- Manganese(I) Catalyzed α-Alkenylation of Amides Using Alcohols with Liberation of Hydrogen and Water
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Herein, unprecedented manganese-catalyzed direct α-alkenylation of amides using alcohols is reported. Aryl amides are reacted with diverse primary alcohols, which provided the α,β-unsaturated amides in moderate to good yields with excellent selectivity. Mechanistic studies indicate that Mn(I) catalyst oxidizes the alcohols to their corresponding aldehydes and also plays an important role in efficient C═C bond formation through aldol condensation. This selective olefination is facilitated by metal-ligand cooperation by the aromatization-dearomatization process operating in the catalytic system. Biorenewable alcohols are used as alkenylation reagents for the challenging α-alkenylation of amides with the highly abundant base metal manganese as a catalyst, which results in water and dihydrogen as the only byproduct, making this catalytic transformation attractive, sustainable, and environmentally benign.
- Pandia, Biplab Keshari,Gunanathan, Chidambaram
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p. 9994 - 10005
(2021/07/31)
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- New half-sandwich (η6-p-cymene)ruthenium(II) complexes with benzothiazole hydrazone Schiff base ligand: Synthesis, structural characterization and catalysis in transamidation of carboxamide with primary amines
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Few half-sandwich (η6-p-cymene) ruthenium(II) complexes supported by benzothiazole hydrazone Schiff bases were synthesized. The new complexes possess the general formulae [Ru(η6-p-cymene)(L)Cl] (1-3) (L = salicyl((2-(benzothiazol-2-yl)hydrazono)methylphenol) (SAL-HBT), 2-((2-(benzothiazol-2-yl)hydrazono)methyl)-6 methoxyphenol) (VAN-HBT) or naphtyl-2-((2-(benzothiazol-2-yl)hydrazono)methyl phenol) (NAP-HBT). All compounds were fully studied by analytical, spectroscopic techniques (IR, NMR) and also by mass spectrometry. The solid state structure of the complex 3 reveals the coordination of p-cymene moieties with ruthenium(II) in a three-legged piano-stool geometry along with benzothiazole hydrazone Schiff base ligand in a monobasic bidentate fashion. The catalytic properties of the complexes were screened in transamidation of primary amide with amines after optimization with respect to solvent, substituents, time and catalyst loading. The results show that the complex 3 is the most efficient catalyst for the transamidation of carboxamides with amines.
- Vijayapritha, Subbarayan,Viswanathamurthi, Periasamy
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supporting information
(2020/10/18)
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- Iron Tridentate Carbene Single Site Catalysts
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The present disclosure provides iron-containing catalyst compounds having a carbene ligand. Catalyst compounds of the present disclosure can be asymmetric, having an electron donating side of the catalyst and an electron deficient side of the catalyst. In
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Paragraph 0229; 0230
(2019/05/24)
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- Structure-activity relationships for highly potent half-sandwich organoiridium(III) anticancer complexes with C^N-chelated ligands
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We herein report the synthesis, characterization, catalytic ability in converting coenzyme NADH to NAD+ and anticancer activity of half-sandwich iridium(III) complexes, [(η5-Cpxbiph)Ir(C^N)Cl]PF6 ?, where Cpxbiph = tetramethyl(biphenyl)cyclopentadienyl, C^N = varying imine-N-heterocyclic carbene ligands. The molecular structure of [(η5-Cpxbiph)Ir(L6)Cl]PF6 (complex Ir6), exhibiting the familiar “piano-stool” geometry, has been authenticated by X-ray crystallography. The anticancer activities of these complexes can be governed via substituent effects of three tunable domains and the ligand substituted variants offer an effective chelate ligand set that distinguishes anticancer activity and catalytic ability. Notably, complex Ir6 displays the greatest cytotoxic activities (IC50 = 0.85 μM), whose anticancer activity is more approximately 25-fold higher than that of cisplatin. The initial cell death mechanistic insight displays that this group of iridium(III) complexes exerts anticancer effects via cell cycle arrest, apoptosis induction and loss of the mitochondrial membrane potential. In addition, the confocal microscopy imaging shows that the complex Ir6 can damage lysosome. Overall, preliminary structure–activity relationships study and understanding of the cell death mechanism perhaps provide a rational strategy for enhancing anticancer activity of this family of complexes.
- Yang, Yuliang,Guo, Lihua,Ge, Xingxing,Shi, Shaopeng,Gong, Yuteng,Xu, Zhishan,Zheng, Xiaofeng,Liu, Zhe
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- Acylation of Phenols, Alcohols, Thiols, Amines and Aldehydes Using Sulfonic Acid Functionalized Hyper-Cross-Linked Poly(2-naphthol) as a Solid Acid Catalyst
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Abstract: The hyper-cross-linked porous poly(2-naphthol) fabricated by the Friedel–Crafts alkylation of 2-naphthol has been functionalized with sulfonic acid to obtain a solid acid catalyst. The catalyst is applied for the protection of phenol, alcohols, thiols, amines and aldehydes with acetic anhydride at room temperature. The catalytic protection using the new solid acid is featured by achieving high yield at neat condition, needing no aqueous work-up and/or chromatographic separation, and showing excellent recycling efficiency, suggesting the potential of this sulfonated porous polymers as a new protection protocol in a wide range of sustainable chemical reactions. Graphical Abstract: [Figure not available: see fulltext.].
- Kalla, Reddi Mohan Naidu,Reddy, Sirigireddy Sudharsan,Kim, Il
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p. 2696 - 2705
(2019/05/28)
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- Novel and Versatile Imine-N-Heterocyclic Carbene Half-Sandwich Iridium(III) Complexes as Lysosome-Targeted Anticancer Agents
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We, herein, report the synthesis, characterization, luminescence properties, anticancer, and antibacterial activities of a family of novel half-sandwich iridium(III) complexes of the general formula [(n5-Cpx)Ir(C^N)Cl]PF6- [Cpx = pentamethylcyclopentadienyl (Cp) or tetramethyl(biphenyl)-cyclopentadienyl (Cpxbiph)] bearing versatile imine-N-heterocyclic carbene ligands. In this complex framework, substituents on four positions could be modulated, which distinguishes this class of complex and provides a large amount of flexibility and opportunity to tune the cytotoxicity of complexes. The X-ray crystal structures of complexes 4 and 10 exhibit the expected "piano-stool" geometry. With the exception of 1, 2, and 11, each complex shows potent cytotoxicity, with IC50 (half-maximum inhibitory concentration) values ranging from 1.99 to 25.86 μM toward A549 human lung cancer cells. First, the effect of four positions bearing different substituents in the complex framework on the anticancer activity, that is, structure-activity relationship, was systematically studied. Complex 8 (IC50 = 1.99 μM) displays the highest anticancer activities, whose cytotoxicity is more than 10-fold higher than that of the clinical platinum drug cisplatin against A549 cancer cells. Second, their chemical reactivity including nucleobases binding, catalytic activity in converting coenzyme NADH to NAD+, reaction with glutathione (GSH), and bovine serum albumin (BSA) binding is investigated. No reaction with nucleobase is observed. However, these iridium(III) complexes bind rapidly to GSH and can catalyze oxidation of NADH to NAD+. In addition, they show moderate binding affinity to BSA and the fluorescence quenching of BSA by the iridium (III) complexes is due to the static quenching. Third, the mode of cell death was also explored through flow cytometry experiments, including cell cycle, apoptosis induction, reactive oxygen species (ROS) and mitochondrial membrane potential. It seems that cell cycle perturbation, apoptosis induction, increase of ROS level and loss of mitochondrial membrane potential together contribute to the anticancer potency of these complexes. Last, the use of confocal microscopy provides insights into the microscopic mechanism that the typical and most active complex 8 enters A549 lung cancer cells mainly through energy-dependent pathway and is located in lysosome. Furthermore, lysosome damage and nuclear morphology were detected by confocal microscopy. Nuclear condensation and apoptotic bodies may finally induce cells apoptosis. Interestingly, complex 8 also shows antibacterial activity against Gram-positive Staphylococcus aureus. This work may provide an alternative and effective strategy to smart design of potent organometallic half-sandwich iridium(III) anticancer drugs.
- Yang, Yuliang,Guo, Lihua,Tian, Zhenzhen,Gong, Yuteng,Zheng, Hongmei,Zhang, Shumiao,Xu, Zhishan,Ge, Xingxing,Liu, Zhe
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p. 11087 - 11098
(2018/09/14)
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- Imine-N-Heterocyclic Carbenes as Versatile Ligands in Ruthenium(II) p-Cymene Anticancer Complexes: A Structure–Activity Relationship Study
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A family of novel imine-N-heterocyclic carbene ruthenium(II) complexes of the general formula [(η6-p-cymene)Ru(C^N)Cl]PF6? (where C^N is an imine-N-heterocyclic carbene chelating ligand with varying substituents) have been prepared and characterized. In this imine-N-heterocyclic carbene chelating ligand framework, there are three potential sites that can be modified, which distinguishes this class of ligand and provides a body of flexibilities and opportunities to tune the cytotoxicity of these ruthenium(II) complexes. The influence of substituent effects of three tunable domains on the anticancer activity and catalytic ability in converting coenzyme NADH to NAD+ is investigated. This family of complexes displays an exceedingly distinct anticancer activity against A549 cancer cells, despite their close structural similarity. Complex 9 shows the highest anticancer activity in this series against A549 cancer cells (IC50=14.36 μm), with an approximately 1.5-fold better activity than the clinical platinum drug cisplatin (IC50=21.30 μm) in A549 cancer cells. Mechanistic studies reveal that complex 9 mediates cell death mainly through cell stress, including cell cycle arrest, inducing apoptosis, increasing intracellular reactive oxygen species (ROS) levels, and depolarization of the mitochondrial membrane potential (MMP). Furthermore, lysosomal damage is also detected by confocal microscopy.
- Yang, Yuliang,Guo, Lihua,Tian, Zhenzhen,Liu, Xicheng,Gong, Yuteng,Zheng, Hongmei,Ge, Xingxing,Liu, Zhe
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p. 2923 - 2933
(2018/09/12)
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- COMPOUNDS AND COMPOSITIONS FOR TREATING CONDITIONS ASSOCIATED WITH NLRP ACTIVITY
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In one aspect, compounds of Formulae (I) and (II), or pharmaceutically acceptable salts thereof, are featured; Formula (I), Formula (II) or a pharmaceutically acceptable salt thereof, wherein the variables shown in Formulae (I) and (II) can be as defined anywhere herein.
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Page/Page column 195
(2017/11/15)
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- Sulfated choline ionic liquid-catalyzed acetamide synthesis by grindstone method
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Sulfated choline ionic liquid (SCIL) has been found to be an efficient solid acid IL catalyst for the protection of amine groups with acetic anhydride under solvent-free grindstone conditions. The attractive features of this new catalytic methodology include its sustainability, facile work-up procedure, economic viability, and biodegradability. The SCIL catalyst was characterized using infrared spectroscopy, wide-angle X-ray scattering analysis, and scanning electron microscopy with energy dispersive X-ray spectroscopy. The catalyst could be reused six times without significant loss in activity. Furthermore, no chromatographic separations were needed to obtain the desired products.
- Kalla, Reddi Mohan Naidu,Lim, Jaehwa,Bae, Jaeyeong,Kim, Il
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supporting information
p. 1595 - 1599
(2017/04/03)
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- Imino Carbene Compounds and Derivatives, and Catalyst Compositions Made Therefrom
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The present invention provides imino carbene compounds and their derivatives, catalyst compositions containing these compounds in combination with an activator, and polymerization processes using these catalyst compositions to polymerize one or more olefi
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Page/Page column 44
(2012/11/07)
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- Silver triflate catalyzed acetylation of alcohols, thiols, phenols, and amines
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A variety of alcohols, thiols, phenols, and amines were subjected to acetylation reaction using acetic anhydride in the presence of catalytic quantity of silver triflate. The method described has a wide range of applications, proceeds under mild conditions, does not involve cumbersome workup, and the resulting products are obtained in high yields within a reasonable time. Georg Thieme Verlag Stuttgart · New York.
- Das, Rima,Chakraborty, Debashis
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experimental part
p. 1621 - 1625
(2011/06/25)
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- Synthesis of some very bulky N,N′-disubstituted amidines and initial studies of their coordination chemistry
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N,N′-Bis(2,6-diisopropylphenyl)-4-toluamidine, -4-anisylamidine and -acetamidine have been prepared for the first time from 2,6-diisopropylaniline and the acid chlorides via the corresponding imidoyl chlorides. The crystal structures of all three amidines were determined, indicating that the first is a disordered mixture of Z-anti and E-syn tautomeric forms, the second Z-anti, and the third E-anti in the solid state. Despite these differences, all three form identical coordination complexes with Mo(CO)3 in which the ligand is in the Z-anti geometry, and the metal is π-coordinated to the imino 2,6-diisopropylphenyl ring, and the amino N-H unit is directed towards metal. The coordination mode was confirmed by single-crystal X-ray structure determination of the toluamidine and methylamidine complexes with Mo(CO)3. In the case only of the methylamidine, an isolable intermediate is first formed in which the neutral amidine is coordinated in a monodentate fashion to an Mo(CO)5 unit. The crystal structure of this complex shows that the ligand is in the E-anti geometry, with the imino nitrogen coordinated to Mo, d(Mo-N) = 2.352(2) A. The structures are closely related in that the initial Mo(CO)5 N-coordination sets up the metal for conversion to the more thermodynamically stable π-coordinated Mo(CO)3 complex. The high steric bulk of these superamidine ligands is seen in the failure of any of them to form the metal-metal bonded Mo2(amidinate)4 complexes typically prepared using common, less bulky, amidines.
- Boere, Rene T.,Klassen, Vicki,Wolmershaeuser, Gotthelf
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p. 4147 - 4154
(2007/10/03)
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- Phosphoric Anhydride in Reactions with Acetanilides
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Reactions of phosphoric anhydride with acetanilides yield an equilibrium mixture of N- and O-dihydroxyphosphorylated acetanilide derivatives. Reaction of acetic acid 2,6-diisopropylanilide with phosphoric anhydride yields 2-methyl-1,3-diphenyl-3-acetylamidine.
- Zavlin,Efremov
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p. 872 - 877
(2007/10/03)
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- ACAT inhibitors derived from hetero-Diels-Alder cycloadducts of thioaldehydes
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Acyl-CoA:cholesterol acyltransferase (ACAT) is the enzyme largely responsible for intracellular cholesteror esterification. A systemic inhibitor of ACAT is believed to be able to slow or even reverse the atherosclerotic process. Towards that goal, a series of cyclic sulfides, derived from the hetero-Diels-Alder reaction of thioaldehydes with 1,3-dienes, and bearing carboxamide substituents, were prepared and evaluated for in vitro (in several tissues and species) and ex vivo ACAT inhibition. Minor changes in subsequent structure were found to have a significant effect in optimization of the biological activity of this series of compounds.
- Wilde, Richard G.,Billheimer, Jeffrey T.,Germain, Sandie J.,Hausner, Elizabeth A.,Meunier, Paul C.,Munzer, Deborah A.,Stoltenborg, Janet K.,Gillies, Peter J.,Burcham, Deborah L.,Huang, Shiew-Mai,Klaczkiewicz, John D.,Ko, Soo S.,Wexler, Ruth R.
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p. 1493 - 1513
(2007/10/03)
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- Revisitation of Formaldehyde Aniline Condensation. VIII. - Monomeric N-Methylene Anilines
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A convenient, high yield "dry" method of synthesis of monomeric N-methyleneanilines (6a-i) and the characterization of the products by m.s., 1H- and 13C-n.m.r. and i.r. are reported, improving previous procedures and describing new compounds.It appeared that the existence of monomeric N-methyleneanilines is stricly related to the presence of enough steric hindrance to oligomerization by substituents in ortho positions.Moreover, some addition products of formaldehyde to an amine and its corresponding imines are tentatively identified on the basis of the observed mass spectrum of the whole reaction mixture.The reaction products of formaldehyde with 2,6-dimethylaniline (1a) provided an example of a mobile equilibrium between monomeric and trimeric imine.
- Giumanini, Angelo G.,Verardo, Giancarlo,Polana, Marco
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p. 161 - 174
(2007/10/02)
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