Visible‐Light‐Induced Trifluoromethylation of Isonitrile‐Substituted Methylenecyclopropanes: Facile Access to 6‐(Trifluoromethyl)‐7,8‐Dihydrobenzo[k]phenanthridine Derivatives

A new visible‐light‐induced trifluoromethylation of isonitrile‐substituted methylenecyclopropanes is developed. A range of substituted 6‐(trifluoromethyl)‐7,8‐dihydrobenzo[k]phenanthridine derivatives are readily furnished by this newly developed tandem reaction with moderate to good yields. This reaction allows the direct formation of two six‐membered rings and three new C?C bonds, including the C?CF₃ bond, under visible light irradiation.     

Copper Causes Regiospecific Formation of C4F8‐Containing Six‐Membered Rings and their Defluorination/Aromatization to C4F4‐Containing Rings in Triphenylene/1,4‐C4F8I2 Reactions

The presence of Cu in reactions of triphenylene (TRPH) and 1,4‐C₄F₈I₂ at 360 °C led to regiospecific substitution of TRPH ortho C(β) atoms to form C₄F₈‐containing rings, completely suppressing substitution on C(α) atoms. In addition, Cu caused selective reductive‐defluorination/aromatization (RD/A) to form C₄F₄‐containing aromatic rings. Without Cu, the reactions of TRPH and 1,4‐C₄F₈I₂ were not regiospecific and no RD/A was observed. These results, supported by DFT calculations, are the first examples of Cu‐promoted 1) regiospecific perfluoroannulation, 2) preparative C?F activation, and 3) RD/A. HPLC‐purified products were characterized by X‐ray diffraction, low‐temperature PES, and ¹H/¹⁹F NMR.     

Regioselective Alkylative Carboxylation of Allenamides with Carbon Dioxide and Dialkylzinc Reagents Catalyzed by an N‐Heterocyclic Carbene–Copper Complex

The alkylative carboxylation of allenamide catalyzed by an N‐heterocyclic carbene (NHC)–copper(I) complex [(IPr)CuCl] with CO₂ and dialkylzinc reagents was investigated. The reaction of allenamides with dialkylzinc reagents (1.5 equiv) and CO₂ (1 atm.) proceeded smoothly in the presence of a catalytic quantity of [(IPr)CuCl] to afford (Z)‐α,β‐dehydro‐β‐amino acid esters in good yields. The reaction is regioselective, with the alkyl group introduced onto the less hindered γ‐carbon, and the carboxyl group introduced onto the β‐carbon atom of the allenamides. The first step of the reaction was alkylative zincation of the allenamides to give an alkenylzinc intermediate followed by nucleophilic addition to CO₂. A variety of cyclic and acyclic allenamides were found to be applicable to this transformation. Dialkylzinc reagents bearing β‐hydrogen atoms, such as Et₂Zn or Bu₂Zn, also gave the corresponding alkylative carboxylation products without β‐hydride elimination. The present methodology provides an easy route to alkyl‐substituted α,β‐dehydro‐β‐amino acid ester derivatives under mild reaction conditions with high regio‐ and stereoselectivtiy.     

A Magnetic Nanoparticle-Based Time-Resolved Fluoroimmunoassay for Determination of the Cytokeratin 19 Fragment in Human Serum

A sensitive, rapid and novel measurement method for cytokeratin 19 fragment (CYFRA 21–1) in human serum by magnetic particle-based time-resolved fluoroimmunoassay (TRFIA) is described. Built on a sandwich-type immunoassay format, analytes in samples were captured by one monoclonal antibody coating onto the surface of magnetic beads and “sandwiched” by another monoclonal antibody labeled with europium chelates. The coefficient variations of the method were lower than 7 %, and the recoveries were in the range of 90–110 % for serum samples. The lower limit of quantitation of the present method for CYFRA 21–1 was 0.78 ng/ml. The correlation coefficient of CYFRA 21–1 values obtained by our novel TRFIA and CLIA was 0.980. The present novel TRFIA demonstrated high sensitivity, wider effective detection range and excellent reproducibility for determination of CYFRA 21–1 can be useful for early screening and prognosis evaluation of patients with non-small cell lung cancer.     

Catalytic carbon dioxide hydrogenation to methane: A review of recent studies

Recently,various efforts have been put forward on the development of technologies for the synthesis of methane from CO₂ and H₂,since it can offer a solution for renewable H₂ storage and transportation.In parallel,this reaction is considered to be a critical step in reclaiming oxygen within a closed cycle.Over the years,extensive fundamental research works on CO₂ methanation have been investigated and reported in the literatures.In this updated review,we present a comprehensive overview of recent publications during the last 3 years.Various aspects on this reaction system are described in detail,such as thermodynamic considerations,catalyst innovations,the influence of reaction conditions,overall catalytic performance,and reaction mechanism.Finally,the future development of CO₂ methanation is discussed.     

Generic applications of 13C‐detected NMR diffusion to formulated systems with suppression of thermal convection induced by proton decoupling

Fast and effective structural/compositional analysis on formulated systems represents one of the major challenges encountered in analytical science. ¹³C‐detected diffusion represents a promising tool to tackle the aforementioned challenges, particularly in industry. Toward exploring the generic applications of ¹³C‐detected diffusion, thermal convection induced by ¹H decoupling has been identified as a key factor that resulted in significantly reduced resolution in the diffusion dimension. Optimization of experimental parameters and utilization of double‐stimulated echo‐based pulse sequence both can effectively suppress the thermal convection caused by the ¹H decoupling, the success of which allows robust and generic applications of ¹³C‐detected diffusion to systems from mixtures of small molecules, polymer blends, and copolymers to actual complex formulated systems. The method is particularly powerful in differentiating small molecules from polymers, polymer blends from copolymers, and end‐group analysis. Copyright © 2016 John Wiley & Sons, Ltd.