- Development of 7-membered N-heterocyclic carbene ligands for transition metals
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We recently reported the first example of a seven-membered N-heterocyclic carbene (NHC) ligand for transition metals. These ligands are attractive because the heterocyclic framework, derived from 2,2′-diaminobiphenyl, exhibits a torsional twist that results in a chiral, C2-symmetric structure. The present report outlines the synthetic efforts that led to the development of these ligands together with the synthesis and structural characterization of metal complexes bearing seven-membered NHCs as ancillary ligands. The identity of nitrogen substituent, neopentyl versus 2-adamantyl, influences the synthetic accessibility and stability of the seven-membered amidinium salts and the NHC-metal complexes obtained via in situ deprotonation/metallation. Computational analysis of the seven-membered ring structures reveals the Hückel antiaromatic 8π electron system achieves significant M?bius aromatic stabilization upon undergoing torsional distortion of the heterocyclic ring.
- Scarborough, Christopher C.,Popp, Brian V.,Guzei, Ilia A.,Stahl, Shannon S.
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- Selective formation of benzo[c]cinnoline by photocatalytic reduction of 2,2′-dinitrobiphenyl using TiO2 and under UV light irradiation
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Photocatalytic reduction of 25 μmol 2,2′-dinitrobiphenyl in 50% aqueous iso-propanol and 50 mg P25-TiO2 under an argon atmosphere and 20 h UV light irradiation selectively produced 23.8 μmol of benzo[c]cinnoline (95%), and 2,2′-biphenyldiamine (5%) whose amount gradually increased with the irradiation time beyond 20-24 h due to further reduction of benzo[c]cinnoline. This journal is
- Kaur, Jaspreet,Pal, Bonamali
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- Formation of 1,10-Disubstituted Benzo[c]cinnolines. Synthesis and Molecular Structure of 1-Amino-10-propylthiobenzo[c]cinnoline and Cyclization to 4-Propylcinnolino[5,4,3][c,d,e][1,2]benzothiazine
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The first 1,10-heterodisubstituted benzo[c]cinnoline derivative 1 was prepared from the trinitrobiphenyl 2. Investigation of the mechanism of ring closure in 2, 5, and 8 revealed a complex reduction-oxidation-cyclization sequence. The mechanism is discussed in light of the stereoelectronic demands of the substituent functionalities. Benzo[c]cinnoline derivative 1 [C15H15N3S, monoclinic, P21/c: a = 7.4063(3) A, b = 10.3739(5) A, c = 16.7642(8) A, β = 91.816(1)°, Z = 4] and its 5-N-oxide 7(N5) [C18H18N3OS, triclinic, P1: a = 8.1510(7) A, b = 8.6106(7) A, c = 12.102(1) A, α = 86.262(1)°, β = 83.364(1)°, γ = 74.711(1)°, Z = 4] were structurally characterized and showed a significant helical distortion of the heterocyclic ring. Oxidation of 1 with NCS or triamine 12 with PhI(OAc)2 led to a new heterocyclic ring system, ylide 13. Both benzo[c]cinnoline 1 and ylide 13 were characterized spectroscopically and the absorption spectra were correlated with the results of ZINDO calculations.
- Benin, Vladimir,Kaszynski, Piotr,Pink, Maren,Young Jr., Victor G.
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- Studies of Consecutive Reactions of Quinones in a Reversed Geometry Mass Spectrometer
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Consecutive reactions involving the ejection of molecules of carbon monoxide from quinone systems have been studied.Using a reversed geometry double focusing mass spectrometer, the individual steps of a consecutive reaction may be separated into different field free regions.The structure of ions formed in the ion source may be compared with those formed from the fragmentation of metastable ions in a field free region by studying differences in the pattern of translational energies released when they break.In the case of anthraquinone it is found that two structures exist for the +. ion.Critical energy measurements strengthen this argument.Furthermore, 18O labelling has been used to distinguish between the loss of carbon monoxide from different positions on the molecular ion of 1-hydroxyanthraquinone.
- Proctor, C. J.,Kralj, B.,Larka, E. A.,Porter, C. J.,Maquestiau, A.,Beynon, J. H.
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- Macrocyclic [Cu(I/II)(bite)](+/2+) (bite = biphenyldiimino dithioether): An example of fully-gated electron transfer and its biological relevance
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Template condensation of 2,2'-diaminobiphenyl, 1,4-bis(2-formylphenyl)-1,4-dithiabutane, and copper(II) tetrafluoroborate yields the new macrocyclic compound [Cu(I)(bite)l(BF4) (bite = biphenyldiimino dithioether). [Cu(I)(bite)]BF4 c
- Flanagan, Scott,Dong, Jun,Haller, Kenneth,Wang, Shengke,Scheidt, W. Robert,Scott, Robert A.,Webb, Thomas R.,Stanbury, David M.,Wilson, Lon J.
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- Synthesis and Preliminary Evaluation of 68Ga-NOTA-Biphenyl-c(RGDyK) for the Quantification of Integrin αvβ3
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Arginine-glycine-aspartate (RGD) peptide binds to the integrin αvβ3, which plays a crucial role in tumor angiogenesis and metastasis. Previously developed 68Ga-labeled cyclic RGD peptides are rapidly excreted from the circulatory system. In the present study, we developed a 68Ga-labeled cyclic RGD peptide with a biphenyl group between the chelator and RGD peptide, i.e., 68Ga-NOTA-biphenyl-c(RGDyK). Then, we performed the comparison with the reference compound, i.e., 68Ga-NOTA-c(RGDyK). 68Ga-NOTA-biphenyl-c(RGDyK) was 37% less hydrophilic than 68Ga-NOTA-c(RGDyK). For positron emission tomography imaging, 68Ga-NOTA-biphenyl-c(RGDyK) had a longer retention time and showed a higher signal-to-noise ratio in tumors than 68Ga-NOTA-c(RGDyK). However, the biphenyl-radiopeptide displayed the relatively high non-specific binding. From these perspectives, incorporation of the biphenyl group to the RGD generates pros and cons.
- Shin, Un Chul,Jung, Ki-Hye,Park, Ji-Ae,Lee, Ji Woong,Kim, Jung Young,Seo, Jongbum,Lee, Kyo Chul,Choi, Jae Yong
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- Biphenyl Bis(amino alcohol) Oxalamide Gelators: Complex Gelation Involving Coupled Equilibria, Central-to-Axial Chirality Transfer, Diastereoisomer Interconversion, and Self-Sorting
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Chiral gelators 3 and 4, with two valinol- or leucinol-oxalamido arms attached to the 2,2′-positions of the proatropisomeric biphenyl group, were prepared, and their gels were studied. Compound (R,R)-3 in the solution and gel states forms a mixture of major [(R,aR,R)-3] and minor [(R,aS,R)-3] diastereomers due to central-to-axial chirality transfer. 1H NMR studies of its toluene gel provide evidence of diastereomer interconversion and self-sorting, which results in exclusive incorporation of (R,aR,R)-3 into the gel network. Gels formed in the 10-3 M concentration range show an irregular Tg/concentration dependence, which is in contrast to those formed in the 10-2 M concentration range. The peculiar properties of the former gels may be explained by kinetic effects due to the presence of coupled equilibria comprising diastereomer interconversion and (R,aR,R)-3 self-assembly where the rate of gelation becomes dependent on the rate of formation of the gelling (R,aR,R)-3 from the nongelling (R,aS,R)-3.
- Portada, Tomislav,Mol?anov, Kre?imir,?ijakovic Vuji?ic, Nata?a,?inic, Mladen
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- Poly(3,6-silafluorene-co-2,7-fluorene)-based high-efficiency and color-pure blue light-emitting polymers with extremely narrow band-width and high spectral stability
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A new series of copolymers (PSiFF) based on 3,6-silafluorene and 2,7-fluorene were synthesized via the Suzuki polycondensation. The influences of the 3,6-silafluorene content in the copolymers on the thermal, photophysical, electroluminescence and electrochemical properties were investigated. The incorporation of 3,6-silafluorene into the polyfluorene main chain not only suppressed the long-wavelength emission but significantly improved the efficiency and color purity of the copolymer-based devices. Both fluorene and 3,6-silafluorene took part in π-conjugation of the main chain and the electroluminescence spectra were remarkably blue-shifted with increasing wide bandgap 3,6-silafluorene content. The device based on PSiFF90 with the configuration of ITO/PEDOT: PSS/PVK/polymer/Ba/Al showed a quantum efficiency of 3.34% and a luminous efficiency of 2.02 cd A-1 at a brightness of 326 cd m-2 with CIE 1931 chromaticity coordinates of (0.16, 0.07), which almost match the NTSC standard blue pixel coordinates of (0.14, 0.08). Moreover, the incorporation of 3,6-silafluorene into the polyfluorene main chain significantly improved the spectral stability at annealing. The results indicate poly(3,6-silafluorene-co-2,7-fluorene) could be a promising candidate for blue-emitting polymers of high efficiency and good color purity. The Royal Society of Chemistry 2006.
- Wang, Ergang,Li, Chun,Mo, Yueqi,Zhang, Yong,Ma, Gang,Shi, Wei,Peng, Junbiao,Yang, Wei,Cao, Yong
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- PdII complexes possessing a seven-membered N-heterocyclic carbene ligand
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(Chemical Equation Presented) Carbenes with a twist: A seven-membered N-heterocyclic carbene (NHC) ligand is prepared from an amidinium precursor, derived from 2,2′-dinitrobiphenyl, and yields the NHC-PdII complex [PdCl(allyl)-(NHC)] (see scheme). This carbene framework exhibits a tortional twist that results in axial symmetry. This ligand class can be readily modified and is attractive for future application in asymmetric catalysis.
- Scarborough, Christopher C.,Grady, Michael J. W.,Guzei, Ilia A.,Gandhi, Bhavesh A.,Bunel, Emilio E.,Stahl, Shannon S.
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- Gd complexes of macrocyclic diethylenetriaminepentaacetic acid (DTPA) biphenyl-2,2′-bisamides as strong blood-pool magnetic resonance imaging contrast agents
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We report the synthesis of macrocyclic DTPA conjugates of 2,2′-diaminobiphenyl and their Gd complexes of the type [Gd(L)(H 2O)]?xH2O (2a,b; L = 1a,b) for use as new MRI blood-pool contrast agents (MRI BPCAs). Pharmacokinetic inertnes
- Jung, Ki-Hye,Kim, Hee-Kyung,Lee, Gang Ho,Kang, Duk-Sik,Park, Ji-Ae,Kim, Kyeong Min,Chang, Yongmin,Kim, Tae-Jeong
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- Highly Chemoselective Access to 2,2-Diaminobiaryls via Ni-Catalyzed Protecting-Group-Free Coupling of 2-Haloanilines
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The development of strategies to access 2,2-diaminobiaryl derivatives via a transition-metal-catalyzed coupling reaction from protecting-group-free starting materials is a challenging task to accomplish, owing to the easy occurrence of undesired side reactions. The exploitation of Ni-catalyzed direct homocoupling of unprotected 2-haloaniline analogues to produce 2,2-diaminobiaryls with a readily available and inexpensive bipyridine ligand has been described. This approach was highlighted by its high chemoselectivity, broad substrate scope, and functional group compatibility. The mechanistic and calculation studies indicated that Ni(0), Ni(I), Ni(II), and Ni(III) species might be involved in the catalytic cycle.
- Long, Cheng-Yu,Ni, Shao-Fei,Su, Min-Hui,Wang, Xue-Qiang,Tan, Weihong
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- Design and synthesis of novel ROR inverse agonists with a dibenzosilole scaffold as a hydrophobic core structure
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Abstract Molecular structure calculations indicated that the dibenzosilole skeleton could be well superposed on phenanthridinone, which is a structural component of ligands of retinoic acid receptor-related orphan receptors (RORs). Therefore, we designed,
- Toyama, Hirozumi,Nakamura, Masaharu,Hashimoto, Yuichi,Fujii, Shinya
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- Asymmetric activation of the tropos biphenyldiamidophosphite moiety: Synthesis and complexation to rhodium of a deoxycholic acid derived diamidophosphite
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A tropos deoxcholic acid derived diamidophosphite was synthesised starting from deoxycholic acid and N,N′-dimethyl-2,2′-diamino-1,1′biphenyl and its stereodinamic characteristics were assessed by VT-NMR spectroscopy. The capability of the diamidophosphite
- Iannucci, Grazia,Iuliano, Anna
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- Synthesis, characterization, and X-ray crystal structures of bis [N-(3,3-diphenylallylidene)quinolin-8-amine-κV,κN 8]copper(1+) tetraphenylborate(1-)
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Two new ligands, N-(3,3-diphenylallylidene)quinolin-8-amine (dpa-qa; L 1) and N,N′-bis-(3,3-diphenylallylidene)[1,1′-biphenyl]- 2,2′-diamine (bdpa-bda; L2), and their corresponding copper(I) complexes, [Cu(dpa-qa)2]BPhsub
- Amirnasr, Mehdi,Kickelbick, Guido,Dehghanpour, Saeed
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- Reduction of 2,2′-dinitrobiphenyl with hydrazine hydrate catalyzed by Pd/C: Cobalt(II), zinc(II) and mercury(II) complexes with benzo[c]cinnoline and N2,N2′-bis(3-phenylallylidene)biphenyl-2,2′- diamine
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The catalytic reduction of 2,2′-dinitrobiphenyl with different molar ratios of hydrazine hydrate resulted in two different compounds; benzo[c]cinnoline (L1) and 2,2′-diaminobiphenyl. N 2,N2′-bis(3-phenylallylidene)biphenyl-2,2′- diamine (L2) has been synthesized by the condensation of 2,2′-diaminobiphenyl with cinnamaldehyde. Complexes of the type ML 12X2 and ML2X2 (M = Co(II), Zn(II); X = Cl, Br or I and Hg(L2)Cl2) have been synthesized and characterized by CHN analysis, IR, 1H NMR and UV-Vis spectroscopy. The crystal structures of Co(L1)2Cl 2, Zn(L1)2Br2 and Hg(L 2)Cl2 were determined using single crystal X-ray diffraction. In these three complexes, the coordination polyhedron about the central metal ion is best described as a distorted tetrahedron. The Co(L 1)2Cl2, and Zn(L1) 2Br2 complexes exhibit supramolecular structures resulting from π-π stacking of the benzo[c]cinnoline ligands. The diimine ligand, L2, in the Hg(L2)Cl2 complex coordinates to Hg(II) through the two nitrogens of the two phenyl rings to form a seven-membered metallocycle. Furthermore, the ligand prefers a trans-trans arrangement in the Hg(L2)Cl2 complex.
- Dehghanpour, Saeed,Afshariazar, Farzaneh,Assoud, Jalil
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- Reductive Coupling of Aryl Halides via C—H Activation of Indene
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This paper describes the first case of a reductive coupling reaction with indene, a non-heteroatom olefin used as a reducing agent. The scope of the substrate is wide. The homo-coupling, cross-coupling, and synthesis of 12 and 14-membered rings were realized. The control experiment, indene-product curve and density functional theory calculations showed that the η3-palladium indene intermediate was formed by C—H activation in the presence of cesium carbonate. We speculate that the final product was obtained through a Pd (IV) intermediate or aryl ligand exchange. In addition, we excluded the formation of palladium anion (Pd(0)?) intermediates.
- Zhang, Bo-Sheng,Yang, Ying-Hui,Wang, Fan,Gou, Xue-Ya,Wang, Xi-Cun,Liang, Yong-Min,Li, Yuke,Quan, Zheng-Jun
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p. 1573 - 1579
(2021/05/28)
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- The Reaction Mechanism Between Tetraarylammonium Salts and Hydroxide
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The mechanism of the reaction between tetraaryl ammonium salts and hydroxide is studied experimentally for different N,N-diaryl carbazolium salts. The N,N-diarylcarbazolium salts are designed, synthesized, characterized, and reacted with hydroxide under different conditions. The products of the reactions were directly characterized or isolated when possible and, using different substituents, the reaction mechanisms were compared. An unexpected H/D exchange observed in these salts helped to discard the classical SNAr mechanisms, supporting instead a radical mechanism initiated by a single-electron transfer from the hydroxide. By understanding the preferred reaction pathways, better quaternary ammonium salts can be designed to withstand aggressive alkaline environments, critical for many practical applications such as anion-exchange membrane fuel cells.
- Aharonovich, Sinai,Dekel, Dario R.,Diesendruck, Charles E.,Gjineci, Nansi,Willdorf-Cohen, Sapir
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- Intermolecular coupling and intramolecular cyclization of aryl nitriles on Au(111)
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The on-surface dimerization reaction of an organic nitrile on Au(111) is reported. The formation of the product, which contains five newly formed σ-bonds and a diazapyrene core structure, was investigated and characterized by scanning tunneling microscopy. Experimental and computational studies of reference compounds support our findings.
- Klaasen, Henning,Liu, Lacheng,Gao, Hong-Ying,Viergutz, Lena,Held, Philipp A.,Knecht, Tobias,Meng, Xiangzhi,B?rner, Melanie C.,Barton, Dennis,Amirjalayer, Saeed,Neugebauer, Johannes,Studer, Armido,Fuchs, Harald
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supporting information
p. 11611 - 11614
(2019/10/02)
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- General rhodium-catalyzed oxidative cross-coupling reactions between anilines: Synthesis of unsymmetrical 2,2′-diaminobiaryls
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Described herein is a dual chelation-assisted RhCl3-catalyzed oxidative C-H/C-H cross-coupling reaction of aniline derivatives. The highlight of this methodology is the chemo- and regioselective cross-coupling between electronically similar substrates, which represents a highly challenging task in oxidative Ar-H/Ar-H cross-coupling reactions. Furthermore, this Cp?-free catalytic reaction tolerates a range of functional groups and requires only a low molar ratio of coupling partners. These features expedite the synthesis of unsymmetrical 2,2′-diaminobiaryls.
- Shi, Yang,Liu, Jiahui,Yang, Yudong,You, Jingsong
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p. 5475 - 5478
(2019/05/16)
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- Biphenyl-containing RGD derivatives, a process for the preparation thereof and a radiopharmaceuticals comprising the same
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According to one aspect of the present invention, provided is a compound represented by chemical formula I, having a structure in which a tumor-selective arginylglycylaspartic acid (Arg-Gly-Asp, RGD) peptide and a ligand for radioactive isotope labeling are each covalently bonded to amines on both sides of 2,2andprime;-diaminobiphenyl. Moreover, provided are a compound which is for radiopharmaceutical products and to which a radioisotope is bound to the compound, a method for producing the compound for radiopharmaceutical products, and a radiopharmaceutical product containing the compound for radiopharmaceutical products.(AA) RGD peptides(BB) LigandCOPYRIGHT KIPO 2018
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Paragraph 0069; 0099-0102
(2019/02/02)
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- An Effective Synthesis of N, N -Diphenyl Carbazolium Salts
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Tetraaryl ammonium salts are a synthetic challenge, since there is no general method for the arylation of triaryl amines. Contrary to other quaternary ammonium salts, tetraaryl ammonium salts should be very chemically stable. The ipso carbons are not very
- Aharonovich, Sinai,Gjineci, Nansi,Dekel, Dario R.,Diesendruck, Charles E.
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supporting information
p. 1314 - 1318
(2017/12/28)
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- NITROGEN-CONTAINING HETEROCYCLIC COMPOUNDS FOR ORGANIC LIGHT EMITTING DEVICES
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A compound of formula (I), a material for an organic electroluminescence device comprising at least one compound of formula (I); an organic electroluminescence device which comprises an organic thin film layer between a cathode and an anode, wherein the organic thin film layer comprises one or more layers and comprises a light emitting layer, and at least one layer of the organic thin film layer comprises at least one compound of formula (I); an electronic equipment comprising the organic electroluminescence device; and a process for preparing the compound of formula (I).
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Paragraph 0230; 0231
(2018/07/29)
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- Twisted Cycloalkynes and Remote Activation of “Click” Reactivity
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The “twisted and bent” cyclodecyne structural motif, intertwined with dormant electronic effects, opens a conceptually powerful way to control “click” reactivity. The endocyclic heteroatoms of cyclodecynes provide dual electronic activation via hyperconju
- Harris, Trevor,Gomes, Gabriel dos Passos,Ayad, Suliman,Clark, Ronald J.,Lobodin, Vladislav V.,Tuscan, Megan,Hanson, Kenneth,Alabugin, Igor V.
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supporting information
p. 629 - 640
(2017/12/07)
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- Visible-Light-Induced Synthesis of Carbazoles by in Situ Formation of Photosensitizing Intermediate
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A visible-light-induced synthesis of N-H carbazoles from easily accessible 2,2′-diaminobiaryls in the absence of any external photosensitizer is reported. The process only requires tBuONO and natural resources, visible light, and molecular oxygen for the synthesis of N-H carbazoles. Experimental and computational studies support that the in situ formation of a visible-light-absorbing photosensitizing intermediate, benzocinnoline N-imide, is responsible for the activation of triplet molecular oxygen to singlet oxygen that, in turn, promotes the synthesis of carbazole.
- Chatterjee, Tanmay,Roh, Geum-Bee,Shoaib, Mahbubul Alam,Suhl, Chang-Heon,Kim, Jun Soo,Cho, Cheon-Gyu,Cho, Eun Jin
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supporting information
p. 1906 - 1909
(2017/04/11)
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- Organocatalytic stereoselective synthesis of 3-alkyl-3-hydroxy-2-oxindoles catalyzed by novel water-compatible axially unfixed biaryl-based bifunctional organocatalysts
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In this work, six novel axially unfixed biaryl-based water-compatible bifunctional organocatalysts were designed and synthesized for the organocatalytic access to a variety of 3-alkyl-3-hydroxy-2-oxindole derivatives via aldol reactions in water. Organoca
- Zhao, Hongwu,Meng, Wei,Yang, Zhao,Tian, Ting,Sheng, Zhihui,Li, Hailong,Song, Xiuqing,Zhang, Yutong,Yang, Sen,Li, Bo
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p. 417 - 428
(2014/06/10)
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- Novel axially unfixed biaryl-based water-compatible organocatalysts: Design, synthesis and their asymmetric catalysis in direct aldol reactions in water
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A family of novel axially unfixed biaryl-based, water-compatible bifunctional organocatalysts were designed and synthesized for asymmetric catalytic direct aldol reactions in water. These organocatalysts are comprised of prolinamide, aromatic sulfonamide and biaryl motifs. Under the optimal reaction conditions, one organocatalyst in particular delivered excellent stereocontrol (up to 99% ee and 99:1 dr) in direct aldol reactions of cyclohexanone with a variety of aromatic aldehydes in water. Georg Thieme Verlag Stuttgart, New York.
- Zhao, Hong-Wu,Yue, Yuan-Yuan,Li, Hai-Long,Song, Xiu-Qing,Sheng, Zhi-Hui,Yang, Zhao,Meng, Wei,Yang, Ze
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supporting information
p. 2160 - 2164
(2013/10/22)
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- Copper catalyzed Gomberg-Buchmann-Hey reaction using aryldiazonium tosylate
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Copper catalyzed modification of Gomberg-Bachmann-Hey reaction to synthesize symmetrical/unsymmetrical biaryls via diazotization of anilines with p-TSA and NaNO2 system at 50 °C, in aromatic liquids as solvents and second partners was successfully developed. Aniline and 3-nitronaniline gave biphenyl and 3-nitrobiphenyl, respectively, with moderate yields. All para-substituted anilines gave comparatively higher yields while in the other cases including ortho-substituted anilines yields were lower. Except anilines with o-NHCOCH3 and o-CONH2 which gave symmetrical biaryls, all others gave selectively unsymmetrical biaryls.
- Chaturbhuj, Ganesh U.,Akamanchi, Krishnacharya G.
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body text
p. 4950 - 4953
(2011/10/08)
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- Pd-catalyzed sequential C-C and C-N bond formations for the synthesis of N-heterocycles: Exploiting protecting group-directed C-H activation under modified reaction conditions
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Easy & efficient: A Pd-catalyzed domino olefination/conjugate addition reaction of N-Ts-2-arylanilines with activated olefins has been achieved at ambient temperature under the newly defined reaction conditions. This process highlighted the directing effect of the N-protecting group in C-H activation, displayed broad substrate scope with wide functional group compatibility; thus rendering a straightforward entry to a wide variety of N-heterocycles such as dihydrophenanthridines.
- Kim, Byung Seok,Lee, Sun Young,Youn, So Won
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supporting information; experimental part
p. 1952 - 1957
(2011/11/04)
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- Efficient and highly selective iron-catalyzed reduction of nitroarenes
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Pyrolysis of iron-phenanthroline complexes supported on carbon leads to highly selective catalysts for the reduction of structurally diverse nitroarenes to anilines in 90-99% yields. Excellent chemoselectivity for the nitro group reduction is demonstrated.
- Jagadeesh, Rajenahally V.,Wienhoefer, Gerrit,Westerhaus, Felix A.,Surkus, Annette-Enrica,Pohl, Marga-Martina,Junge, Henrik,Junge, Kathrin,Beller, Matthias
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supporting information; experimental part
p. 10972 - 10974
(2011/10/31)
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- A concise synthetic approach towards hydroxytetraphenylenes
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This communication is concerned with our efforts in improving the syntheses of five hydroxytetraphenylens, which we obtained before. A short consecutive direct ortho-metalation and oxidative coupling sequence from N-pivaloyl-protected substituted aniline provided the corresponding 2,2-diiodobiphenyls. Subsequently, copper(II)-mediated oxidative coupling of 2,2-diiodobiphenyls successfully led to the formation of the corresponding hydroxytetraphenylenes. This is the first time that hydroxytetraphenylenes 2, 4 and 5 were all realized via oxidative cross-coupling reactions from the corresponding 2,2-diiodobiphenyls. Georg Thieme Verlag Stuttgart · New York.
- Cui, Jian-Fang,Huang, Hui,Wong, Henry N. C.
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p. 1018 - 1022
(2011/06/17)
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- TRANSITION METAL COMPLEX COMPOUND, OLEFIN POLYMERIZATION CATALYST CONTAINING THE COMPOUND, AND METHOD FOR PRODUCING OLEFIN POLYMER PERFORMED IN THE PRESENCE OF THE CATALYST
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The invention provides transition metal complex compounds, high-activity olefin oligomerization catalysts containing the compounds, and olefin oligomerization processes using the catalysts. A transition metal complex compound [A] according to the invention is represented by Formula (I) or Formula (I') below. An olefin oligomerization catalyst includes the transition metal complex compound [A]. In an olefin oligomerization process of the invention, an olefin is oligomerized in the presence of the catalyst.
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(2010/04/30)
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- Chiral biphenylamide derivative: An efficient organocatalyst for the enantioselective synthesis of α-hydroxy phosphonates
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The aldol reactions of α-keto phosphonates and aldehydes were facilitated by an axially chiral biphenylprolinamide under mild conditions, affording the synthetically and pharmaceutically useful products in high yields and excellent enantioselectivities.
- Jiang, Jun,Chen, Xiaohong,Wang, Jun,Hui, Yonghai,Liu, Xiaohua,Lin, Lili,Feng, Xiaoming
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supporting information; experimental part
p. 4355 - 4357
(2009/12/25)
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- Liquid crystalline behavior of tetraaryl derivatives of benzo[c]cinnoline, tetraazapyrene, phenanthrene, and pyrene: The effect of heteroatom and substitution pattern on phase stability
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A series of closely related tetrasubstituted derivatives of benzo[c]cinnoline (1), tetraazapyrene (2), phenanthrene (3), and pyrene (4) were investigated for their mesogenic properties using thermal, optical, spectroscopic, and powder XRD analyses. Only three 3,4-dioctyloxyphenyl derivatives exhibited mesogenic properties. Substitution of N for CH (3 → 1 and 4 → 2 pairs) and also increase of the core element size (1 → 2 and 3 → 4 pairs) significantly increases the mesophase stability. The findings and observed trends were rationalized by analysis of conformational properties which included calculation of the planarization energy, and modeling of aliphatic chain density and fill fractions. MO calculations showed that the tetraaza derivative 2c is significantly electron deficient and suitable for electron conductive materials. The Royal Society of Chemistry.
- Sienkowska, Monika J.,Farrar, John M.,Zhang, Fan,Kusuma, Sharat,Heiney, Paul A.,Kaszynski, Piotr
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p. 1399 - 1411
(2008/02/07)
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- Arylation of allyl alcohols in organic and aqueous media catalyzed by oxime-derived palladacycles: Synthesis of β-arylated carbonyl compounds
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A 4-hydroxyacetophenone oxime-derived palladacycle catalyzes the Mizoroki-Heck reaction of allyl alcohols with aryl iodides, bromides, and chlorides in aqueous and organic solvents. The reaction takes place in the presence of dicyclohexylmethylamine or cesium carbonate as bases, the addition of tetrabutylammonium bromide (TBAB) as additive for aryl bromides and chlorides being necessary. Under these reaction conditions, β-arylated aldehydes and ketones are mainly obtained using a rather low loading of palladium (0.1-1 mol%). Similar catalytic activity is shown by a Kaiser oxime resin-derived palladacycle, which allows one to perform recycling and reusing experiments with low Pd leaching. The high regio- and chemoselectivity observed supported that these palladacycles, working as a source of Pd(0) species, operates mainly through a neutral mechanism. This methodology has been applied to the synthesis of important β-arylated carbonyl compounds, such as 4-phenylbutan-2-one, 4-(4-hydroxyphenyl)butan-2-one, dihydrochalcones, the anti-inflamatory nabumetone, and the fragance β-lilial. γ-Arylation is observed in the reactions of allyl alcohol and but-3-en-2-ol with 2-iodoaniline giving mainly the corresponding quinolines. The same tendency is observed in the case of 1,1-dimethylallyl alcohol affording either γ-arylated alcohols or (E)-1-arylisoprenes.
- Alacid, Emilio,Najera, Carmen
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p. 2572 - 2584
(2008/09/19)
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- Seven-membered heterocyclic carbenes and their metal complexes
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Disclosed are carbenes of the general formula: and including salts thereof, and metal complexes thereof. The carbenes are useful in any reaction where carbenes and carbene-metal complexes are used. The carbenes disclosed herein are particularly useful in asymmetric catalysis.
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Page/Page column 4; 7
(2010/11/24)
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- Radical reduction of aromatic azides to amines with tributylgermanium hydride
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Aromatic azides are inert toward tributylgermanium hydride under thermal conditions in the absence and in the presence of a radical initiator but in the presence of catalytic amounts of benzenethiol undergo fast reaction, yielding reduced anilines and 2-germylated derivatives in high overall yields.
- Benati, Luisa,Bencivenni, Giorgio,Leardini, Rino,Minozzi, Matteo,Nanni, Daniele,Scialpi, Rosanna,Spagnolo, Piero,Zanardi, Giuseppe
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p. 434 - 437
(2007/10/03)
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- Dual chirality control of palladium(II) complexes bearing tropos biphenyl diamine ligands
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Axial and center chirality of Pd complexes with tropos biphenyl secondary diamine ligands is shown to be controlled by chiral amide (R)-DABNTf, which can efficiently discriminate between two enantiomeric Pd complexes. The Royal Society of Chemistry 2005.
- Aikawa, Kohsuke,Mikami, Koichi
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p. 5799 - 5801
(2008/02/02)
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- Synthesis of 2-nitro- and 2,2′-dinitrobiphenyls by means of the suzuki cross-coupling reaction
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Mechanistic investigations and protocols for the synthesis of 2-nitrobiphenyls and 2,2′-dinitrobiphenyls are disclosed. It is revealed that obstacles appear during the transmetalation step when the phenylboronic acid is substituted with a nitro group in the 2-position, whereas when substituted in the 3- or 4-positions, the reaction follows similar patterns as found in the electrophilic substitution of nitrobenzenes, an observation that may be attributed to the elimination step of the catalytic cycle.
- Gonzalez, Raquel Rodriguez,Liguori, Lucia,Carrillo, Alberto Martinez,Bjorsvik, Hans-Rene
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p. 9591 - 9594
(2007/10/03)
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- New mono- and di-nuclear complexes of PdII, PtII and NiII of PNNP ligands with a 2,2′-biaryl bridging unit
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The Schiff bases 2,2′-bis{N-[(2-diphenylphosphino)phenyl]formimidoyl}biphenyl (L1) and 2,2′-bis{[(2-diphenylphosphino)benzylidene]amino}biphenyl (L2) were synthesized from the appropriate amine and aldehyde. Their co-ordination behaviour towards PdII, PtII and NiII has been studied. Dinuclear complexes were formed when treating L1 with 2 equivalents of [PdCl(Me)(cod)] (cod = cycloocta-1,5-diene) and Pd(O2CMe)2. In the case of the reaction of L1 with Pd(O2CMe)2 an unexpected double cyclopalladated complex was formed. However, treatment of L1 with 2 equivalents of [PtCl2(MeCN)2] resulted in hydrolysis of the ligand and a mononuclear complex of (2-diphenylphosphino)benzenamine was obtained. The structure of [Pd2L1Cl2Me2] 1 has been established by an X-ray diffraction study. The dihedral angle between the biphenyl rings is 49.2(8)° and the intramolecular Pd ... Pd distance is 7.165(3) A. The biphenyl bridging moiety shows a remarkable bending of 169.2(8)°. Treatment of 1 with carbon monoxide resulted in a double CO insertion, yielding the bis(acetyl)palladium compound [Pd2L1Cl2-{C(O)Me}2] 2. The structure of [Pd2L1(O2CMe)2]·4CH 2Cl2 3 was also determined by X-ray diffraction. The dihedral angle between the biphenyl rings is 75.9(14)° while the intramolecular Pd ... Pd distance is 8.655(2) A. The reaction of L2 with 2 equivalents of anhydrous [PdCl2(MeCN)2] or NiCl2 afforded mononuclear complexes. The crystal and molecular structure of [PdL2]Cl2·3.5CH2Cl2 was determined. The compound has an approximately square-planar P2N2 geometry.
- Ligtenbarg, Alette G. J.,Van Den Beuken, Esther K.,Meetsma, Auke,Veldman, Nora,Smeets, Wilberth J. J.,Spek, Anthony L.,Feringa, Ben L.
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p. 263 - 270
(2007/10/03)
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- Organometallic chemistry sans organometallic reagents: Modulated electron-transfer reactions of sub valent early transition metal salts
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The potential of low-valent, early transition-metal reagents as selective reductants in organic chemistry has been foreshadowed by intensive research on the ill-defined and heterogeneous subvalent titanium intermediates generated in the McMurry reaction and its numerous variants. As part of a long-term research effort to develop soluble, well-defined transition-metal reductants of modulated and selective activity toward organic substrates, the THF-soluble reductant, titanium dichloride, has been thoroughly examined, as well as the analogous ZrCl2 and HfCl2 reagents, all of which are readily obtainable by the alkylative reduction of the Group 4 tetrachloride by butyllithium in THF. Noteworthy is that such interactions of MCl4, with butyllithium in hydrocarbon media lead, in contrast, to M(III) or M(IV) halide hydrides. Analogous alkylative reductions in THF applied to VCl4, CrCl3, and MoCl5 have yielded reducing agents similar to those obtained from MCl4 but gradated in their reactivity. Such reductants have proved capable of coupling carbonyl derivatives, benzylic halides, acetylenes and certain olefins in a manner consistent with an oxidative addition involving a two-electron transfer (TET). Such a reaction pathway is consistent with the observed stereochemistry for pinacol formation from ketones and for the reductive dimerization of alkynes. In contrast to the reaction of CrCl3 with two equivalents of butyllithium, which leads to a CrCl intermediate, the interaction of CrCl3 in THF with four equivalents of butyllithium at -78°C yields a reagent of the empirical formulation, LiCrH4 · 2 LiCl · 2 THF, as supported by elemental and gasometric analysis of its protolysis. This hydridic reductant cleaves a wide gamut of o carbon-heteroatom bonds (C-X, C-O, C-S and C-N), towards which the CrCl reductant is unreactive. The type of cleavage and/or coupled products resulting from the action of "LiCrH4" on these substrates is best understood as arising from single-electron transfer (SET). In light of the aforementioned findings, the gradated reducing action noted among TiCl2, ZrCl2, HfCl2 and CrCl, as well as the contrasting reducing behavior between CrCl and LiCrH4, there is no doubt that future research with early transition metals will continue to yield novel reductants of modulated and site-selective reactivity. VCH Verlagsgesellschaft mbH,.
- Eisch, John J.,Shi, Xian,Alila, Joseph R.,Thiele, Sven
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p. 1175 - 1187
(2007/10/03)
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- Alternative synthesis of dibenzo-and dipyrido-[1,3]diazepines from thioamides and o,o'-diaminobiaryls
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Thioamides were treated with iodomethane, and then o,o'-diaminobiphenyl or bipyridyl to afford 6-substituted-5H-dibenzo- or dipyrido [1,3]diazepines in good yields.
- Matsuda, Koyo,Yanagisawa, Isao,Isomura, Yasuo,Mase, Toshiyasu,Shibanuma, Tadao
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p. 2393 - 2402
(2007/10/03)
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- Photolysis of 2-Amino-2'-azidobiphenyls: Formal Formation of Internally Trapped Didehydroazepines
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Photolysis of 2-amino-2'-azidobiphenyls in diethylamine gave 4,10-dihydroazepinoindoles (7), the structure of which corresponded to the didehydroazepines formally trapped with an internal amino group.However, the yields of 7 were considered low, which was due to the significant intramolecular interaction of the photolytically generated nitrene with an amino group, to afford benzocinnoline as a final product.
- Murata, Shigeru,Tsuji, Hiroshi,Tomioka, Hideo
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p. 895 - 897
(2007/10/02)
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- Photochemistry of Tetrabenzotetraazacyclododecine in 2-Propanol
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The photochemical properties of the tetraazacyclododecine 1 were investigated.The trans,trans isomer 1tt can be photoisomerized yielding the stable cis,cis isomer 1cc.The isomerization requires two photons and proceeds via the unstable trans,cis isomer 1tc.In nitrogen-purged 2-propanol as solvent 1 yields five stable photoproducts as a result of a number of consecutive photoreduction reactions.Our attempts to convert 1 by light into the tetraazetidine 4 were not successful. Key Words: cis-Azo compounds / Photoreduction / Tetrabenzotetraazacyclododecine
- Tauer, Erich,Grellmann, Karl-Heinz,Heinrich, Angelika
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p. 2053 - 2055
(2007/10/02)
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- Observations on the Reduction of Aryl Nitro Groups with Palladium-Sodium Borohydride
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The reduction of aryl nitro groups by the palladium-sodium borohydride system can be controlled in some instances to give products differing from those of catalytic hydrogenation.With six equivalents of borohydride added to the catalyst 2,2'-dinitrobiphenyl formed only 2,2'-diaminobiphenyl.With added sodium hydroxide and varying amounts of borohydride and catalyst, the reduction can be controlled to give benzocinnoline, benzocinnoline 5-oxide or benzocinnoline 5,6-dioxide.In a closed system, the reagents reduce both the nitro and olefin functional groups in 6-nitro-5,8-dimethoxy-1,4-dihydro-1,4-ethanonaphtalene.In an open flask flushed with argon, the reduction is confirmed to the nitro group.Reduction of 2-chloro and 4-chloronitrobenzene with palladium-borohydride gives substantial yields of the appropriate chloroanilines.In contrast, hydrogen and palladium give aniline as the major product from each of these.These results suggest that the addition of sodium borohydride to palladium on carbon produces a reductive entity differing from that of catalytic hydrogenation.
- Smith, William B.
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p. 745 - 748
(2007/10/02)
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- A zerovalent nickel-2,2'-bipyridine complex: an efficient catalyst for electrochemical homocoupling of ortho-substituted halides and their heterocoupling with meta- and para-substituted halides
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Electroreduction of ortho-substituted halides Ar-X in a nickel-2,2'-bipyridyl system and N-methylpyrrolidone as solvent gave the homocoupling product ArAr.The nickel-2,2'-bipyridyl system is also a catalyst for the electrochemical heterocoupling of ArX with meta- or para-substituted halides Ar'X'.
- Meyer, Gilbert,Rollin, Yolande,Perichon, Jacques
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p. 263 - 268
(2007/10/02)
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- Direct Photoamination of Arenes with Ammonia and Primary Amines in the Presence of Electron Acceptors
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Direct photoamination of phenanthrene, 9-methoxyphenanthrene, anthracene, naphthalene, and several substituted naphthalenes with ammonia or primary amines in the presence of m-dicyanobenzene occurs to give aminated dihydroarenes in fairly good yields. m-Dimethoxybenzene and biphenyl are photoaminated in lower yields.A suggested mechanism for the photoamination involves the nucleophilic attack of ammonia and amines on aromatic cation radicals generated by photochemical electron transfer to m-dicyanobenzene.The present photoamination is applied to direct introduction of various functionalized primary amines containing the vinyl, cyano, hydroxy, acetylamino, and ethoxycarbonyl groups.
- Yasuda, Masahide,Yamashita, Toshiaki,Shima, Kensuke,Pac, Chyongjin
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p. 753 - 759
(2007/10/02)
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- Schmidt reaction of some constrained aromatic acids, and related topics
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Schmidt reaction of phthalic acid in 90-98percent sulfuric acid gives anthranilic acid and anthranilazide (major products) by a process considered to involve 3,1-benzoxazin-2,4(1H)-dione as intermediate.Benzimidazol-2-one is produced in this reaction by a secondary process from anthranilazide; it is also produced by photolysis of anthranilazide.Under Schmidt reaction conditions, 1,2,3-benzotriazin-4(3H)-one gives o-azidobenzamide.Under similar conditions, the lactol of 4-formyl-5-phenanthroic acid gives 1-azapyren-2(1H)-one and phenanthrene-4,5-dicarboximide, while phenanthrene-4,5-dicarboxylic acid gives 1-azapyren-2(1H)-one.Diphenic acid yields phenanthridone and 2,2'-diaminobiphenyl in proportions dependent on the sulfuric acid concentration.
- Ruediger, Edward H.,Gandhi, Sham S.,Gibson, Martin S.,Farcasiu, Dan,Uncuta, Cornelia
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p. 577 - 579
(2007/10/02)
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- The Photochemical Reaction of Benzocinnoline. IV. Comments on the Mechanism of 2,2'-Diaminobiphenyl Formation
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In order to determine the mechanism of 2,2'-diaminobiphenyl formation from benzocinnoline, effect of aldehyde on the reaction was examined.It is proposed that ethanal, which was generated from ethanol in the initial photoreduction, formed an adduct with 5,6-dihydrobenzocinnoline, and that the resulting adduct participated in the subsequent photo-induced 2,2'-diaminobiphenyl formation.
- Inoue, Hiroyasu,Hiroshima, Yukimi,Sakai, Toshihiko,Sakurai, Tadamitsu,Fukuda, Norio
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p. 2829 - 2830
(2007/10/02)
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