Cooperative Tertiary Amine/Palladium-Catalyzed Sequential [4 + 3] Cyclization/[1,3]-Rearrangement for Stereoselective Synthesis of Spiro [Methylenecyclopentane-1,3'-oxindolines].

A cooperative tertiary amine/palladium-catalyzed sequential reaction process, proceeding via a [4 + 3] cyclization of isatin-derived Morita-Baylis-Hillman Expansion (MBH) carbonates and tert-butyl 2-(hydroxymethyl)allyl carbonates followed by a [1,3]-rearrangement, has been found and developed. A range of structurally diverse spiro[methylene cyclopentane-1,3'-oxindolines] bearing two adjacent ß,γ-acyl quaternary carbon stereocenters, which are difficult to obtain by conventional strategies, were obtained in good yields. Further synthetic utility of this protocol is highlighted by its excellent regio- and stereocontrol as well as the large-scale synthesis and diverse functional transformations of the synthetic compounds. Moreover, the control experiments probably established the plausible mechanism for this sequential [4 + 3] cyclization/[1,3]-rearrangement process.

2,2'-Bipyridine-Enabled Photocatalytic Radical [4+2] Cyclization of N-Aryl-α-amino Acids for Synthesizing Polysubstituted Tetrahydroquinolines.

A facile photocatalytic radical [4+2] cyclization of N-aryl-α-amino acids with various alkenes to access structurally polysubstituted tetrahydroquinolines has been developed. Using a simple bipyridine as a catalyst, different N-aryl-α-amino acids could be utilized as the radical precursors to react with diverse electrophilic alkenes, including exocyclic terminal alkenes, acyclic terminal alkenes, and cycloalkenes, producing 10 types of nitrogen-containing heterocyclic compounds fused in multiple frameworks in generally moderate yields with good diastereoselectivities. Scale-up synthesis and transformations of the products further demonstrated the synthetic application of this protocol. Moreover, a decarboxylative radial pathway via a proton-coupled electron transfer process for illustration of this [4+2] cyclization was proposed on the basis of the control experiments. This process is highlighted by a simple bipyridine photocatalysis, mild reaction conditions, various N-aryl-α-amino acids and alkene materials, and application for the modification of natural products.

Iron(II)-Catalyzed Radical [3 + 2] Cyclization of N-Aryl Cyclopropylamines for the Synthesis of Polyfunctionalized Cyclopentylamines.

A facile iron(II)-catalyzed radical [3 + 2] cyclization of N-aryl cyclopropylamines with various alkenes to access the structurally polyfunctionalized cyclopentylamine scaffolds has been developed. Using low-cost FeCl2·4H2O as catalyst, N-aryl cyclopropylamines could be utilized to react with a wide range of alkenes including exocyclic/acyclic terminal alkenes, cycloalkenes, alkenes from the natural-occurring compounds (Alantolactone, Costunolide), and known drugs (Ibuprofen, l-phenylalanine, Flurbiprofen) to obtain a variety of cyclopentylamines fused with different useful motifs in generally good yields and diastereoselectivities. The highlight of this protocol is also featured by no extra oxidant, no base, EtOH as the solvent, gram-scale synthesis, and further diverse transformations of the synthetic products. More importantly, an iron(II)-mediated hydrogen radical dissociation pathway was proposed based on the mechanism research experiments.

Copper Induces Spleen Damage Through Modulation of Oxidative Stress, Apoptosis, DNA Damage, and Inflammation.

Copper (Cu) is an essential micronutrient for both humans and animals; however, excessive intake of Cu can be immunotoxic. There are limited studies on spleen toxicity induced by Cu. This study was conducted to investigate the effects of Cu on spleen oxidative stress, apoptosis, and inflammatory responses in mice orally administered with 0 mg/kg, 10 mg/kg, 20 mg/kg, and 40 mg/kg of CuSO4 for 42 days. As discovered in this work, copper sulfate (CuSO4) reduced the activities of antioxidant enzymes (SOD, CAT, and GSH-Px), decreased GSH contents, and increased MDA contents. Meanwhile, CuSO4 induced apoptosis by increasing TUNEL-positive cells in the spleen. Also, CuSO4 increased the expression of γ-H2AX, which is the marker of DNA damage. Concurrently, CuSO4 caused inflammation by increasing the mRNA levels of interleukin-1ß (IL-1ß), IL-2, IL-4, IL-6, IL-12, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ). In conclusion, the abovementioned findings demonstrate that over 10 mg/kg CuSO4 can cause oxidative stress, apoptosis, DNA damage, and inflammatory responses, which contribute to spleen dysfunction in mice.

Research on the evaluation of the resilience of subway station projects to waterlogging disasters based on the projection pursuit model.

To improve sustainable development, increasingly more attention has been paid to the evaluation of the resilience to waterlogging disasters. This paper proposed a projection pursuit model (PPM) improved by quantum particle swarm optimization (QPSO) for the evaluation of the resilience of subway station projects to waterlogging disasters. In view of the lack of research results related to the evaluation of the resilience of subway station projects to waterlogging disasters, 16 secondary indicators that affected the ability of subway station projects to recover from waterlogging disasters were identified from defense, recovery, and adaptability, for the first time. A PPM improved by QPSO was then proposed to effectively deal with the high-dimensional data about the resilience of subway station projects to waterlogging disasters. The QPSO was used to solve the best projection vector of the PPM, and interpolation algorithm was used to construct the mathematical model of evaluation. Finally, four station projects of Chengdu Metro Line 11 in China were selected for a case study analysis. The case study revealed that, among the secondary indicators, the emergency plan of construction order, the exercise frequency of emergency plans, and relief supplies had the greatest weights. The recovery was found to be the most important in the primary indicators. The values of the resilience of Lushan Avenue Station, Miaoeryan Station, Shenyang Road Station, and Tianfu CBD North Station to waterlogging disasters were found to be 2, 1.6571, 2.8318, and 3 respectively. This resilience ranking was consistent with the actual disaster situation in the flood season of 2019. In addition, the case study results showed that QPSO had the advantages of fewer parameter settings and a faster convergence speed as compared with PSO and the genetic algorithm.