Search results for "Highly selective"
showing 10 items of 22 documents
Dual role of silver in a fluorogenic N-squaraine probe based on Ag(i)–π interactions
2021
In the presence of Ag(I), the monoanion of cyano-N-squaraine (I) generates an intense fluorescence turn-on response. Experimental evidence and DFT calculations reveal a sequence of deprotonation-coordination events in which the Ag(I) ions play a dual role as a Lewis acid and coordinating metal. The observed effect is highly selective for Ag(I) compared to other metals.
Unexpected Scholl Reaction of 6,7,13,14-Tetraarylbenzo[k]tetraphene: Selective Formation of Five-Membered Rings in Polycyclic Aromatic Hydrocarbons
2016
Cyclodehydrogenation is a versatile reaction that has enabled the syntheses of numerous polycyclic aromatic hydrocarbons (PAHs). We now describe a unique Scholl reaction of 6,7,13,14-tetraarylbenzo[k]tetraphene, which "unexpectedly" forms five-membered rings accompanying highly selective 1,2-shift of aryl groups. The geometric and optoelectronic nature of the resulting bistetracene analogue with five-membered rings is comprehensively investigated by single-crystal X-ray, NMR, UV-vis absorption, and cyclic voltammetry analyses. Furthermore, a possible mechanism is proposed to account for the selective five-membered-ring formation with the rearrangement of the aryl groups, which can be ration…
Targeting of the Leishmania Mexicana cysteine protease CPB2.8 ΔCTE by decorated fused benzo[b] thiophene scaffold.
2016
A potent and highly selective anhydride-based inhibitor of Leishmania mexicana cysteine protease CPB2.8ΔCTE (IC50 = 3.7 μM) was identified. The details of the interaction of the ligand with the enzyme active site were investigated by NMR biomimetic experiments and docking studies. Results of inhibition assays, NMR and theoretical studies indicate that the ligand acts initially as a non-covalent inhibitor and later as an irreversible covalent inhibitor by chemoselective attack of CYS 25 thiolate to an anhydride carbonyl.
Synthesis of tritium labeled 7α-methoxycarbonyl-15β,16β-methylene-3-oxo-17α-pregn-4-ene-21, 17-carbolactone, [3H]SH-D515, a highly selective tracer f…
1988
The synthesis of 7α-methoxycarbonyl-15β,16β-methylene-3-oxo-17α-pregn-4-ene-21,17-carbolactone (5, SH-D515, ZK 91587), a potent aldosterone antagonist exhibiting a strong and very selective binding to the mineralocorticoid receptor and the tritiated analog 6 is reported.
Unsaturated syn- and anti-1,2-Amino Alcohols by Cyclization of Allylic Bis-trichloroacetimidates. Stereoselectivity Dependence on Substrate Configura…
2014
Disubstituted allylic bis-imidates undergo Lewis acid catalyzed or spontaneous cyclization to oxazolines, which are precursors of unsaturated amino alcohols. Stereoselectivity of the cyclization is mainly determined by the substrate configuration. Highly selective cis-oxazoline formation is achieved starting from anti-E-bis-imidates while trans-oxazoline predominantly forms from anti-Z-bis-imidates. On the basis of DFT calculations, the stereoselectivity trends can be explained by the formation of the energetically most stable carbenium ion conformation, followed by the cyclization via most favorable bond rotations.
Sensitive and selective plasmonic assay for spermine as biomarker in human urine.
2014
A simple, fast, and highly selective and sensitive colorimetric assay to detect nanomolar levels of spermine in human urine (healthy donors, cancer patients) is reported. This assay is based on the absence of a competitive organic capping on the gold nanoparticles together with the high affinity of the amine groups of the analyte for the nanoparticle surface.
Highly Selective Detection of Nerve‐Agent Simulants with BODIPY Dyes
2014
Two chromo-fluorogenic probes, each based on the boron dipyrromethene core, have been developed for the detection of nerve-agent mimics. These chemosensors display both a color change and a significant enhancement of fluorescence in the presence of diethylcyanophosphonate (DCNP) and diisopropylfluorophosphate (DFP). No interference from other organophosphorus compounds or acids has been observed. Two portable chemosensor kits have been developed and tested to demonstrate its practical application in real-time monitoring.
A Boron Dipyrromethene (BODIPY)-Based Cu(II) -Bipyridine Complex for Highly Selective NO Detection.
2015
[EN] A BODIPY-containing Cu-II-bipyridine complex for the simple selective fluorogenic detection of NO in air and in live cells is reported. The detection mechanism is based on NO-promoted Cu-II to Cu-I reduction, followed by demetallation of the complex, which results in the clearly enhanced emission of the boron dipyrromethene (BODIPY) unit.
ChemInform Abstract: Gold(I)-Catalyzed Reactions of 1-(ortho-Alkynylaryl)ureas: Highly Selective Heterocyclization and Synthesis of Mixed N,O-Acetals.
2014
Treatment of alkynylureas (I) with trifluoroethanol in the presence of a Au/Ag catalytic system provides N-6-exo-dig heterocyclization products (III) and in some cases open chain acetals as side products.
Gold(I)-Catalyzed Reactions of 1-(ortho-Alkynylaryl)ureas: Highly Selective Heterocyclization and Synthesis of MixedN,O-Acetals
2014
Treatment of alkynylureas (I) with trifluoroethanol in the presence of a Au/Ag catalytic system provides N-6-exo-dig heterocyclization products (III) and in some cases open chain acetals as side products.