Copper-Catalyzed Aryne Insertion into the Carbon-Iodine Bond of Heteroaryl Iodides.

Aryne insertions into the carbon-iodine bond of heteroaryl iodides has been achieved for the first time. This novel reaction provides an efficient pathway for the synthesis of valuable building blocks 2-iodoheterobiaryls from heteroaryl iodides and o-silylaryl triflates in excellent regioselectivity. The copper(I) catalyst, which bears a N-heterocyclic carbene (NHC) ligand, is essential to accomplish the reaction. Control reactions and DFT calculations indicate that the coordination of copper, as a Lewis acid, with nitrogen atoms of heteroaryl iodides mediates the insertion of arynes into heteroaryl carbon-iodine bonds.

The combination of sesamol and clofibric acid moieties leads to a novel potent hypolipidemic agent with antioxidant, anti-inflammatory and hepatoprotective activity.

Oxidative stress and inflammation have been considered the main factors in the liver injury of clofibrate (CF). To obtain a novel antihyperlipidemic agent with antioxidant, anti-inflammation and hepatoprotection, the combination of sesamol and clofibric acid moieties was performed and achieved sesamol-clofibrate (CF-Sesamol). CF-Sesamol showed significant hypolipidemia effects in hyperlipidemia mice induced by Triton WR 1339, reducing TG by 38.8% (P < 0.01) and TC by 35.1% (P < 0.01). CF-Sesamol also displayed an alleviating effect on hepatotoxicity. The hepatic weight and hepatic coefficient were decreased. The amelioration of liver function was observed, such as aspartate and lactate transaminases (AST and ALT), alkaline phosphatase (ALP) and total proteins (TP) levels. Liver histopathological examination showed that hepatocyte necrosis, cytoplasmic loosening, nuclear degeneration and inflammatory cell infiltration reduced obviously by treatment with CF-Sesamol. Related molecular mechanisms on hepatoprotection showed that CF-Sesamol up-regulated Nrf2 and HO-1 expression and down-regulated p-NF-κB p65 expression in hepatic tissues. CF-Sesamol has significant antioxidant and anti-inflammatory effects. Plasma antioxidant enzymes such as SOD and CAT increased, anti-lipid peroxidation product MDA decreased. The expression of TNF-α and IL-6 inflammatory cytokines in liver was significantly lower than that in the CF group. The results indicated that CF-Sesamol exerted more potent antihyperlipidemic effects and definite hepatoprotective activity partly through the Nrf2/NF-κB-mediated signaling pathway.

Airport Exposure to Lightning Strike Hazard in the Contiguous United States.

Reliability of the air transportation system heavily depends on the performance of communication, navigation, and surveillance facilities in the National Airspace System (NAS). These facilities are prone to outages caused by convective weather, such as lightning. Current lightning safety standards and risk assessments focus solely on lightning occurrence and omit the effect of lightning intensity from hazard characterization. We propose methods that incorporate lightning intensity and occurrence parameters to better understand the impact of lightning strike on the NAS using the National Lightning Detection Network and Federal Aviation Administration NAS facilities and equipment outage databases. Spatial analysis and clustering reveal different exposure profiles for 436 U.S. airports. Kernel Density estimation and Hot Spot analysis show that regardless of lightning intensity, Southern state airports are the most exposed to lightning hazards. K-means clustering reveal five different lightning exposure profiles that mimic the spatial patterns produced by the Kernel Density estimation and Hot Spot analysis. A scoring system ranks all airports according to their exposure profile taking into consideration lightning occurrence and intensity. It is complemented with a rising trend exposure analysis, which identifies airports whose exposure could be underestimated under the current standards, identifying airports with fewer lightning occurrences but higher intensities. Finally, a comparison between the exposure patterns and lightning-induced outages provide insights into U.S. lightning impact patterns. Similar patterns between lightning exposure and outages indicate that the results of the proposed lightning hazard assessment provide useful information for prioritizing airport hardening investments at the national scale and reducing lightning risk.

Access to functionalized 3H-pyrrolo[2,3-c]quinolin-4(5H)-ones and thieno[2,3-c]quinolin-4(5H)-ones via domino reaction of 4-alkynyl-3-bromoquinolin-2(1H)-ones.

We describe two efficient protocols for the straightforward synthesis of 3H-pyrrolo[2,3-c]quinolin-4(5H)-one and thieno[2,3-c]quinolin-4(5H)-one derivatives from readily available 4-alkynyl-3-bromoquinolin-2(1H)-one as precursor. The efficient synthesis of highly functionalized 3H-pyrrolo[2,3-c]quinolin-4(5H)-ones has been achieved via a palladium-catalyzed domino reaction of 4-alkynyl-3-bromoquinolin-2(1H)-ones with amines. Thieno[2,3-c]quinolin-4(5H)-one derivatives were also conveniently synthesized via sequential nucleophilic aromatic substitution/5-endo-dig cyclization between 4-alkynyl-3-bromoquinolin-2(1H)-ones and sodium sulfide with good functional tolerance under mild conditions.

Superconducting dome associated with the suppression and re-emergence of charge density wave states upon sulfur substitution in CuIr2Te4chalcogenides.

We report the path from the charge density wave (CDW)-bearing superconductor CuIr2Te4to the metal insulator transition (MIT)-bearing compound CuIr2S4by chemical alloying with the gradual substitution of S for Te. The evolution of structural and physical properties of the CuIr2Te4-xSx(0 ⩽x⩽ 4) polycrystalline system is systemically examined. The x-ray diffraction (XRD) results imply CuIr2Te4-xSx(0 ⩽x⩽ 0.5) crystallizes in a NiAs defected trigonal structure, whereas it adapts to the cubic spinel structure for 3.6 ⩽x⩽ 4 and it is a mixed phase in the doping range of 0.5

Interplay between Charge-Density-Wave, Superconductivity, and Ferromagnetism in CuIr2-xCrxTe4 Chalcogenides.

We report the crystal structure, charge-density-wave (CDW), superconductivity (SC), and ferromagnetism (FM) in CuIr2-xCrxTe4 (0 ≤ x ≤ 2) chalcogenides. Powder x-ray diffraction (PXRD) results reveal that the CuIr2-xCrxTe4 series are distinguished between two structural types and three different regions: (i) layered trigonal structure region, (ii) mixed phase regions, and (iii) spinel structure region. Besides, Cr substitution for Ir site results in rich physical properties including the collapse of CDW, the formation of dome-shaped like SC, and the emergence of magnetism. Cr doping slightly elevates the superconducting critical temperature (Tsc) to its highest Tsc = 2.9 K around x = 0.06. As x increases from 0.3 to 0.4, the ferromagnetic Curie temperature (Tc) increases from 175 to 260 K. However, the Tc remains unchanged in the spinel range of 1.9 ≤ x ≤ 2. This finding provides a comprehensive material platform for investigating the interplay between CDW, SC, and FM multipartite quantum states.

Antimicrobial Terpenes Suppressed the Infection Process of Phytophthora in Fennel-Pepper Intercropping System.

The interactions between non-host roots and pathogens may be key to the inhibition of soilborne pathogens in intercropping systems. Fennel (Foeniculum vulgare) can be intercropped with a wide range of other plants to inhibit soilborne pathogens in biodiversity cultivation. However, the key compounds of fennel root exudates involved in the interactions between fennel roots and pathogens are still unknown. Here, a greenhouse experiment confirmed that intercropping with fennel suppressed pepper (Capsicum annuum) blight disease caused by Phytophthora capsici. Experimentally, the roots and root exudates of fennel can effectively interfere with the infection process of P. capsici at rhizosphere soil concentrations by attracting zoospores and inhibiting the motility of the zoospores and germination of the cystospores. Five terpene compounds (D-limonene, estragole, anethole, gamma-terpenes, and beta-myrcene) that were identified in the fennel rhizosphere soil and root exudates were found to interfere with P. capsica infection. D-limonene was associated with positive chemotaxis with zoospores, and a mixture of the five terpene compounds showed a strong synergistic effect on the infection process of P. capsici, especially for zoospore rupture. Furthermore, the five terpene compounds can induce the accumulation of reactive oxygen species (ROS), especially anethole, in hyphae. ROS accumulation may be one of the antimicrobial mechanisms of terpene compounds. Above all, we proposed that terpene compounds secreted from fennel root play a key role in Phytophthora disease suppression in this intercropping system.

Expeditious Synthesis of Isoquinolone Derivatives by Rhodium(I)-Catalyzed Annulation Reaction through C-C Bond Cleavage.

A Rh(I)-catalyzed intermolecular cyclization between isocyanates and benzocyclobutenols leading to isoquinolin-1(2 H)-ones through selective cleavage of a C-C bond has been realized. Exploiting the same strategy, we developed a Rh(I)-catalyzed three-component reaction of benzocyclobutenols, isonitriles, and sulfonyl azides to access isoquinolin-1(2 H)-imines. These procedures provide unique and expeditious access to isoquinolone derivatives which are otherwise difficult to prepare in satisfactory yields with excellent functional-group tolerance under mild reaction conditions.