Pd-Catalyzed Cascade Cyclization/Thiocarbonylation with Thioformates: Synthesis of Thioester-Functionalized Oxindoles.

A Pd-catalyzed thiocarbonylative cyclization of N-(o-iodoaryl)acrylamides with easily accessible thioformates has been developed. The reaction has a wide substrate scope with good yields and represents a powerful route to the synthesis of thioester-functionalized oxindoles. Both S-aryl and alkyl thioformates as the thioester sources were well tolerated. The active Pd-CO intermediate may play an important role in the transformation process.

Palladium-catalyzed cascade cyclization of α,ß-unsaturated N-tosylhydrazones with iodoarenes: access to 2H-chromenes and 2H-quinolines.

A palladium-catalyzed cascade reaction of α,ß-unsaturated N-tosylhydrazones with iodoarene derivatives containing a nucleophilic group has been developed, which provides facile access to 2H-chromenes and 2H-quinolines, respectively. Additionally, the double Pd-carbene migratory insertion/nucleophilic substitution processes for the synthesis of a ternary heterocyclic skeleton were possible in the developed catalytic system.

Palladium-Catalyzed Heck Cyclization with P(O)H Compounds to Construct Phosphinonyl-Azaindoline and -Azaoxindole Derivatives.

We report herein a concise method for the construction of phosphinonyl-azaindoline and -azaoxindole derivatives via a palladium-catalyzed cascade cyclization with P(O)H compounds. Various H-phosphonates, H-phosphinates, and aromatic secondary phosphine oxides are all tolerated under the reaction conditions. Furthermore, the phosphinonyl-azaindoline isomer families such as 7-, 5-, and 4-azaindolines could be synthesized in moderate to good yields.

Bipolar Switching Properties of the Transparent Indium Tin Oxide Thin Film Resistance Random Access Memories.

In this study, the bipolar switching properties and electrical conduction behaviors of the ITO thin films RRAM devices were investigated. For the transparent RRAM devices structure, indium tin oxide thin films were deposited by using the RF magnetron sputtering method on the ITO/glass substrate. For the ITO/ITOX/ITO/glass (MIM) structure, an indium tin oxide thin film top electrode was prepared to form the transparent RRAM devices. From the experimental results, the 102 On/Off memory ratio and bipolar switching cycling properties for set/reset stable states were found and discussed. All transparent RRAM devices exhibited the obvious memory window and low set voltage for the switching times of 120 cycles. The electrical transport mechanisms were dominated by the ohmic contact and space charge limit conduction (SCLC) models for set and reset states. Finally, the transmittances properties of the transparent ITO/ITOX/ITO RRAM devices for the different oxygen growth procedures were about 90% according to the UV-Vis spectrophotometer for the visible wavelength range.

Palladium-Catalyzed Allylation of P(O)H Compounds: Access to 2-Fluoroallylic Phosphorus Compounds.

An efficient palladium-catalyzed 2-fluoroallylation of P(O)H compounds with gem-difluorocyclopropanes is presented. The reaction provides a variety of 2-fluoroallylic phosphorus compounds in good yields with high Z selectivity through the sequential C-C bond activation, C-F bond cleavage, and C-P coupling process. Various H-phosphonates, H-phosphinates, and secondary phosphine oxides are all tolerated. In addition, the gram-scale synthesis and the late-stage modification of complex bioactive molecules show practical utilities of the transformation.

Highly regioselective and stereoselective cascade reductive cyclization of δ-ketoamide: practical access to oxa-bridged benzazepines.

A highly regioselective and stereoselective cascade reduction cyclization of δ-ketoamide is realized under LiAlH4-assisted conditions, providing an atom-economical and straightforward approach to access oxa-bridged benzazepines in moderate to good yields. This method overcomes the limitations of aldehydes or other precursors of primary alcohols and realizes the cascade reduction cyclization of secondary alcohol anions generated in situ from ketones. The reaction proceeds with broad substrate scope and good functional group compatibility.

Lipidomic Analysis of Caenorhabditis elegans Embryos.

Metabolomic is an emerging field of system biology. Lipidomic, a branch of metabolomic, aims to characterize lipophilic metabolites in biological systems. Caenorhabditis elegans (C. elegans) is a genetically tractable and versatile animal model for novel discovery of lipid metabolism. In addition, C. elegans embryo is simple and homogeneous. Here, we demonstrate detailed procedures of C. elegans culture, embryo isolation, lipid extraction and metabolomic data analysis.

Impaired embryonic development in glucose-6-phosphate dehydrogenase-deficient Caenorhabditis elegans due to abnormal redox homeostasis induced activation of calcium-independent phospholipase and alteration of glycerophospholipid metabolism.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a commonly pervasive inherited disease in many parts of the world. The complete lack of G6PD activity in a mouse model causes embryonic lethality. The G6PD-deficient Caenorhabditis elegans model also shows embryonic death as indicated by a severe hatching defect. Although increased oxidative stress has been implicated in both cases as the underlying cause, the exact mechanism has not been clearly delineated. In this study with C. elegans, membrane-associated defects, including enhanced permeability, defective polarity and cytokinesis, were found in G6PD-deficient embryos. The membrane-associated abnormalities were accompanied by impaired eggshell structure as evidenced by a transmission electron microscopic study. Such loss of membrane structural integrity was associated with abnormal lipid composition as lipidomic analysis revealed that lysoglycerophospholipids were significantly increased in G6PD-deficient embryos. Abnormal glycerophospholipid metabolism leading to defective embryonic development could be attributed to the increased activity of calcium-independent phospholipase A2 (iPLA) in G6PD-deficient embryos. This notion is further supported by the fact that the suppression of multiple iPLAs by genetic manipulation partially rescued the embryonic defects in G6PD-deficient embryos. In addition, G6PD deficiency induced disruption of redox balance as manifested by diminished NADPH and elevated lipid peroxidation in embryos. Taken together, disrupted lipid metabolism due to abnormal redox homeostasis is a major factor contributing to abnormal embryonic development in G6PD-deficient C. elegans.