- Structural chirality of cholesteric liquid crystal produces atropisomerism: Chiroptical polyisocyanides from achiral monomer in cholesteric liquid crystal matrix
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1-Naphthyl isocyanide was polymerized with Ni(II) catalyst in a cholesteric matrix at the liquid crystal (LC) temperature range. The resultant polymers showed optical activity. In this reaction, the structural chirality of cholesteric LC effectively functions to impart one-handed helicity on the corresponding polymers as an optically active atropisomer.
- Goto, Hiromasa,Ohkawa, Satoshi,Ohta, Reina
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- Bis-Selenoureas for Anion Binding: A 1H NMR and Theoretical Study
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The anion binding ability of a family of bis-selenoureas L1-L3 obtained by the reaction of 1,3-bis(aminomethyl)-benzene and phenylisoselenocyanate, p-methoxyphenylisoselenocyanate and naphtylisoselenocyanate, for L1, L2, and L3, respectively, has been tested and compared to that of previously described bis-urea analogues. Results suggest that the introduction of selenium leads to an increase in the acidity of the urea NH hydrogen atoms, and therefore to a stronger affinity (more than three-fold higher) towards anion species, in particular dihydrogen phosphate, in DMSO-d6. Theoretical calculations allowed for the optimization of the adducts receptors corroborating the experimental results.
- Caltagirone, Claudia,Ciancaleoni, Gianluca,Lippolis, Vito,Mocci, Rita,Picci, Giacomo,Zielińska-B?ajet, Mariola
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p. 1389 - 1395
(2020/08/05)
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- Mild C?F Activation in Perfluorinated Arenes through Photosensitized Insertion of Isonitriles at 350 nm
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Fluorinated compounds have become important in the fields of agrochemical industry, pharmaceutical chemistry and materials sciences. Accordingly, various methods for their preparation have been developed in the past. Fluorinated compounds can be accessed via conjugation with fluorinated building blocks, via C?H fluorination or via selective activation of perfluorinated compounds to give the partially fluorinated congeners. Especially the direct activation of C?F bonds, one of the strongest σ-bonds, still remains challenging and new strategies for C?F activation are desirable. Herein a method for the photochemical activation of aromatic C?F bonds is presented. It is shown that isonitriles selectively insert into aromatic C?F bonds while aliphatic C?F bonds remain unaffected. Mechanistic studies reveal the reaction to proceed via the indirect excitation of the isonitrile to its triplet state by photoexcited acetophenone at 350 nm. Due to the relatively mild light used, the process shows high functional group tolerance and various compounds of the class of benzimidoyl fluorides are accessible from aryl isonitriles and commercially available perfluorinated arenes. (Figure presented.).
- Weidlich, Frauke,Esumi, Naoto,Chen, Dongyang,Mück-Lichtenfeld, Christian,Zysman-Colman, Eli,Studer, Armido
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supporting information
p. 376 - 383
(2019/11/19)
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- Palladium-catalyzed secondary benzylic imidoylative reactions
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Reported herein is a palladium-catalyzed secondary benzylic imidoylative Negishi reaction leveraging the sterically bulky aromatic isocyanides as the imine source. This method allows the facile access of alkyl-, (hetero)aryl-, and alkynylzinc reagents to afford various α-substituted phenylacetone products under mild acidic hydrolysis, which are ubiquitous motifs in many pharmaceuticals and biologically active compounds. The diastereoselective reduction of imine can be accomplished to provide the expedient conversion of secondary benzylic halide into α-substituted phenethylamine derivatives with high atom economy.
- Wang, Chenglong,Wu, Licheng,Xu, Wentao,He, Feng,Qu, Jingping,Chen, Yifeng
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supporting information
p. 6954 - 6959
(2020/09/15)
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- Visible-light-induced radical cascade cyclization of oxime esters and aryl isonitriles: Synthesis of cyclopenta[: B] quinoxalines
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A visible-light-induced radical cascade cyclization of aryl isonitriles and cyclobutanone oxime esters for the synthesis of cyclopenta[b]quinoxalines has been accomplished for the first time. The key to the success of this process was the integration of the in situ-formed nitrile radical followed by the cascade radical isonitrile/nitrile insertion-cyclization. The easy introduction of substituents for both substrates and the high functional group tolerance of the reaction make it an efficient strategy to give various quinoxaline derivatives in moderate to good yields.
- Yuan, Yao,Dong, Wu-Heng,Gao, Xiao-Shuang,Xie, Xiao-Min,Zhang, Zhao-Guo
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supporting information
p. 11900 - 11903
(2019/10/11)
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- Selective Gold-Catalysed Synthesis of Cyanamides and 1-Substituted 1H-Tetrazol-5-Amines from Isocyanides
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The newly discovered gold-catalysed reaction of isocyanides with hydrazoic acid generated in situ from trimethylsilyl azide and methanol (or, alternatively, from NaN3/AcOH) produces either cyanamides or 1-substituted 1H-tetrazol-5-amines, depending on the amount of available HN3. The reaction proceeds selectively and in generally high yields of either product, thus providing a particularly convenient access to a wide range of substituted 1H-tetrazol-5-amines that are rather difficult to access otherwise.
- ?koch, Karel,Císa?ová, Ivana,?těpni?ka, Petr
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supporting information
p. 13788 - 13791
(2018/09/14)
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- Visible-Light-Induced Radical Cascade Cyclization: Synthesis of the ABCD Ring Cores of Camptothecins
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A new strategy for constructing indolizino[1,2-b]quinolin-9(11H)-ones (ring cores of camptothecins) from readily available isocyanoarenes and N-(alkyl-2-yn-1-yl)pyridin-2(1H)-ones has been developed through a visible-light-induced radical cascade cyclization process. The reaction proceeds under mild conditions with fair to excellent yields. The easy introduction of substituents for both reactants and the broad functional group tolerance of the reaction make it a straightforward route to the cores of the marketed camptothecins and their derivatives.
- Yuan, Yao,Dong, Wuheng,Gao, Xiaoshuang,Gao, Huang,Xie, Xiaomin,Zhang, Zhaoguo
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supporting information
p. 2840 - 2846
(2018/03/09)
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- Silver-Catalyzed Chemoselective [4+2] Annulation of Two Isocyanides: A General Route to Pyridone-Fused Carbo- and Heterocycles
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A silver-catalyzed chemoselective [4+2] annulation of aryl and heteroaryl isocyanides with α-substituted isocyanoacetamides was developed for the facile and efficient synthesis of 2-aminoquinolones, naphthyridines, and phenanthrolines. A mechanism for this multistep domino reaction is proposed on the basis of a13C-labeling experiment, according to which an unprecedented chemoselective heterodimerization of two different isocyanides generates an α-amidoketenimine intermediate, which undergoes 1,3-amino migration to form an α-imidoylketene, followed by 6 π electrocyclization.
- Hu, Zhongyan,Dong, Jinhuan,Men, Yang,Lin, Zhichen,Cai, Jinxiong,Xu, Xianxiu
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supporting information
p. 1805 - 1809
(2017/02/05)
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- USE OF INHIBITOR OF APOPTOSIS PROTEIN (IAP) ANTAGONISTS IN HIV THERAPY
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Provided herein is the use of compounds that modulate the activity of inhibitor of apoptosis proteins (IAPs), alone or in combination with other therapeutic agents, in the treatment of human immunodeficiency virus (HIV).
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Paragraph 00505
(2015/12/30)
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- C-F Activation in Perfluorinated Arenes with Isonitriles under UV-Light Irradiation
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Due to the great value of fluorinated arenes in agrochemistry, medicinal chemistry and materials science, development of methods for preparation of fluorinated arenes is of high importance. They can be either accessed by arene fluorination or by partial arene defluorination. However, the carbon-fluorine bond belongs to the strongest σ-bonds, which renders C-F activation highly challenging. Here it is shown that aryl and alkyl isonitriles efficiently activate the strong C-F bond in perfluoroarenes by simple UV irradiation under mild conditions. Reactions proceed by formal direct insertion of the isonitrile into the C-F bond without any transition metal. Activation occurs at arene C-F bonds whereas aliphatic C-F bonds remain unreacted. For selected perfluoroarenes C-F activation occurs with high regioselectivity and resulting imidoyl fluorides are transformed into other valuable compounds. Theoretical studies give insights into the reaction mechanism.
- Dewanji, Abhishek,Mück-Lichtenfeld, Christian,Bergander, Klaus,Daniliuc, Constantin G.,Studer, Armido
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supporting information
p. 12295 - 12298
(2015/08/25)
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- A general simple methodology for synthesis of isonitriles using benzene-1,3-disulfonyl dichloride
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Isonitrile derivatives have been synthesized in good to high yields by dehydration of aliphatic and aromatic formamides in the presence of benzene-1,3-disulfonyl dichloride as easy and efficient reagent.
- Ghorbani-Vaghei, Ramin,Amiri, Mostafa,Veisi, Hojat
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- Synthesis of sugar-derived isoselenocyanates, selenoureas, and selenazoles
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Aryl, alkyl, and sugar-derived isoselenocyanates were prepared by a one-pot procedure starting from the corresponding formamides, using triphosgene as a dehydrating agent, triethylamine, and black selenium powder. The preparation of sugar selenoureas by coupling of O-protected sugar-derived isoselenocyanates with different amines, and by coupling of unprotected glycopyranosyl amines with phenyl isoselenocyanate was also accomplished. The synthesis of a glucopyranos-2-yl-selenazole starting from O-protected 2-amino-2-deoxy-d-glucose by coupling with benzoyl isoselenocyanate, Se-alkylation with phenacyl bromide, and acid-catalyzed dehydration is also reported. Unprotected N-(β-d-glucopyranosyl)-N′-phenylselenourea was transformed into a 1,2-trans-fused bicyclic isourea upon treatment with aqueous hydrogen peroxide; the same isourea was prepared by a one-pot three-step procedure from β-d-glycopyranosylamine by thiophosgenation, coupling with aniline, and HgO-mediated desulfurization.
- López, óscar,Maza, Susana,Ulgar, Víctor,Maya, Inés,Fernández-Bola?os, José G.
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experimental part
p. 2556 - 2566
(2009/08/08)
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- A new Method for the Reduction of Isocyanates to Isocyanides
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Both diphenyl-t-butylsilyl-lithium and trichlorosilane-triethylamine reduce isocyanates to isocyanides in high yield under mild conditions.
- Baldwin, Jack E.,Bottaro, Jeffrey C.,Riordan, Peter D.,Derome, Andrew E.
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p. 942 - 943
(2007/10/02)
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