Photochemical trifluoromethylation of some biologically significant imidazoles

Kimoto, Hiroshi; Fujii, Shozo; Cohen, Louis A.

doi:10.1021/jo00180a021

Cited by 67 publications

(15 citation statements)

References 3 publications

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“…Thus 2-CF 3 His is a very weak base that would almost certainly remain in the neutral form at any pH accessible in the electrophysiology assay. We therefore prepared 2-CF 3 His using a literature procedure (Figure 4B; Kimoto et al, 1984), and appended it to a suppressor tRNA as described for 2-CH 3 His.…”

Section: Resultsmentioning

confidence: 99%

Structural Requirements in the Transmembrane Domain of GLIC Revealed by Incorporation of Noncanonical Histidine Analogs

Rienzo

Lummis

Dougherty

2014

Chemistry & Biology

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SUMMARY The cyanobacterial pentameric ligand-gated ion channel GLIC, a homolog of the Cys-loop receptor superfamily, has provided useful structural and functional information about its eukaryotic counterparts. X-ray diffraction data and site-directed mutagenesis have previously implicated a transmembrane histi-dine residue (His234) as essential for channel function. Here, we investigated the role of His234 via synthesis and incorporation of histidine analogs and α-hydroxy acids using in vivo nonsense suppression. Receptors were expressed heterologously in Xenopus laevis oocytes, and whole-cell voltage-clamp electrophysiology was used to monitor channel activity. We show that an interhelix hydrogen bond involving His234 is important for stabilization of the open state, and that the shape and basicity of its side chain are highly sensitive to perturbations. In contrast, our data show that two other His residues are not involved in the acid-sensing mechanism.

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Section: Resultsmentioning

confidence: 99%

Structural Requirements in the Transmembrane Domain of GLIC Revealed by Incorporation of Noncanonical Histidine Analogs

Rienzo

Lummis

Dougherty

2014

Chemistry & Biology

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“…By using a catalyst system consisting of 20 mol % of CuI and 1,10-phenanthroline in DMSO at 60 8C, the product was obtained in 71 % yield, which could be increased to 80 % when 3 rather than 2 equivalents of 3 a were employed (Table 2, entry 9). Under these reaction conditions, salts 3 b-d were investigated (Table 2, entries [10][11][12]. A nearly quantitative conversion of 4 a into 5 a was observed when the more reactive CF 3 source, 3 c, was employed (Table 2, entry 11).…”

Section: Resultsmentioning

confidence: 99%

“…[9] Radical trifluoromethylations are possible starting with a range of trifluoromethyl derivatives, including CF 3 I, [10] (CF 3 ) 2 Hg, [11] (CF 3 ) 2 N 2 , [12] CF 3 SO 2 Na/tBuOOH, [13] or CF 3 N(NO)SO 2 Ph. [14] However, the substrate scope of each of the above reactions is limited.…”

Section: Introductionmentioning

confidence: 99%

Copper‐Catalyzed Trifluoromethylation of Aryl Iodides with Potassium (Trifluoromethyl)trimethoxyborate

Knauber

Arikan

Röschenthaler

et al. 2011

Chemistry A European J

268

107

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Potassium (trifluoromethyl)trimethoxyborate is introduced as a new source of CF(3) nucleophiles in copper-catalyzed trifluoromethylation reactions. The crystalline salt is stable on storage, easy to handle, and can be obtained in near-quantitative yields simply by mixing B(OMe)(3), CF(3)SiMe(3), and KF. The trifluoromethylation reagent allows the conversion of various aryl iodides into the corresponding benzotrifluorides in high yields under mild, base-free conditions in the presence of catalytic quantities of a Cu(I)/1,10-phenanthroline complex.

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“…Erste Arbeiten zur radikalischen Trifluormethylierung von Arenen durch photochemisch induzierte radikalische Addition von Trifluoriodmethan an substituierte Benzole [275] und Imidazole [276] oder Blitzthermolyse von Aryltrifluoracetaten [277] ergaben ein Gemisch trifluormethylierter Produkte in ca. 15 % Ausbeute.…”

Section: Elektrophile Synthesemethoden Für Trifluormethylierte Sp 2 -unclassified

Einführung von Fluor und fluorhaltigen funktionellen Gruppen

2013

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Die wichtigsten konzeptionellen Fortschritt auf dem Gebiet der Fluorierungen der letzten zehn Jahre wurden durch die Organo‐ und Übergangsmetallkatalyse ermöglicht. Die schwierigste Umwandlung ist weiterhin die Bildung der C‐F‐Stammbindung, was in erster Linie eine Folge der hohen Hydratationsenergie von Fluorid, starker Metall‐Fluor‐Bindungen und der hoch polarisierten Bindungen zu Fluor ist. Den meisten Fluorierungen fehlt es immer noch an Allgemeingültigkeit, Vorhersagbarkeit und Kosteneffizienz. Trotz der Einschränkungen sind fluorierte Verbindungen mit modernen Fluorierungsmethoden leichter zugänglich als je zuvor. Vor allem beginnen sich die modernen Methoden auf Forschungsgebiete auszuwirken, die keine großen Materialmengen benötigen, z. B. die Wirkstoffentwicklung und die Positronenemissionstomographie. Diese Entwicklungen werden in diesem Aufsatz zusammengefasst und vor dem Hintergrund konventioneller Fluorierungsmethoden diskutiert.

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Photochemical trifluoromethylation of some biologically significant imidazoles

Cited by 67 publications

References 3 publications

Structural Requirements in the Transmembrane Domain of GLIC Revealed by Incorporation of Noncanonical Histidine Analogs

Structural Requirements in the Transmembrane Domain of GLIC Revealed by Incorporation of Noncanonical Histidine Analogs

Copper‐Catalyzed Trifluoromethylation of Aryl Iodides with Potassium (Trifluoromethyl)trimethoxyborate

Einführung von Fluor und fluorhaltigen funktionellen Gruppen

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