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The 3‐selenocyanato‐substituted indoles were readily synthesized via (dichloroiodo)benzene (PhICl2)‐induced reaction of 2‐alkynylanilines or 2‐alkenylanilines with KSeCN in MeCN under metal‐free conditions. The reaction sequence was postulated to encompass the formation of a reactive selenocyanogen chloride species, generated in situ from the reaction of PhICl2 and KseCN, followed by electrophilic addition and intramolecular cyclization steps. [ABSTRACT FROM AUTHOR]

The isothermal enzyme‐free nucleic acid amplification method plays an indispensable role in biosensing by virtue of its simple, robust, and highly efficient properties without the assistance of temperature cycling or/and enzymatic biocatalysis. Up to now, enzyme‐free nucleic acid amplification has been extensively utilized for biological assays and has achieved the highly sensitive detection of various biological targets, including DNAs, RNAs, small molecules, proteins, and even cells. In this Review, the mechanisms of entropy‐driven reaction, hybridization chain reaction, catalytic hairpin assembly and DNAzyme are concisely described and their recent application as biosensors is comprehensively summarized. Furthermore, the current problems and the developments of these DNA circuits are also discussed. [ABSTRACT FROM AUTHOR]

The selective synthesis of 3‐halogenated quinolin‐2‐ones from N‐arylpropynamides was realized via umpolung process mediated by phenyliodine(III) diacetate (PIDA) and MX (LiCl, LiBr, CuI). Differing from most previous electrophilic cyclization/halogenation processes that afforded spiro[4,5]trienones, 3‐halogenated quinolin‐2‐ones were obtained through this method with high selectivity. [ABSTRACT FROM AUTHOR]

Based on surface plasmon resonance (SPR), a novel refractive index (RI) sensor comprising a square photonic crystal fiber (PCF) is proposed to realize the detection of the annular analyte. Instead of hexagon structure, four large air-holes in a square array are introduced to enhance the sensitivity by allowing two polarization directions of the core mode to be more sensitive. The gold is used as the only plasmonic material. The design purpose is to reduce the difficulty in gold deposition and enhance the RI sensitivity. The guiding properties and the effects of the parameters on the performance of the sensor are numerically investigated by the Finite Element Method (FEM). By optimizing the structure, the sensor can exhibit remarkable sensitivity up to 7250 nm/RIU and resolution of RIU with only one plasmonic material, which is very competitive compared with the other reported externally coated and single-layer coated PCF-based SPR (PCF-SPR) sensors, to our best knowledge. [ABSTRACT FROM AUTHOR]