- Chemoselective Radical Dehalogenation and C-C Bond Formation on Aryl Halide Substrates Using Organic Photoredox Catalysts
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Despite the number of methods available for dehalogenation and carbon-carbon bond formation using aryl halides, strategies that provide chemoselectivity for systems bearing multiple carbon-halogen bonds are still needed. Herein, we report the ability to tune the reduction potential of metal-free phenothiazine-based photoredox catalysts and demonstrate the application of these catalysts for chemoselective carbon-halogen bond activation to achieve C-C cross-coupling reactions as well as reductive dehalogenations. This procedure works both for conjugated polyhalides as well as unconjugated substrates. We further illustrate the usefulness of this protocol by intramolecular cyclization of a pyrrole substrate, an advanced building block for a family of natural products known to exhibit biological activity.
- Poelma, Saemi O.,Burnett, G. Leslie,Discekici, Emre H.,Mattson, Kaila M.,Treat, Nicolas J.,Luo, Yingdong,Hudson, Zachary M.,Shankel, Shelby L.,Clark, Paul G.,Kramer, John W.,Hawker, Craig J.,Read De Alaniz, Javier
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p. 7155 - 7160
(2016/08/30)
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- Synthesis of 2,4-dihalogenofluorobenzenes and their antimicrobial and antifungal activity studies
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The aim of this study was to synthesize and identify 2,4- dihalogenofluorobenzene (or trihalogenobenzene) derivatives by spectroscopic means, 1H-NMR and 19F-NMR. The 2,4-dihalofluorobenzene derivatives considered were 2,4-dichlorofluorobenzene (1), 2-bromo-4- chlorofluorobenzene (2), 2-iodo-4-chlorofluorobenzene(3), 2,5- dichlorofluorobenzene (4), 2-bromo-5-chlorofluorobenzene (5), 2-iodo-5-chlorofluorobenzene (6). The in vitro antibacterial and antifungal activities of trihalogenobenzene derivatives were studied against the bacteria Staphylococcus aureus ATCC 25923 Gram(+), Bacillus cereus ATCC 6633 Gram(+), Micrococcus flavus (clinical isolate) Gram(+), Morgenella morganii (clinical isolate) Gram(-), Escherichia coli ATCC 27853 Gram(-) and fungus Candida albicans (clinical isolate), obtained from the biology departments of the Pamukkale and Gazi Universities. The antibacterial and antifungal activities were measured by minimum inhibition concentration (MIC) method and the disc-diffusion method used to measure zone diameter against Gram-positive and Gram-negative bacteria and fungi. All these bacteria and fungi were studied against antibiotics to compare the zone diameters with the results from our treatments. Birkhaeuser 2007.
- Katircioglu, Hikmet,Logoglu, Elif,Tilki, Tahir,Oektemer, Atilla
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p. 205 - 212
(2008/12/21)
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