- CoIII-Catalyzed Isonitrile Insertion/Acyl Group Migration Between C?H and N?H bonds of Arylamides
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A general efficient and site-selective cobalt-catalyzed insertion of isonitrile into C?H and N?H bonds of arylamides through C?H bond activation and alcohol assisted intramolecular trans-amidation is demonstrated. This straightforward approach overcomes the limitation by the presence of strongly chelating groups. Isolation of CoIII-isonitrile complex B has been achieved for the first time to understand the reaction mechanism.
- Kalsi, Deepti,Barsu, Nagaraju,Sundararaju, Basker
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p. 2360 - 2364
(2018/02/22)
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- NOVEL COMPOUNDS AND COMPOSITIONS FOR INHIBITION OF FASN
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The present invention relates to compounds and composition for inhibition of FASN, their synthesis, applications, and antidotes. An illustrative compound of the invention is shown below:
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- Towards applications of metal-organic frameworks in catalysis: C-H direct activation of benzoxazole with aryl boronic acids using Ni2(BDC) 2(DABCO) as an efficient heterogeneous catalyst
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A crystalline porous metal-organic framework Ni2(BDC) 2(DABCO) was synthesized and characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR), atomic absorption spectrophotometry (AAS), and nitrogen physisorption measurements. The Ni2(BDC)2(DABCO) could be used as an efficient heterogeneous catalyst for the nickel-catalyzed direct heterocycle C-H arylation reactions between azoles and arylboronic acids forming 2-arylbenzoxazoles as the principal product. This approach avoids the use of hazardous aryl halides as well as the formation of halide byproducts in the synthesis of aryl-substituted benzoxazoles. The Ni2(BDC) 2(DABCO) exhibited significantly higher catalytic activity than that of other Ni-MOFs such as Ni3(BTC)2, Ni(HBTC)(BPY), and that of some common nickel salts such as NiCl2, Ni(NO 3)2, Ni2SO4, and Ni(OAc) 2. To the best of our knowledge, application of Ni 2(BDC)2(DABCO) in the field of catalysis as well as the C-C cross coupling reaction via direct C-H functionalization using a nickel heterogeneous catalyst have not previously been reported in the literature. The Royal Society of Chemistry.
- Phan, Nam T. S.,Nguyen, Chung K.,Nguyen, Tung T.,Truong, Thanh
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p. 369 - 377
(2014/02/14)
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- Photophysical and electrochemical investigations of the fluorescent probe, 4,4′-Bis(2-benzoxazolyl)stilbene
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In solution, 4,4′-bis(2-benzoxazolyl)stilbene (BBS) was found to exhibit consistently high absolute fluorescence quantum yields (Φfl ≥ 0.88) and a monoexponential lifetime, both independent of BBS concentration. The BBS steady-state and time-resolved photophysics were investigated by different techniques to understand the various deactivation pathways. Nonradiative deactivation of BBS singlet excited state by intersystem crossing was found to be negligible. Other than fluorescence, the excited state of BBS was found to be deactivated by trans-cis photoisomerization. At low concentrations (≈5 μg/mL), UV spectroscopy and laser flash photolysis showed concordant results that the photoinduced cis isomer gradually replaced the original absorption spectrum of the pure trans isomer. However, at high concentrations (≈0.2 mg/mL), 1H NMR and DOSY measurements confirmed that irradiating BBS at 350 nm induced a conversion from the trans-BBS into its cis isomer by photoisomerization. It was further found that the stilbene moiety of both isomers was photocleaved. The resulting photoproduct was an aldehyde that was oxidized under ambient conditions to its corresponding carboxylic acid, i.e., 4-(1,3-benzoxazol-2-yl)benzoic acid. The structure of the photoproduct was unequivocally confirmed by X-ray diffraction. Spectroscopic investigation of BBS showed a limited photoisomerization after irradiation at 350 nm of a trans solution. The BBS electrochemistry showed irreversible oxidation, resulting in an unstable and highly reactive radical cation. Similarly, the cathodic process was also found to be irreversible, giving rise to a radical anion and showing its n-doping character.
- Fourati, M. Amine,Skene,Bazuin, C. Géraldine,Prud'Homme, Robert E.
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p. 836 - 844
(2013/04/23)
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- One-pot synthesis of 2-substituted benzoxazoles directly from carboxylic acids
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Methanesulfonic acid has been found to be a highly effective catalyst for a convenient and one-pot synthesis of 2-substituted benzoxazoles by the reaction of 2-aminophenol with acid chlorides, generated in situ from carboxylic acids. Aryl, heteroaryl, and arylalkyl carboxylic acids provided excellent yields of the corresponding benzoxazoles. The reaction conditions were compatible with various substituents such as chloro, bromo, nitro, methoxy, cyclopentyloxy, phenoxy, thiophenoxy, and conjugated double bonds. Benzoxazole formation was found to be general with respect to substituted 2-aminophenols.
- Kumar, Dinesh,Rudrawar, Santosh,Chakraborti, Asit K.
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experimental part
p. 881 - 887
(2009/04/11)
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- Methods for the solid phase synthesis of combinatorial libraries of benzimidazol, benzoxazoles, benzothiazoles, and derivatives thereof
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The present invention provides an efficient and versatile method for the synthesis and screening of combinatorial libraries of benzimidazoles, benzoxazoles, benzothiazoles, and derivatives thereof. In order to expedite the synthesis of large arrays of compounds possessing these core structures, a general methodology for solid phase synthesis of these derivatives is provided. Arrays of benzimidazoles, benzoxazoles, benzothiazoles, and derivatives thereof useful as peptidomimetics and for the identification of agents having antifungal, antiviral, antimicrobial, anticoagulant, and antiulcer activity, or use in the treatment of inflammation, hypertension, cancer, and other conditions can be prepared by this method.
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