A mild and efficient synthesis of N-arylcarbamates was achieved by reacting azidoformates with boronic acids in the presence of 10 mol % of copper chloride catalyst. The reaction proceeds readily in an open flask at room temperature without additional base, ligand, or additive. Rapid access to urea analogues via a two-step one-pot procedure is enabled by reacting N-arylcarbamates with aluminum-amine complexes. In addition, among several boronic acid derivatives prepared, dimethylphenyl boronate was found to react rapidly in its reaction with benzyl azidoformate, invoking in situ generation of this species in the catalytic cycle.

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.

Fluorescent probes are attractive tools for biology, drug discovery, disease diagnosis, and environmental analysis. In bioimaging, these easy-to-operate and inexpensive probes can be used to detect biological substances, obtain detailed...

We describe a synthetic approach for a set of fluorescent thieno­[3,2-b]­pyridine-5­(4H)-one derivatives and their photophysical properties. These fluorophores are prepared by a series of reactions employing the Suzuki–Miyaura cross-coupling reaction and a regioselective aza-[3 + 3] cycloaddition of 3-aminothiophenes with α,β-unsaturated carboxylic acids. Our findings revealed that the photophysical properties are chemically tunable by an appropriate choice of functional group on the thieno­[3,2-b]­pyridine-5­(4H)-one scaffold.

A fluorescent probe (4-(2-(4-(diethylamino)phenyl)-4-methyl-5-oxo-4,5-dihydrothieno[3,2- b ]pyridin-7-yl)phenyl 2,4-dinitrobenzenesulfonate, KF-DNBS ) for facile detection of H 2 S in serum was developed based on the combination of an environment-sensitive fluorophore (2-(4-(diethylamino)phenyl)-7-(4-hydroxyphenyl)-4-methylthieno[3,2- b ]pyridin-5(4 H )-one, KF ) with albumin and the 2,4-dinitrobenzene sulfonyl (DNBS) group as a recognition unit for H 2 S. KF-DNBS showed remarkable fluorescence enhancement due to H 2 S-triggered thiolysis followed by the formation of a fluorescent fluorophore ( KF )-albumin complex. The H 2 S detection limit of KF-DNBS was estimated to be 3.2 μM, and KF-DNBS achieves a high selectivity to H 2 S over biothiols by employing 2-formyl benzene boronic acid (2-FBBA) as an effective masking reagent. Furthermore, under optimized sensing conditions, KF-DNBS could be applied to accurately determine spiked H 2 S in human serum without the need for any further procedure for the removal of serum proteins.