-glucosidase inhibitory activity. Results suggested compounds 1, 3 possessed significant cytotoxic activity against HepG2, HL60, and Hela cell lines with IC50 values ranging from 0.23 to 0.35 µM, and compounds 7, 8 exhibited noticeable α-glucosidase inhibitory ability with IC50 values of 0.25 and 0.31 µM, respectively.

Cordatols A-D, four new anti-inflammatory bis-monoterpenoids from Illigera cordata.

Cordatols A-D (1-4), four new limonene-derived bis-monoterpenoids plausibly biosynthesized via hetero-Diels-Alder cyclization and sequential hydrolyses of their monoterpene precursors, were isolated from the aerial parts of Illigera cordata. The structures, including absolute configuration, were established by spectroscopic analysis and further confirmed by a two-steps bioinspired chemical transformation. Moreover, compounds 1-4 exhibited moderate in vitro anti-inflammatory activity with IC50 values ranging from 17.5 to 24.6 µM. This study may provide a novel structural template for potential anti-inflammatory agent discovery.

Synthesis of spiro-tetrahydrothiopyran-oxindoles by Michael-aldol cascade reactions: discovery of potential P53-MDM2 inhibitors with good antitumor activity.

Using proline as the catalyst, an organocatalytic Michael-aldol cascade reaction was developed for the synthesis of spiro-tetrahydrothiopyran oxindoles. The highly functionalized scaffold was assembled in moderate to good yields (51-78%) and excellent diastereoselectivities (>20 : 1 dr). Interestingly, the oxindoles displayed moderate to good in vitro antitumor activities and were validated as p53-MDM2 inhibitors, which represented promising lead compounds for antitumor drug discovery.

Bioactive spirans and other constituents from the leaves of Cannabis sativa f. sativa.

In this paper, 17 compounds (1-17) were isolated from the leaves of Hemp (Cannabis sativa f. sativa). Among the isolates, two were determined to be new spirans: cannabispirketal (1), and α-cannabispiranol 4'-O-ß-D-glucopyranose (2) by 1D and 2D NMR spectroscopy, LC-MS, and HRESIMS. The known compounds 7, 8, 10, 13, 15, and 16 were isolated from Hemp (C. sativa f. sativa) for the first time. Furthermore, compounds 8 and 13 were isolated from the nature for the first time. All isolated compounds were evaluated for cytotoxicity on different tissue-derived passage cancer cell lines through cell viability and apoptosis assay. Among these compounds, compounds 5, 9 and 16 exhibited a broad-spectrum antitumor effect via inhibiting cell proliferation and promoting apoptosis. These results obtained have provided valuable clues to the understanding of the cytotoxic profile for these isolated compounds from Hemp (C. sativa f. sativa).

Novel ferrocene-based bifunctional amine-thioureas for asymmetric Michael addition of acetylacetone to nitroolefins.

An efficient method was developed to synthesize ferrocene-based bifunctional amine-thioureas bearing multiple hydrogen-bonding donors. Asymmetric Michael addition of acetylacetone to nitroolefins catalyzed by these novel bifunctional catalysts affords the Michael adducts in high yield and moderate to excellent enantioselectivities. Multiple hydrogen-bonds play an important role in accelerating the reaction.

Synthesis and anticancer activity of novel quinoline-docetaxel analogues.

A series of novel quinoline-docetaxel analogues (6a-6g, 13a-13g) were designed and synthesized by introducing bioactive quinoline scaffold to C2'-OH of docetaxel. The anticancer activities of these novel analogues were investigated against different human cancer cell lines including Hela, A549, A2780, MCF-7 and two resistant strains A2780-MDR and MCF-7-MDR. The data showed these analogues possessed similar to better cytotoxicity than docetaxel. Compound 6c was found to be the most potent one, and its IC50 value against MCF-7-MDR was 8.8 nM (IC50 of docetaxel was 180 nM). The work indicated that the introduction of quinolyl group in docetaxel could enhance cytotoxicity and reduce drug-resistance.

Bifunctional ferrocene-based squaramide-phosphine as an organocatalyst for highly enantioselective intramolecular Morita-Baylis-Hillman reaction.

This work demonstrates that, in accord with metal catalysis, ferrocene could be an excellent scaffold for organocatalysts. The simple and easily accessible bifunctional ferrocene-based squaramide-phosphine shows high enantioselectivity in the intramolecular Morita-Baylis-Hillman reaction of 7-aryl-7-oxo-5-heptenals, giving a variety of 2-aroyl-2-cyclohexenols in up to 96% ee.

Electrophotocatalytic Tellurosulfonylation of Alkynes for the Synthesis of ß-(Telluro)vinyl Sulfones.

Difunctionalization of alkynes has gained a lot of interest in current organic chemistry. Herein, we developed an electrophotocatalytic multicomponent cascade reaction of alkynes and indoles with sulfinic acid sodium salts using elemental tellurium as the tellurium source. Using synergistic anodic oxidation and visible-light irradiation, various ß-(telluro)vinyl sulfones have been prepared. This strategy features mild reaction conditions, excellent substrate scope, readily available starting materials, and great functional group tolerance.

Application of chiral recyclable catalysts in asymmetric catalysis.

Chiral drugs hold a significant position within the contemporary pharmaceutical market, and the chiral catalysts play a crucial role in their synthesis. However, current chiral catalysts encounter challenges pertaining to their separation from products and the recycling process. The utilization of chiral recyclable catalysts not only reduces production costs but also aligns with the growing emphasis on environmentally-friendly chiral synthetic chemistry. These recyclable catalysts exhibit diverse carriers and distinct characteristics. Chemists employ the distinctive attributes of individual carriers to render them recyclable, thereby yielding time and cost savings. This review examines the asymmetric recyclable catalytic reactions reported between January 2017 and October 2023, categorizing them based on carrier solubility, and elucidates the loading techniques, catalytic impacts, recovery approaches, and recycling processes associated with these carriers.

Spiro-Josiphos Ligands for the Ir-Catalyzed Asymmetric Synthesis of Chiral Amines under Hydrogenation Conditions.

Transition metal-catalyzed asymmetric hydrogenation possesses unparalleled advantages to prepare chiral amines. Here we reported a novel ligand that combined Josiphos and a spirobiindane scaffold and simultaneously investigated its application in Ir-catalyzed asymmetric hydrogenation for the synthesis of chiral amines. Excellent catalytic activity (5000 TON), high enantioselectivity (up to 99% ee), and broad substrate scope (different C═N substrates) make it highly promising for both academic research and industrial applications.

Autophagy stimulates apoptosis in HER2-overexpressing breast cancers treated by lapatinib.

HER2-overexpressing breast cancers often show hyperactivation of the HER2/AKT/mTOR signaling pathway. Lapatinib is an oral dual tyrosine kinase inhibitor (TKI) that targets both EGFR and HER2 to inhibit the proliferation of breast cancer cells. However, it is obscure whether and how lapatinib could induce autophagy in breast cancer cells, an important cell response with drug treatment. In this study, we investigated the apoptosis and the autophagy in the HER2-overexpressing breast cancer cells BT474 and AU565 treated with lapatinib, and further examined their relationship. Lapatinib inhibited the proliferation and the rate of DNA synthesis in HER2-positive cells, as observed by MTT, colony formation and EDU assays. Lapatinib not only induced apoptosis accompanied by an increased expression of cleaved Caspase-3 and cleaved PARP, but it also induced autophagy in vitro, as confirmed by electron microscopy (EM), acridine orange (AO) staining and LC3-II expression. Meanwhile, lapatinib inhibited the phosphorylation of HER2, AKT, mTOR, and p70S6K, whereas that of AMPK was activated. When the cells were pre-incubated with 3-Methyladenine (3-MA), the specific autophagy inhibitor, the growth inhibitory ratio and apoptosis rate were frustrated, whereas colony formation and DNA synthesis ability were encouraged. In addition, 3-MA application could up-regulate Caspase-3 and PARP expression, compared with the treatment with lapatinib alone. The addition of 3-MA could attenuate the inhibitory role on HER2/AKT/mTOR pathway and the active role on AMPK that was raised by lapatinib. Therefore, lapatinib simultaneously induced both apoptosis and autophagy in the BT474 and AU565 cells, and in these settings, autophagy facilitates apoptosis.

6,8-Di-bromo-3-nitro-2-phenyl-2H-chromene.

In the title compound, C15H9Br2NO3, the chromene unit is not quite planar (r.m.s. deviation from planarity = 0.0888 Å). The di-hydro-pyran ring adopts an envelope conformation with the phenyl-substituted C atom fused to the di-hydro-pyran ring as the flap. The dihedral angle between the plane defined by this C atom and the adjacent C and O atoms and the mean plane of the di-hydro-pyran ring excluding the phenyl-substituted C atom is 25.1 (3)°. The dihedral angle between the mean plane of the chromene unit and the phenyl ring is 85.7 (1)°. The crystal structure features C-H⋯O hydrogen bonds and Br⋯O contacts [3.289 (3) Å] involving the nitro O atoms.

Isopropyl 3-phenyl-isoxazole-5-carboxyl-ate.

In the title compound, C13H13NO3, the isoxazole ring is approximately coplanar with the phenyl ring, the dihedral angle between their planes being 7.37 (19)°. In the crystal, centrosymmetrically related mol-ecules are linked into dimers by pairs of C-H⋯O hydrogen bonds, generating a ring of graph-set motif R 2 (2)(10).

One-pot tandem cyclization of enantiopure asymmetric cis-2,5-disubstituted pyrrolidines: Facile access to chiral 10-heteroazatriquinanes.

A series of chiral 10-heteroazatriquinanes were synthesized from enantiopure asymmetric cis-2,5-disubstituted pyrrolidines through a one-pot tandem cyclization procedure. The structures and configurations of these new chiral 10-heteroazatriquinanes are confirmed by X-ray single-crystal diffraction analysis.

Multisite-Sequential Cyclization To Construct 1,2,4-Triazole-Based N-Fused Heterocyclics.

A feasible protocol that uses atomic groups (KSCN, KSeCN, and NH2CN), o-bromobenzoyl hydrazides, and formyls as reaction factors to synthesize N-fused 1,2,4-triazole with benzothiazides, benzoselenazinones, and quinazolinones was proposed. The method overcomes the lengthy multistep synthesis, narrow substrate scope, and toxicity challenge induced by the use or production of hazardous substances. It also enables the development of fused-heterocyclic selenium and quinazolinone derivatives. Their fluorescent performance further demonstrates the practicability of this methodology.

Photocatalytic Cascade Reaction Driven by Directed Charge Transfer over VS -Zn0.5 Cd0.5 S/GO for Controllable Benzyl Oxidation.

Photocatalysis is an important technique for synthetic transformations. However, little attention has been paid to light-driven synergistic redox reactions for directed synthesis. Herein, the authors report tunable oxidation of benzyl to phenylcarbinol with the modest yield (47%) in 5 h via singlet oxygen (1 O2 ) and proton-coupled electron transfer (PCET) over the photocatalyst Zn0.5 Cd0.5 S (ZCS)/graphene oxide (GO) under exceptionally mild conditions. Theoretical calculations indicate that the presence of S vacancies on the surface of ZCS/GO photocatalyst is crucial for the adsorption and activation of O2 , successively generating the superoxide radical (• O2 - ) and 1 O2 , attributing to the regulation of local electron density on the surface of ZCS/GO and photogenerated holes (h+ ). Meanwhile, accelerated transfer of photogenerated electrons (e- ) to GO caused by the π-π stacking effect is conducive to the subsequent aldehyde hydrogenation to benzyl alcohol rather than non-selective oxidation of aldehyde to carboxylic acid. Anisotropic charge transport driven by the built-in electric field can further promote the separation of e- and h+ for multistep reactions. Promisingly, one-pot photocatalytic conversion of p-xylene to 4-methylbenzyl alcohol is beneficial for reducing the harmful effects of aromatics on human health. Furthermore, this study provides novel insights into the design of photocatalysts for cascade reactions.

Efficient synthesis of unnatural dipeptides based on cis-2,5-disubstituted pyrrolidine.

The well-defined unnatural dipeptides based on cis-2,5-disubstituted pyrrolidine backbone were synthesized from commercially available starting materials meso-diethyl-2,5-dibromoadipate, (S)-(-)-1-phenylethylamine, and phenylalanine. The configurations of all the chiral centers in these unnatural dipeptides are confirmed by X-ray crystal diffraction analysis.

Research on Multi-Scale Ecological Network Connectivity-Taking the Guangdong-Hong Kong-Macao Greater Bay Area as a Case Study.

The Guangdong-Hong Kong-Macao Greater Bay Area urban agglomeration is an urban agglomeration with some of the most intensive urbanization since 1980s. A large amount of cultivated land, forest land, water bodies and other land types in the region has been occupied by construction land, resulting in fragmented ecological landscapes and biodiversity in the region and causing many other ecological problems. Based on this, this paper takes the Guangdong-Hong Kong-Macao Greater Bay Area as a case study, constructs an ecological network of the dispersion scale of five species from 1990 to 2020 based on a morphological spatial pattern analysis (MSPA) method, identifies the ecological groups in the network and uses the core node-based community evolution path tracking algorithm to analyze the ecological groups in order to explore the changes of ecological network connectivity at different scales in the region and to reveal the overall and local characteristics and changes of the migratory space of terrestrial mammals with different dispersion capabilities. The research results show that: (1) From 1990 to 2020, the area of construction land in the Guangdong-Hong Kong-Macao Greater Bay Area increased sharply, with good connectivity in the northwest, southwest and eastern regions and poor connectivity in the central region. (2) There are obvious differences between the overall and local changes in the connectivity trends of multi-scale regional ecological networks. On the whole, the overall ecological connectivity of the ecological network at each scale showed a gradual upward trend, and the overall connectivity index IIC and the possible connectivity index PC gradually increased with the increase of the maximum dispersal distance of species. From the perspective of local patches, the larger the species dispersion scale, the larger the value of the revised betweenness centrality index and the patch possible connectivity index. (3) The distribution of ecological groups at different species dispersion scales is different, and the smaller the dispersal scale of the species, the greater the distribution of ecological groups. Small-scale species are limited by the maximum dispersal distance, and the range of their ecological groups is generally small. Small-scale (3 km), mesoscale (10 km) and large-scale (30 km) core nodes of ecological groups show a gradual increase trend, and the overall connectivity of ecological groups has improved. However, the core nodes of the extra-large-scale (60 km) and ultra-large-scale (100 km) ecological groups show a trend of decreasing fluctuations, and the overall connectivity within the ecological group has declined. This study is helpful to clarify the structural characteristics of regional ecological space and provide a theoretical basis for regional ecological planning.