Abstract In recent years, China has organized three batches of high-proportion renewable energy generation bases, with the aim of resolving the geographical imbalance between renewable energy supply ...and consumption. Renewable electricity is transported from the resource-abundant western regions to the electricity-demanding eastern regions. Given the inherent variability and unpredictability of wind power and photovoltaic power generation, there is a pressing need for additional support from more reliable energy generation sources, including coal-fired power and concentrated solar power (CSP). This paper presents a power system optimization planning model that incorporates the internal energy transfer of CSP. It proposes strategies for establishing high-proportion renewable energy generation bases supported by both coal-fired power and CSP. Furthermore, it investigates the primary constraints affecting the energy generation base. The study also compares the peak shaving depth and output characteristics between coal-fired power and CSP. Moreover, this paper introduces the method of natural gas supplemental combustion to enhance the power supply stability of CSP, enabling the renewable energy generation base to supply electricity through conventional DC transmission.
An efficient cascade reaction of tryptamine‐derived isocyanides with C,N‐cyclic azomethine imines is described. The polycyclic pyrrolo2,3‐cquinoline derivatives, which benefited from rearrangement ...process driven by hydrogen bonding, could be directly assembled in moderate to good yields (40–87 %) under metal‐free and mild conditions. This transformation involved four new heterocyclic rings formations and uniquely, ring opening of indole as well as ring expansion of C,N‐cyclic azomethine imine. Both experimental and DFT studies provided guidance on the in‐depth insight into the reaction pathways and hydrogen bonding was identified to lower the free energy barrier in transition states. This work constitutes a rare example of tryptamine‐derived isocyanide‐based cascade reactions, and potentially could be a powerful synthetic strategy for accessing polycyclic analogues involved in natural products.
Natural‐product‐like polycyclic pyrrolo2,3‐cquinoline derivatives have been easily constructed in one‐step process from easily available starting materials. This reaction involves two ring enlargements and four heterocyclic ring formations via cascade rearrangement process. DFT studies reveal the crucial hydrogen‐bonding interaction in the detailed mechanistic investigation.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
An inverse‐electron‐demand Diels–Alder (IEDDA) reaction could complement the conventional normal‐electron‐demand Diels–Alder reaction in the synthesis of six‐membered carbocycles. However, catalytic ...asymmetric all‐carbon‐based IEDDA reactions are underdeveloped. Herein, we disclosed a copper‐catalyzed asymmetric IEDDA reaction using electron‐deficient 3‐carboalkoxyl‐2‐pyrones and electronically unbiased indenes as reactants. This method enables the rapid and enantioselective construction of a wide range of hexahydrofluorenyl bridged‐lactone scaffolds. Using this method, asymmetric total syntheses of cephanolides A and B were accomplished.
Catalytic asymmetric all‐carbon‐based inverse‐electron‐demand Diels–Alder reactions of 2‐pyrones with electronically unbiased indenes have been realized. This method enables the rapid and enantioselective construction of a wide range of hexahydrofluorenyl bridged‐lactone scaffolds. Based on this method, asymmetric total syntheses of cephanolides A and B have been accomplished.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Non‐small‐cell lung cancer (NSCLC), with its aggressive biological behavior, is one of the most diagnosed cancers. Tumor‐associated inflammatory cells play important roles in the interaction between ...chronic inflammation and lung cancer, however the mechanisms involved are far from defined. In the present study, by developing an orthotopic NSCLC mouse model based on chronic inflammation, we proved that an inflammatory microenvironment accelerated the growth of orthotopic xenografts in vivo. Tumor‐associated macrophages, the most abundant population of inflammatory cells, were identified. Treatment with macrophage‐conditioned medium (MCM) promoted the growth and migration of NSCLC cells. Using bioinformatics analysis, we identified downregulated PP2Ac expression in NSCLC cells upon treatment with MCM. We further confirmed that this downregulation was executed in an NF‐κB pathway‐dependent manner. As IκB kinase (IKK) has been proved to be a substrate of PP2Ac, inhibition on PP2Ac could result in amplification of NF‐κB pathway signaling. Overexpression of PP2Ac, or the dominant‐negative forms of IKK or IκB, attenuated the acceleration of growth and metastasis by MCM. Using bioinformatics analysis, we further identified that CXCL1 and COL6A1 could be downstream of NF‐κB/PP2Ac pathway. Luciferase assay and ChIP assay further confirmed the location of response elements on the promoter regions of CXCL1 and COL6A1. Elevated CXCL1 facilitated angiogenesis, whereas upregulated COL6A1 promoted proliferation and migration.
Tumor‐associated macrophages, the prominent type of inflammatory cells in non‐small‐cell lung cancer, can promote the growth and metastasis of cancer cells. Overexpression of PP2Ac, or the dominant‐negative forms of IKK or IκB, attenuated the acceleration on cancer cell growth and metastasis by TAMs. CXCL1 and COL6A1 could be downstream of NF‐κB/PP2Ac pathway. Elevated CXCL1 facilitated angiogenesis, whereas upregulated COL6A1 promoted cancer cell proliferation and migration.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Copper-catalyzed synthesis of 2-arylquinazolin-4-amines from readily available 2-arylindoles and TMSN3 has been developed. The mechanism study shows that the domino reaction may involve a free ...radical diazidation, denitrogenation, intramolecular cyclization and ring expansion sequence.
Herein, we show that the combination of the Birch reduction of readily available anisole derivatives and the catalytic asymmetric inverse‐electron‐demand Diels–Alder reaction of 2‐pyrones can serve ...as a powerful platform for the diverse synthesis of synthetically important cis‐decalin scaffolds. Enabled by a well‐modified chiral bis(oxazoline) ligand/CuII complex, a wide range of polysubstituted cis‐decalin scaffolds with up to six contiguous stereocenters were generated efficiently. The synthetic potential of this method is demonstrated by the concise synthesis of the sesquiterpene (+)‐occidentalol and a key intermediate for seven triterpenes. Mechanistic studies suggest the 1,3‐cyclohexadienes formed in situ are the key intermediates, and efficient kinetic resolution occurs when C2‐ and/or C3‐substituted 1,4‐cyclohexadienes are utilized as substrates. DFT calculations elucidated that the Diels–Alder reaction proceeds in a stepwise fashion and revealed the origins of the stereoselectivities.
Asymmetric synthesis of highly functionalized chiral cis‐decalins was realized by merging Birch reduction and a tandem olefin migration/asymmetric IEDDA reaction. Up to six contiguous and two quaternary stereocenters could be formed in one step by efficient kinetic resolution. The synthetic value of the approach is illustrated by the concise total synthesis of (+)‐occidentalol and the synthesis of a key intermediate for seven triterpenes.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
An enantioselective chemical synthesis of arene cis‐dihydrodiols has been realized from 2‐pyrones through sequential ytterbium‐catalyzed asymmetric inverse‐electron‐demand Diels–Alder (IEDDA) ...reaction of 2‐pyrones and retro‐Diels–Alder extrusion of CO2. By using this strategy, a series of substituted arene cis‐dihydrodiols can be obtained efficiently with high enantioselectivity (>99 % ee in many cases). Based on this strategy, efficient and concise asymmetric total syntheses of (+)‐MK7607 and 1‐epi‐(+)‐MK7607 were accomplished.
An enantioselective chemical synthesis of arene cis‐dihydrodiols from 2‐pyrones through sequential ytterbium‐catalyzed asymmetric inverse‐electron‐demand Diels–Alder (IEDDA) reaction of 2‐pyrones and retro‐Diels–Alder extrusion of CO2 is reported. This method provides a powerful chemical method for the enatioselective synthesis of arene cis‐dihydrodiols as a reliable alternative to traditional enzymatic catalysis.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Pesticides directly pollute the environment and contaminate foods ultimately being absorbed by the human body. Their residues contain highly toxic substances that have been found to cause serious ...problems to human health even at very low concentrations. The gold standard method, gas/liquid chromatography combined with mass spectroscopy, has been widely used for the detection of pesticide residues. However, these methods have some drawbacks such as complicated pretreatment and cleanup steps. Recent technological advancements of surface-enhanced Raman spectroscopy (SERS) have promoted the creation of alternative detection techniques. SERS is a useful detection tool with ultrasensitivity and simpler protocols. Present SERS-based pesticide residue detection often uses standard solutions of target analytes in conjunction with theoretical Raman spectra calculated by density functional theory (DFT) and actual Raman spectra detected by SERS. SERS is quite a promising technique for the direct detection of pesticides at trace levels in liquid samples or on the surface of solid samples following simple extraction to increase the concentration of analytes. In this review, we highlight recent studies on SERS-based pesticide detection, including SERS for pesticide standard solution detection and for pesticides in/on food samples. Moreover, in-depth analysis of pesticide chemical structures, structural alteration during food processing, interaction with SERS substrates, and selection of SERS-active substrates is involved.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM, UPUK
In the past few decades, palladium-catalyzed cross-coupling reactions have taken root in the construction of a complex synthetic community. The development of organometallics has been an important ...objective in this field. Our group has focused on exploiting new germanium-based reagents and the corresponding catalytic processes. In the past three years, we have established new methods for the synthesis of structure-modified (hetero)aryl germatranes and alkyl carbagermatranes. Particularly for alkyl carbagermatranes, the stability to be compatible with various derivatization reactions and the high activity for transmetallation (
e.g.
base/additive-free for primary alkyl carbagermatranes) distinguish them from many reported nucleophiles. In this article, we would introduce (1) the development process of organogermanium reagents in palladium-catalyzed cross-couplings; (2) the history of germatrane-type systems and the breakthrough we have made in the field; (3) the outlook for (carba)germatranes and alkyl-GeMe
3
.
The synthesis and Pd-catalyzed cross-couplings of structure-modified (hetero)aryl germatranes and alkyl carbagermatranes have been established.
The first catalytic enantioselective construction of biologically important tetrahydroquinolin-5-one-based spirooxindole has been developed via a chiral cinchona alkaloid catalyzed asymmetric ...three-component 3 + 3 cyclization of cyclic enaminone, isatin, and malononitrile, which afforded a series of tetrahydroquinolin-5-one-based spirooxindoles in high yields and with excellent enantioselectivities (up to 99% yield, 97:3 er). This reaction could be applicable to large-scale synthesis of enantioenriched tetrahydroquinolin-5-one-based spirooxindoles. This synthetic methodology will not only provide a unique approach for the construction of chiral tetrahydroquinolin-5-one-based spirooxindole scaffolds but also increase our understanding of catalytic enantioselective multicomponent reactions.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
PDF
