- Cyclometalated Half-Sandwich Iridium(III) Complexes: Synthesis, Structure, and Diverse Catalytic Activity in Imine Synthesis Using Air as the Oxidant
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Four air-stable cyclometalated half-sandwich iridium complexes 1-4 with C,N-donor Schiff base ligands were prepared through C-H activation in moderate-to-good yields. These complexes have been well characterized, and their exact structure was elaborated on by single-crystal X-ray analysis. The iridium(III) complexes 1-4 showed good catalytic activity in the imine synthesis under open-flask conditions (air as the oxidant) from primary amine oxidative homocoupling, secondary amine dehydrogenation, and the cross-coupling reaction of amine and alcohol. Substituents bonded on the ligands of the iridium complexes displayed little effect on the catalytic efficiency. The stability and good catalytic efficiency of the iridium catalysts, mild reaction conditions, and substrate universality showed their potential application in industrial production.
- Li, Rong-Jian,Ling, Chun,Lv, Wen-Rui,Deng, Wei,Yao, Zi-Jian
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p. 5153 - 5162
(2021/05/04)
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- Efficient Co-Catalyzed Double Hydroboration of Nitriles: Application to One-Pot Conversion of Nitriles to Aldimines
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The commercially available and bench-stable Co(acac)2/dpephos system is employed as a precatalyst for selective and efficient room temperature hydroboration of organic nitriles with HBPin to produce a series of N,N-diborylamines [RN(BPin)2], which react in situ with aldehydes to give aldimines. Formation of aldimines from N,N-diborylamines does not require a dehydrating agent, is applicable to a wide range of N,N-diborylamine and aldehyde substrates and is highly chemoselective, being unaffected by various common functional groups, such as alkenes, alkynes, secondary amines, ketones, esters, amides, carboxylic acids, pyridines, nitriles, and nitro compounds. The overall transformation represents a synthetically valuable approach to aldimines from nitriles and can be performed in a sequential one-pot manner, tolerating ester, lactone, carboxamide and unactivated alkene functionalities.
- Gudun, Kristina A.,Slamova, Ainur,Hayrapetyan, Davit,Khalimon, Andrey Y.
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supporting information
p. 4963 - 4968
(2020/04/17)
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- Three novel Cd(II) dithiocarbamate complexes: synthesis, structural diversity and fluorescence properties
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Three new homoleptic cadmium (II) dithiocarbamate complexes having molecular formula [Cd(KL)2], (KL1 = C15H13N1F1S2) (1); (L2 = C13H11N1F1S2) (2); (L3 = C11H14N1O1S2) (3), have been synthesized and characterized by elemental analysis, spectroscopy (IR, 1H and 13CNMR and UV–Vis). Single crystal X-ray studies confirm that the complex 1 crystallises in Orthorhombic with space group Pna21 and holding dimeric structure. In this complex Cd2+ having distorted octahedral geometry about the metal centre forms 1D coordination polymeric structures. The dimeric form of complex 2 and 3 crystallizes in triclinic crystal lattice with space group P-1.
- Singh, Ravi Pratap,Maurya, Vinay Kumar,Prasad, Lal Bahadur,Siddiqui, Kafeel Ahmad
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p. 2867 - 2876
(2020/07/03)
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- Air-Stable Half-Sandwich Iridium Complexes as Aerobic Oxidation Catalysts for Imine Synthesis
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Several N,O-coordinate half-sandwich iridium complexes, 1-5, containing constrained bulky β-enaminoketonato ligands were prepared and clearly characterized. Single-crystal X-ray diffraction characterization of these complexes indicates that the iridium center adopts a distorted octahedral geometry. Complexes 1-5 showed good catalytic efficiency in the oxidative homocoupling of primary amines, dehydrogenation of secondary amines, and the oxidative cross-coupling of amines and alcohols, which furnished various types of imines in good yields and high selectivities using O2 as an oxidant under mild conditions. No distinctive substituent effects of the iridium catalysts were observed in these reactions. The diverse catalytic activity, broad substrate scope, mild reaction conditions, and high yields of the products made this catalytic system attractive in industrial processes.
- Deng, Wei,Fan, Xiao-Nan,Ou, Hui-Dan,Yao, Zi-Jian
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supporting information
(2020/04/02)
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- Time-Dependent Switching of Constitutional Dynamic Libraries and Networks from Kinetic to Thermodynamic Distributions
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The distribution of the constituents of a constitutional dynamic library (CDL) may undergo time-dependent changes as a function of the kinetics of the processes generating the CDL from its components. Thus, the constitutional dynamic network (CDN) representing the connections between the constituents changes from a kinetic distribution to the thermodynamic one as a function of time. We investigated the behavior of dynamic covalent libraries (DCLs) of four constituents generated by reversible formation of C═N bonds between four components, 2 aldehydes and 2 amino compounds, both in absence and in the presence of metal cations. The associated [2 × 2] networks underwent time-dependent changes from the initial kinetic distribution to the final thermodynamic one, involving an orthogonal switch from one diagonal to the other diagonal of the square [2 × 2] network leading to a very large change in distribution. The DCL constituents could be switched from kinetic products (imines) to thermodynamic products (oximes or acylhydrazones) based on the reactivities of the components and the thermodynamic stabilities of the constituents without addition of any external effector, solely on the basis of the intrinsic properties of the self-contained system. Such processes were achieved for purely organic DCLs/CDNs as well as for inorganic ones containing two metal cations, the latter changing from the silver(I) complex of an imine (kinetic product) to the zinc(II) complex of a hydrazone (thermodynamic product). The results bear relationship to out-of-equilibrium systems concerning kinetic behavior in adaptive chemistry.
- He, Meixia,Lehn, Jean-Marie
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supporting information
p. 18560 - 18569
(2019/11/21)
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- Activation of primary amines by copper(i)-based lewis acid promoters in the solventless synthesis of secondary propargylamines
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Primary amines are activated by copper(I)-based Lewis acid promoters in an A 3 -coupling one-pot solventless reaction with aldehydes and phenylacetylene for the synthesis of secondary propargylamines. The reaction is promoted by a CuSO 4 /NaI system, a practical precursor of the in situ generated effective CuI/I 2 system, that worked well, but only in a restricted number of examples. Substitution of I 2 with CeCl 3 ·7H 2 O in a one-pot two-step reaction provided good yields and a wider applicability, with the added value given by a safer procedure.
- Cimarelli, Cristina,Navazio, Federica,Rossi, Federico V.,Del Bello, Fabio,Marcantoni, Enrico
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p. 2387 - 2396
(2019/05/27)
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- α-Acyl-α-diazoacetates in Transition-Metal-Free β-Lactam Synthesis
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Thermally promoted reaction of α-acyl-α-diazoacetates with imines has been investigated. The transformation, earlier reported predominantly under transition metal catalyzed conditions, delivers α-alkoxycarbonyl-substituted β-lactams with outstanding diastereoselectivity. DFT calculations performed in order to evaluate energetically feasible reaction pathways revealed the intermediacy of 1,3-oxazin-4-one intermediates hitherto never implicated in the Staudinger synthesis of β-lactams.
- Synofzik, Judith,Dar'In, Dmitry,Novikov, Mikhail S.,Kantin, Grigory,Bakulina, Olga,Krasavin, Mikhail
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p. 12101 - 12110
(2019/10/02)
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- Synthesis of polyheterocyclic pyrrolo[3,4-b]pyridin-5-ones via a one-pot (Ugi-3CR/aza diels-alder/N-acylation/aromatization/SN2) process. A suitable alternative towards novel Aza-analogues of falipamil
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We describe the one-pot synthesis of twenty polyheterocyclic pyrrolo[3,4-b]pyridin-5-ones via a cascade process (Ugi-3CR/aza Diels-Alder/N-acylation/aromatization) in 20 to 95% overall yields, as well as four pharmacologically promising analogues via an improved cascade process (Ugi-3CR/aza Diels-Alder/N-acylation/aromatization/SN2): two piperazine-linked pyrrolo[3,4b]pyridin-5-ones in 33 and 34%, and a couple of Falipamil aza-analogues in 30 and 35% overall yields. It is worth highlighting the good substrate scope found, because final products are furnished with alkyl, aryl, and heterocyclic substituents. The use of chain-ring tautomerizable isocyanides (as key reagents for the Ugi-type three component reaction) allowed for a rapid and efficient assembly of the polysubstituted oxindoles, which were used in situ toward the complex products, conferring features like robustness, sustainability, and the one-pot approach to this synthetic methodology.
- Zamudio-Medina, Angel,García-González, Ailyn N.,Herrera-Carrillo, Genesis K.,Zárate-Zárate, Daniel,Benavides-Macías, Adriana,Tamariz, Joaquín,Ibarra, Ilich A.,Islas-Jácome, Alejandro,González-Zamora, Eduardo
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- Selective aerobic oxidation of halides and amines with an inorganic-ligand supported zinc catalyst
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A practical, efficient and environmentally benign catalytic protocol for the oxidative cross-coupling reaction of halides with amines, oxidative self-coupling of amines and oxidation of halides was developed with inorganic-ligand supported ZnPOM (NH4)4[ZnMo6O18(OH)6] using molecular oxygen. This method mainly utilizes an inorganic polymolybdate ligand to support the Zn2+ ion, avoiding the use of complicated organic ligands.
- Wang, Jingjing,Zhai, Yongyan,Wang, Ying,Yu, Han,Zhao, Wenshu,Wei, Yongge
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p. 13323 - 13327
(2018/10/15)
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- Visible-Light-Driven Photocatalytic Oxidation of Organic Chlorides Using Air and an Inorganic-Ligand Supported Nickel-Catalyst Without Photosensitizers
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Engineering photoredox-triggered chemical transformation via visible light has been an emerging area in organic synthesis. However, most of the well-established photocatalysts are based upon either transition metal complexes involved with noble metals and organic ligands or photosensitive organic dyes, the development of pure inorganic molecular photocatalysts that could provide better stability and durability is greatly retarded. Herein we discover that the Anderson polyoxometalate (POM) Na4[NiMo6O18(OH)6] (1), which consists of pure inorganic framework built from a central NiII core supported by six MoVIO6 inorganic scaffold/ligands, can be used as a powerful photocatalyst. Upon irradiation with visible light (>400 nm), the compound can catalyze, in high efficiency, a wide range of reactions, including the oxidative cross-coupling reaction of chlorides with amines, as well as oxidation of chlorides using molecular oxygen, affording various imines, aldehydes, and ketones, respectively in high selectivity and good yields. Owing to the robust inorganic framework, this catalyst exhibits excellent stability during the catalysis and reusability with little loss of the catalytic activity, thus providing an alternative without use of complicated organic ligands and expensive noble metal-based photosensitizers.
- Yu, Han,Wang, Jingjing,Zhai, Yongyan,Zhang, Mengqi,Ru, Shi,Han, Sheng,Wei, Yongge
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p. 4274 - 4279
(2018/09/10)
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- MANGANESE BASED COMPLEXES AND USES THEREOF FOR HOMOGENEOUS CATALYSIS
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The present invention relates to novel manganese complexes and their use, inter alia, for homogeneous catalysis in (1) the preparation of imine by dehydrogenative coupling of an alcohol and amine; (2) C-C coupling in Michael addition reaction using nitriles as Michael donors; (3) dehydrogenative coupling of alcohols to give esters and hydrogen gas (4) hydrogenation of esters to form alcohols (including hydrogenation of cyclic esters (lactones) or cyclic di-esters (di- lactones), or polyesters); (5) hydrogenation of amides (including cyclic dipeptides, lactams, diamide, polypeptides and polyamides) to alcohols and amines (or diamine); (6) hydrogenation of organic carbonates (including polycarbonates) to alcohols or hydrogenation of carbamates (including polycarbamates) or urea derivatives to alcohols and amines; (7) dehydrogenation of secondary alcohols to ketones; (8) amidation of esters (i.e., synthesis of amides from esters and amines); (9) acylation of alcohols using esters; (10) coupling of alcohols with water and a base to form carboxylic acids; and (11) preparation of amino acids or their salts by coupling of amino alcohols with water and a base. (12) preparation of amides (including formamides, cyclic dipeptides, diamide, lactams, polypeptides and polyamides) by dehydrogenative coupling of alcohols and amines; (13) preparation of imides from diols.
- -
-
Paragraph 00277-00278
(2017/09/05)
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- Mechanochemical lignin-mediated strecker reaction
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A mechanochemical Strecker reaction involving a wide range of aldehydes (aromatic, heteroaromatic and aliphatic), amines, and KCN afforded a library of α-aminonitriles upon mechanical activation. This multicomponent process was efficiently activated by li
- Dabral, Saumya,Turberg, Mathias,Wanninger, Andrea,Bolm, Carsten,Hernández, José G.
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- Transition-Metal-Controlled Inorganic Ligand-Supported Non-Precious Metal Catalysts for the Aerobic Oxidation of Amines to Imines
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Most state-of-art transition-metal catalysts usually require organic ligands, which are essential for controlling the reactivity and selectivity of reactions catalyzed by transition metals. However, organic ligands often suffer from severe problems including cost, toxicity, air/moisture sensitivity, and being commercially unavailable. Herein, we show a simple, mild, and efficient aerobic oxidation procedure of amines using inorganic ligand-supported non-precious metal catalysts 1, (NH4)n[MMo6O18(OH)6] (M=Cu2+; Fe3+; Co3+; Ni2+; Zn2+, n=3 or 4), synthesized by a simple one-step method in water at 100 °C, demonstrating that the catalytic activity and selectivity can be significantly improved by changing the central metal atom. In the presence of these catalysts, the catalytic oxidation of primary and secondary amines, as well as the coupling of alcohols and amines, can smoothly proceed to afford various imines with O2 (1 atm) as the sole oxidant. In particular, the catalysts 1 have transition-metal ion core, and the planar arrangement of the six MoVI centers at their highest oxidation states around the central heterometal can greatly enhance the Lewis acidity of catalytically active sites, and also enable the electrons in the center to delocalize onto the six edge-sharing MO6 units, in the same way as ligands in traditional organometallic complexes. The versatility of this methodology maybe opens a path to catalytic oxidation through inorganic ligand-coordinated metal catalysis.
- Yu, Han,Zhai, Yongyan,Dai, Guoyong,Ru, Shi,Han, Sheng,Wei, Yongge
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supporting information
p. 13883 - 13887
(2017/10/13)
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- A metallopeptoid as an efficient bioinspired cooperative catalyst for the aerobic oxidative synthesis of imines
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Enzymatic catalysis is largely based on intramolecular cooperativity between a metal center and functional organic molecules located on one scaffold. Inspired by this concept we have designed the metallopeptoid trimer BT, which is a unique intramolecular cooperative oxidation catalyst incorporating two catalytic centers, phenanthroline-copper and TEMPO, as well as one non-catalytic benzyl group. Herein we explore the capability of BT to act as an efficient catalyst for the oxidative synthesis of imines, which are versatile intermediates in the fine chemicals and pharmaceutical industries. We demonstrate that BT, combined with CuI, can catalyze the production of benzyl, aryl, heteroaryl, allylic and aliphatic imines from various alcohols and amines with a turn-over-number up to 45 times higher than this achieved when phenanthroline, copper and TEMPO are mixed in solution. Moreover, in low catalyst(s) loading, BT enables transformations that are not possible when a mixture of the individual catalysts is employed.
- Chandra Mohan, Darapanani,Sadhukha, Arghya,Maayan, Galia
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p. 139 - 144
(2017/10/16)
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- Dual Heterogeneous Catalyst Pd-Au@Mn(II)-MOF for One-Pot Tandem Synthesis of Imines from Alcohols and Amines
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A new Mn(II) metal-organic framework (MOF) 1 was synthesized by the combination of 4,4,4-trifluoro-1-(4-(pyridin-4-yl)phenyl)butane-1,3-dione (L) and Mn(OAc)2 in solution. 1 features a threefold-interpenetrating NbO net containing honeycomb-like channels, in which the opposite Mn(II)···Mn(II) distance is 23.5075(10) ?. Furthermore, 1 can be an ideal platform to support Pd-Au bimetallic alloy nanoparticles to generate a composite catalytic system of Pd-Au@Mn(II)-MOF (2). 2 can be a highly active bifunctional heterogeneous catalyst for the one-pot tandem synthesis of imines from benzyl alcohols and anilines and from benzyl alcohols and benzylamines.
- Chen, Gong-Jun,Ma, Hui-Chao,Xin, Wen-Ling,Li, Xiao-Bo,Jin, Fa-Zheng,Wang, Jing-Si,Liu, Ming-Yang,Dong, Yu-Bin
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supporting information
p. 654 - 660
(2017/01/13)
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- Aerobic oxidative coupling of alcohols and amines towards imine formation by a dicopper(I,I) catalyst
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A dicopper(I,I) complex [Cu2(L1) (Cl)2] (1), bearing a Cu2Cl2 core spanned by a naphthyridine–diimine ligand is synthesized by the treatment of CuCl with 2,7–bis(N–mesitylmethylimino)–1,8–naphthyridine (L1). The catalytic efficacy of 1 is assessed for aerobic oxidative synthesis of imines from alcohols and amines. The title complex is found to be an excellent catalyst for a wide variety of alcohols and amines. Kinetic experiments revealed the involvement of both copper ions in the aerobic oxidation process. The general utility of naphthyridine based ligands to favour a possible bimetallic pathway for a catalytic reaction is demonstrated here.
- Dutta, Indranil,De, Subhabrata,Yadav, Sudhir,Mondol, Ranajit,Bera, Jitendra K.
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p. 117 - 124
(2017/09/30)
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- Manganese-Catalyzed Environmentally Benign Dehydrogenative Coupling of Alcohols and Amines to Form Aldimines and H2: A Catalytic and Mechanistic Study
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The catalytic dehydrogenative coupling of alcohols and amines to form aldimines represents an environmentally benign methodology in organic chemistry. This has been accomplished in recent years mainly with precious-metal-based catalysts. We present the dehydrogenative coupling of alcohols and amines to form imines and H2 that is catalyzed, for the first time, by a complex of the earth-abundant Mn. Detailed mechanistic study was carried out with the aid of NMR spectroscopy, intermediate isolation, and X-ray analysis.
- Mukherjee, Arup,Nerush, Alexander,Leitus, Gregory,Shimon, Linda J. W.,Ben David, Yehoshoa,Espinosa Jalapa, Noel Angel,Milstein, David
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supporting information
p. 4298 - 4301
(2016/05/09)
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- Concise synthesis of spergualin-inspired molecules with broad-spectrum antibiotic activity
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There is a growing need to identify new, broad-spectrum antibiotics. The natural product spergualin was previously shown to have promising anti-bacterial activity and a privileged structure, but its challenging synthesis had limited further exploration. For example, syntheses of spergualin and its analogs have been reported in approximately 10 linear steps, with overall yields between 0.3 and 18%. Using the Ugi multi-component reaction, we assembled spergualin-inspired molecules in a single step, dramatically improving the overall yield (20% to 96%). Using this strategy, we generated 43 new analogs and tested them for anti-bacterial activity against two Gram-negative and four Gram-positive strains. We found that the most potent analogue, compound 6, had MIC values between 4 and 32 μg mL-1 against the six strains, which is a significant improvement on spergualin (MIC ~ 6.25 to 50 μg mL-1). These studies provide a concise route to a broad-spectrum antibiotic with a novel chemical scaffold. This journal is
- Assimon, Victoria A.,Shao, Hao,Garneau-Tsodikova, Sylvie,Gestwicki, Jason E.
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p. 912 - 918
(2015/05/27)
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- Lanthanide coordination polymer constructed from 2,2′-bipyridyl-4,4′-dicarboxylic acid: Structure, catalysis and fluorescence
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Two new isostructural lanthanide coordination polymers (Ln-CPs) [Ln2(bpdc)3(DMF)2] (Ln = Tb for 1, Eu for 2) with two kinds of one-dimensional channels along the a axis, were synthesized by 2,2′-bipyridyl-4,4′-dicarboxylic acid (H2bpdc) under solvothermal conditions. With exposed Lewis acid Ln3+ centers, 1 as a heterogeneous catalyst shows good catalytic reactivity and selectivity for the Strecker reaction affording medium to excellent conversion yields. Luminescent studies illustrate that 1 and 2 show intensive green and red luminescence triggered by efficient antenna effect of ligands under UV light, respectively. Moreover, 1 exhibits sensitive fluorescent response to Cu2+ in DMF solution.
- Wang, Shengyan,Xu, Jianing,Zheng, Jifu,Chen, Xiaodong,Shan, Liang,Gao, Lijuan,Wang, Li,Yu, Miao,Fan, Yong
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supporting information
p. 81 - 86
(2015/09/15)
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- Selective aerobic oxidation of alcohols to aldehydes, carboxylic acids, and imines catalyzed by a Ag-NHC complex
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Silver NHC catalysts have been developed for the selective oxidation of alcohols to aldehydes or carboxylic acids in the presence of BnMe3NOH or KOH under dry air. The aerobic oxidation conditions are mild, and the yield is excellent. Further tandem catalysis enables the one-pot synthesis of imines in excellent yield. Only 0.1 mol % of the catalyst is required.
- Han, Lei,Xing, Ping,Jiang, Biao
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supporting information
p. 3428 - 3431
(2014/07/21)
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- Substituted 4-Oxo-1,2,3,4-tetrahydroquinoline-3-carboxylic esters by a tandem imine addition-SNAr reaction
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A tandem imine addition-SNAr annulation reaction has been developed as a new approach to the synthesis of 4-oxo-1,2,3,4- tetrahydroquinoline-3-carboxylic esters. A series of these structures has been generated by reacting selected imines with tert-butyl 2-fluoro-5- nitrobenzoylacetate. Structural variations in the final products are accomplished by changing the substituents on the imine and the alkyl group of the ester. The title compounds are isolated as their enols in 55-97% yield without the need for added base or catalysts. The synthesis of the starting materials as well as mechanistic studies and further synthetic conversions of the products are presented.
- Bunce, Richard A.,Schammerhorn, James E.,Sigle, Jessica
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p. 373 - 380
(2013/06/04)
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- Synthesis of substituted oxazoles from N-benzyl propargyl amines and acid chlorides
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The reaction between N-benzylpropargylamines and acid chlorides at elevated temperatures provides efficient, direct access to a variety of di- and tri-substituted oxazoles. The versatility of this reaction is explored and 21 examples are demonstrated. The usefulness of the methodology is showcased through the short and efficient formal syntheses of medicinally relevant drugs aleglitazar and romazarit. The reaction between N-benzylpropargylamines and acid chlorides at elevated temperatures gives oxazoles in up to 99 % yield. Twenty-one examples are demonstrated varying the substitution at all positions of the heterocycle. Copyright
- Wachenfeldt, Henrik V.,Paulsen, Filip,Sundin, Anders,Strand, Daniel
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supporting information
p. 4578 - 4585
(2013/07/26)
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- Synthesis of α, α-dideutero-β-amino esters
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A straight forward entry to α, α-dideutero-β-amino esters starting from the corresponding imines and deuterated acetonitrile has been developed involving a two-step process.
- Chandrasekhar,Pendke, Mrunal,Muththe, Chandrashekar,Akondi, Srirama Murthy,Mainkar, Prathama S.
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p. 1292 - 1295
(2012/03/27)
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- Iridium-catalyzed reduction of secondary amides to secondary amines and imines by diethylsilane
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Catalytic reduction of secondary amides to imines and secondary amines has been achieved using readily available iridium catalysts such as [Ir(COE) 2Cl]2 with diethylsilane as reductant. The stepwise reduction to secondary amine proceeds through an imine intermediate that can be isolated when only 2 equiv of silane is used. This system requires low catalyst loading and shows high efficiency (up to 1000 turnovers at room temperature with 99% conversion have been attained) and an appreciable level of functional group tolerance.
- Cheng, Chen,Brookhart, Maurice
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supporting information; experimental part
p. 11304 - 11307
(2012/09/05)
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- A remarkable titanium-catalyzed asymmetric strecker reaction using hydrogen cyanide at room temperature
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Close to perfect enantioselectivity (up to 98% ee) is obtained for the formation of amino nitrites using hydrogen cyanide (HCN) as the cyanide source at room temperature for the first time. In an operationally simple process, the catalyst generated from a partially hydrolyzed titanium alkoxide (PHTA) and (S)-N-salicyl-ss-amino alcohol ligand, catalyzes the cyanation of imines in a short reaction time.
- Ramalingam, Balamurugan,Seayad, Abdul Majeed,Chuanzhao, Li,Garland, Marc,Yoshinaga, Kazuhiko,Wadamoto, Manabu,Nagata, Takushi,Chai, Christina L. L.
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supporting information; experimental part
p. 2153 - 2158
(2010/11/04)
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- Asymmetric addition of trimethylsilylcyanide to N-benzylimines catalyzed by recyclable chiral dimeric V(V) salen complex
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Chiral dimeric vanadium (V) salen complex (10 mol%) derived from 5,5-Methylene di-[(S,S)-{N-(3-tert-butyl salicylidine)-N′-(3′,5′-di-tert-butyl salicylidene)]-1,2-cyclohexanediamine] with vanadyl suphate followed by auto oxidation was used as efficient catalyst for enantioselective Strecker reaction of N-benzylimines with TMSCN at -30 °C. Excellent yield (92%) of α-aminonitrile and high chiral induction was achieved (ee up to 94%) in case of 2-methoxy substituted N-benzylimines in 10 h. The catalytic system worked well up to four cycles with retention of enantioselectivity.
- Khan, Noor-ul H.,Saravanan,Kureshy, Rukhsana I.,Abdi, Sayed H.R.,Sadhukhan, Arghya,Bajaj, Hari C.
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experimental part
p. 1133 - 1137
(2010/06/13)
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- Structural-activity relationship study of highly-functionalized imidazolines as potent inhibitors of nuclear transcription factor-κB mediated IL-6 production
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We herein describe the synthesis and anti-inflammatory properties of a small library of imidazoline-based NF-κB inhibitors. The structure-activity relationship of various substituents on an imidazoline core structure was evaluated for the ability to inhibit NF-κB mediated IL-6 production. Optimization of the scaffolds was pursued by correlating luciferase-based NF-κB reporter assays with inhibition of IL-6 production in IL-1β stimulated human blood. Several derivatives were found to inhibit NF-κB mediated IL-6 production in the nanomolar range in IL-1β stimulated human blood.
- Kahlon, Daljinder K.,Lansdell, Theresa A.,Fisk, Jason S.,Tepe, Jetze J.
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experimental part
p. 3093 - 3103
(2009/10/02)
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- Synthesis of a natural product-inspired eight-membered ring lactam library via ring-closing metathesis
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We have prepared a novel speculative eight-membered lactam demonstration library based on the skeletal structure of the potent antitumor marine natural product octalactin A. The basic scaffold was readily constructed in a convergent fashion via ring-closing metathesis chemistry from the corresponding diene amides. A cursory examination of the biological properties of the library validates the relevance and significance of these structures.
- Brown, Neil,Xie, Baohan,Markina, Nataliya,VanderVelde, David,Perchellet, Jean-Pierre H.,Perchellet, Elisabeth M.,Crow, Kyle R.,Buszek, Keith R.
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scheme or table
p. 4876 - 4879
(2009/05/30)
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- Synthesis of 2-alkyl-1-aryl-1,2-dihydrochromeno[2,3-c]pyrrole-3,9-dione derivatives
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A preparative procedure for the synthesis of 2-alkyl-1-aryl-1,2- dihydrochromeno[2,3-c]pyrrole-3,9-diones from methyl 4-(o-hydroxyphenyl)-2,4- dioxobutanoate, aromatic aldehyde, and aliphatic amine is described.
- Vydzhak,Panchishin, S. Ya.
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experimental part
p. 2391 - 2397
(2009/05/30)
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- ORGANIC PHOSPHORUS COMPOUNDS 94 PREPARATION, PHYSICAL AND BIOLOGICAL PROPERTIES OF AMINO-ARYLMETHYLPHOSPHONIC- AND -PHOSPHONOUS ACIDS
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The preparation, physical and spectroscopic properties of amino-arylmethylphosphonic- and -phosphonous acids, the phosphorus analogues of phenylglycine, are described.It is shown that several of the compounds prepared exhibit antifungal activity at 200 ppm.Thus 1e, 1f, 1g and 1h showed activity against Erysiphe (barley), 2a against Puccinia (wheat) and 6a against Botrytis (apple).Of particular interest is the high gameticidal activity of 3a in the greenhouse.
- Maier, Ludwig,Diel, Peter J.
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- Cycloaddition of (N-Alkyl-N-phenylamino)ketene with Imines
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(N-Alkyl-N-phenylamino)ketenes were prepared in the presence of various imines, and a cycloaddition reaction occurred to yield 3-(N-alkyl-N-phenylamino)-2-azetidinones.The size and electronic nature of the imine substituents were varied in order to probe those factors that influence the stereochemistry of the cycloaddition.The stereochemistry of the 2-azetidinone was determined by the substitution pattern of the imines.In general, the stereochemistry of the 2-azetidinone products are significantly influenced by the bulk of the N substituent on the imine.These results are discussed in terms of a two-step zwitterionic intermediate.
- Brady, William T.,Dad, Mohammad M.
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p. 6118 - 6122
(2007/10/02)
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