Cation‐binding salen nickel catalysts were developed for the enantioselective alkynylation of trifluoromethyl ketones in high yield (up to 99 %) and high enantioselectivity (up to 97 % ee). The reaction proceeds with substoichiometric quantities of base (10–20 mol % KOt‐Bu) and open to air. In the case of trifluoromethyl vinyl ketones, excellent chemo‐selectivity was observed, generating 1,2‐addition products exclusively over 1,4‐addition products. UV‐vis analysis revealed the pendant oligo‐ether group of the catalyst strongly binds to the potassium cation (K+) with 1:1 binding stoichiometry (Ka=6.6×105 m−1).

The level of human serum albumin (HSA) in biological fluids is a key health indicator and its quantitative determination has great clinical importance. In this study, we developed a selective and sensitive fluorescent HSA probe by fluorescence-based high-throughput screening of a set of fluorescent thieno[3,2-b]pyridine-5(4H)-one derivatives against major plasma proteins: HSA, bovine serum albumin (BSA), globulin, fibrinogen, and transferrin. The fluorophore chosen finally (4) showed noticeable fluorescence enhancement in the presence of HSA (160-fold increase), and it exhibited rapid response, high sensitivity (detection limit 8 nM), and the ability to clearly distinguish HSA from BSA in pH 9 buffer condition. Moreover, the probe could be applicable to detect trace amounts of HSA in an artificial urine sample; further, it might be applied to the determination of the HSA concentration in complex biological samples for pre-clinical diagnosis.

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In this study, we report a direct fluorometric assay for butyrylcholinesterase (BChE) activity and screening of its inhibitor, using a fluorescent substrate. 2-(2-(5,6-Dimethoxy-1,3-dioxoisoindolin-2-yl)acetoxy)-N,N,N-trimethylethan-1-ammonium iodide (1) was hydrolyzed by BChE, and its fluorescence was quenched by an intramolecular photoinduced electron transfer process. The resulting change in fluorescence provided a facile method for real-time BChE activity testing. Remarkably, 1 was selectively hydrolyzed by BChE, even in the presence of excess acetylcholinesterase, thereby facilitating the specific monitoring of BChE activity. This assay method is also useful for screening potential BChE inhibitors. Given its simplicity, selectivity, and higher assay speed, this method may be extended to high-throughput screening of BChE inhibitors and relevant drug discovery.