- An unexpected base-induced rearrangement of tritylamine
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An unexpected rearrangement was observed during the treatment of tritylamine with n-butyllithium, leading to the formation of an imine.
- Theodorou, Vassiliki,Skobridis, Konstantinos
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Read Online
- Novel functional groups with fine-controlled metal assembling function
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Half-substituted dendritic phenylazomethine dendrimers with various substituents (Half-DPA-X Gn, where n is the generation number) were synthesized in order to elucidate the electron gradients in the dendrons by complexation with metal ions. Along with th
- Yamamoto, Kimihisa,Higuchi, Masayoshi,Kimoto, Atsushi,Imaoka, Takane,Masachika, Kiriko
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Read Online
- Selective Synthesis of Novel Cyclic Phenylazomethine Trimers
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Novel cyclic phenylazomethine trimers (CPAs) were synthesized in a one-step dehydration of the 4-aminobenzophenone derivatives in the presence of TiCl4 or p-toluenesulfonic acid (PTS). The CPAs were isolated in over 90% yield under nondilute co
- Higuchi, Masayoshi,Kimoto, Atsushi,Shiki, Satoshi,Yamamoto, Kimihisa
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Read Online
- Photoredox-Catalyzed Synthesis of α-Amino Acid Amides by Imine Carbamoylation
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An operationally simple protocol for the photocatalytic carbamoylation of imines is reported. Easily available, bench-stable 4-amido Hantzsch ester derivatives serve as precursors to carbamoyl radicals that undergo rapid addition to N-aryl imines. The reaction proceeds under blue light irradiation in the presence of the photocatalyst 3DPAFIPN and Br?nsted/Lewis acid additives. Mechanistic studies indicated a photoredox mechanism that involves carbamoyl radicals.
- Cardinale, Luana,Schmotz, Mattis-Ole W. S.,Konev, Mikhail O.,Jacobi von Wangelin, Axel
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supporting information
p. 506 - 510
(2022/01/20)
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- Copper-Catalysed Electrophilic Amination of Aryl(alkenyl) Boronic Acids with Nitrogen-Containing Hypervalent Iodine (III) Reagent
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A copper-catalysed electrophilic N-imination of aryl(alkenyl) boronic acids with a stable hypervalent iodine(III) reagent containing a transferable (diarylmethylene)amino group is developed. The electrophilic C?N cross-coupling reaction proceeds smoothly at room temperature under oxidant-free and base-free conditions, which is further characterized by the broad functional group compatibility, thereof, extending the N-electrophile scope of electrophilic C?N cross-coupling outside the limitation of N?O and N?Cl reagents. (Figure presented.).
- Hu, Yuanyuan,Zheng, Songlin,Fan, Wu,Yuan, Weiming
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supporting information
p. 4701 - 4707
(2021/08/23)
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- Iodine-mediated 1,2-aryl migration of primary benzhydryl amines
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An iodine-mediated 1,2-aryl migration reaction of primary benzhydryl amines under transition metal-free conditions has been achieved. The crude imines generated by this rearrangement reaction can be directly transformed into various aromatic secondary ami
- Chang, Junbiao,Du, Yangxu,Hao, Wei,Hou, Jiao,Lu, Qing,Yu, Wenquan
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supporting information
p. 16223 - 16226
(2021/09/22)
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- Visible-Light-Induced Cycloaddition of α-Ketoacylsilanes with Imines: Facile Access to β-Lactams
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We report the synthesis of β-lactams from α-ketoacylsilanes and imines, which proceeds via a formal [2+2] photochemical cycloaddition with in situ generation of siloxyketene. This mild and operationally simple reaction proceeds in an atom-economic fashion with broad substrate scope, including aldimines, ketimines, hydrazones, and fused nitrogen heterocycles, affording a variety of important β-lactams with satisfactory diastereoselectivities in most cases. This reaction also features good functional-group tolerance, facile scalability and product diversification. Experimental and computational studies suggest that α-ketoacylsilanes can serve as photochemical precursors by engaging in a 1,3 silicon shift to the distal carbonyl group.
- Ye, Jian-Heng,Bellotti, Peter,Paulisch, Tiffany O.,Daniliuc, Constantin G.,Glorius, Frank
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supporting information
p. 13671 - 13676
(2021/05/11)
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- An expedient one-pot synthesis of benzophenone Schiff bases from benzene
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A simple and efficient one-pot synthesis of benzophenone Schiff bases from benzene, CCl4 and aromatic amines was developed based on the the reaction of benzene with CCl4·AlCl3 complex. This method affords Ph2CCl2 as well as the products of its subsequent reaction with aromatic amines, benzophenone Schiff bases, selectively and in good yields.
- Akhrem, Irena S.,Afanas'eva, Lyudmila V.,Avetisyan, Dzhul'etta V.,Artyushin, Oleg I.,Kagramanov, Nikolai D.
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p. 238 - 240
(2020/05/25)
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- Iron-catalysed 1,2-aryl migration of tertiary azides
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1,2-Aryl migration of α,α-diaryl tertiary azides was achieved by using the catalytic system of FeCl2/N-heterocyclic carbene (NHC) SIPr·HCl. The reaction generated aniline products in good yields after one-pot reduction of the migration-resultant imines.
- Wei, Kaijie,Yang, Tonghao,Chen, Qing,Liang, Siyu,Yu, Wei
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supporting information
p. 11685 - 11688
(2020/10/19)
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- Cu/Ni-doped sulfated zirconium oxide immobilized on CdFe2O4 NPs: a cheap, sustainable and magnetically recyclable inorgano-catalyst for the efficient preparation of α-aminonitriles in aqueous media
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Abstract: A new multifunctional bimetallic nanocatalyst was prepared by immobilization of Cu/Ni-doped sulfated zirconium oxide on magnetic cadmium ferrite (CdFe2O4@SiO2@ZrO2/SO42?/Cu/Ni) and used as an efficient recyclable catalyst for one-pot as well as stepwise preparation of α-aminonitriles under mild conditions. The magnetic nanocatalyst was characterized by FTIR, TGA, VSM, XRD, EDX, FE-SEM, and TEM analyses. Also, the surface acidity of the catalyst was measured by pyridine adsorption assay. The catalyst possesses various active sites which could catalyst a variety of aromatic and aliphatic aldehydes to the corresponding α-amionitriles under moderate to high yields in the presence of aniline. Furthermore, transformation of ketones to the desired α-amionitriles and some bis-aminonitriles was also performed by this method. The catalyst could be readily recovered from the reaction mixture and reused for several times without significant loss of activity. Graphic abstract: A general and efficient method has been developed for transformation of a variety of aliphatic, aromatic aldehydes and ketones to the corresponding α-aminonitriles using a multifunctional recyclable CdFe2O4@SiO2@ZrO2/SO42?/Cu/Ni nanocatalyst.[Figure not available: see fulltext.]
- Nasseri, Mohammad Ali,Ramezani-Moghadam, Simin,Kazemnejadi, Milad,Allahresani, Ali
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p. 4233 - 4256
(2020/07/08)
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- ROMP-Boranes as Moisture-Tolerant and Recyclable Lewis Acid Organocatalysts
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Although widely used in catalysis, the multistep syntheses and high loadings typically employed are limiting broader implementation of highly active tailor-made arylborane Lewis acids and Lewis pairs. Attempts at developing recyclable systems have thus far met with limited success, as general and versatile platforms are yet to be developed. We demonstrate a novel approach that is based on the excellent control and functional group tolerance of ring-opening metathesis polymerization (ROMP). The ROMP of highly Lewis acidic borane-functionalized phenylnorbornenes afforded both a soluble linear copolymer and a cross-linked organogel. The polymers proved highly efficient as recyclable catalysts in the reductive N-alkylation of arylamines under mild conditions and at exceptionally low catalyst loadings. The modular design presented herein can be readily adapted to other finely tuned triarylboranes, enabling wide applications of ROMP-borane polymers as well-defined supported organocatalysts.
- Vidal, Fernando,McQuade, James,Lalancette, Roger,J?kle, Frieder
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supporting information
p. 14427 - 14431
(2020/10/13)
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- General synthesis of N-Alkylation of amines with secondary alcohols via hydrogen autotransfer
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Direct catalytic N-alkylation of amines with secondary alcohols via hydrogen autotransfer (HA) strategy is very challenging and has been scarcely reported, even under precious metal catalysis. Herein, an efficient N-alkylation of amines, including benzyla
- Subaramanian, Murugan,Midya, Siba P.,Ramar, Palmurukan M.,Balaraman, Ekambaram
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supporting information
p. 8899 - 8903
(2019/11/14)
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- Oxidative Rearrangement of Primary Amines Using PhI(OAc)2 and Cs2CO3
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An oxidative rearrangement of primary amines mediated by a hypervalent iodine(III) reagent is herein reported. The combination of PhI(OAc)2 and Cs2CO3 proves highly efficient at inducing the direct 1,2-C to N migration of primary amines, which can be applied to the preparation of both acyclic and cyclic amines. A mechanistic study shows that the rearrangement proceeds via a concerted mechanism.
- Yamakoshi, Wataru,Arisawa, Mitsuhiro,Murai, Kenichi
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supporting information
(2019/05/08)
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- Photoredox Radical/Polar Crossover Enables Construction of Saturated Nitrogen Heterocycles
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Photoredox-mediated radical/polar crossover (RPC) processes offer new avenues for the synthesis of cyclic molecules. This process has been realized for the construction of medium-sized saturated nitrogen heterocycles. Photocatalytically generated alkyl ra
- Pantaine, Lo?c R.E.,Milligan, John A.,Matsui, Jennifer K.,Kelly, Christopher B.,Molander, Gary A.
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supporting information
p. 2317 - 2321
(2019/03/26)
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- Disulfonimides versus phosphoric acids in br?nsted acid catalysis: The effect of weak hydrogen bonds and multiple acceptors on complex structures and reactivity
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In Br?nsted acid catalysis, hydrogen bonds play a crucial role for reactivity and selectivity. However, the contribution of weak hydrogen bonds or multiple acceptors has been unclear so far since it is extremely difficult to collect experimental evidence
- Rothermel, Kerstin,?abka, Matej,Hioe, Johnny,Gschwind, Ruth M.
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p. 13221 - 13231
(2019/10/16)
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- Benzhydrylamine: An effective aminating agent for the synthesis of primary amines
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Aldehydes, ketones, alkyl toluene-p-sulfonates and halides are converted into the corresponding primary amines with benzhydrylamine as a valuable ammonia synthon in moderate to excellent yields.
- Sun, Quan-Wei,Xing, Jun-De,Qin, Yu-Hong,Yin, Xu-Wen,Zhou, Yi
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p. 181 - 183
(2018/05/26)
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- Visible-Light-Mediated Umpolung Reactivity of Imines: Ketimine Reductions with Cy2NMe and Water
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A novel carbanionic reactivity of imines mediated by photoredox catalysis is demonstrated. The umpolung imine reactivity is exemplified by proton abstraction from water as a key step in the reduction of benzophenone ketimines to amines (up to 98% yield). Deuterium is introduced into amines efficiently using D2O as an inexpensive deuterium source (≥95% D ratio). The mechanism of this unusual transformation is probed.
- Wang, Rui,Ma, Mengyue,Gong, Xu,Panetti, Grace B.,Fan, Xinyuan,Walsh, Patrick J.
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supporting information
p. 2433 - 2436
(2018/04/27)
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- Photocatalytic and Chemoselective Transfer Hydrogenation of Diarylimines in Batch and Continuous Flow
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A visible-light photocalytic method for the chemoselective transfer hydrogenation of imines in batch and continuous flow is described. The reaction utilizes Et3N as both hydrogen source and single-electron donor, enabling the selective reduction of imines derived from diarylketimines containing other reducible functional groups including nitriles, halides, esters, and ketones. The dual role of Et3N was confirmed by fluorescence quenching measurements, transient absorption spectroscopy, and deuterium-labeling studies. Continuous-flow processing facilitates straightforward scale-up of the reaction.
- Van As, Dean J.,Connell, Timothy U.,Brzozowski, Martin,Scully, Andrew D.,Polyzos, Anastasios
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supporting information
p. 905 - 908
(2018/02/22)
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- Transition-Metal-Free Addition of Acetylenes to Ketimines: the First Base-Catalyzed Ethynylation of the C=N Bond
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A one-pot transition metal-free synthesis of propargylamines in good to excellent yield from ketone-derived imines and aryl- and hetarylacetylenes in the presence of KOBut/DMSO superbase system (40 °C, 10 min) has been developed. The reaction i
- Bidusenko, Ivan A.,Schmidt, Elena Yu.,Ushakov, Igor A.,Trofimov, Boris A.
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supporting information
p. 4845 - 4849
(2018/09/14)
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- Visible-Light Photocatalytic Synthesis of Amines from Imines via Transfer Hydrogenation Using Quantum Dots as Catalysts
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CdSe/CdS core/shell quantum dots (QDs) can be used as stable and highly active photoredox catalysts for efficient transfer hydrogenation of imines to amines with thiophenol as a hydrogen atom donor. This reaction proceeds via a proton-coupled electron transfer (PCET) from the QDs conduction band to the protonated imine followed by hydrogen atom transfer from the thiophenol to the α-aminoalkyl radical. This precious metal free transformation is easy to scale up and can be carried out by a one-pot protocol directly from aldehyde, amine, and thiophenol. Additional advantageous features of this protocol include a wide substrate scope, high yield of the amine products, extremely low catalyst loading (0.001 mol %), high turnover number (105), and the mild reaction conditions of using visible light or sun light at room temperature in neutral media.
- Xi, Zi-Wei,Yang, Lei,Wang, Dan-Yan,Pu, Chao-Dan,Shen, Yong-Miao,Wu, Chuan-De,Peng, Xiao-Gang
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p. 11886 - 11895
(2018/09/25)
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- Osmium Hydride Acetylacetonate Complexes and Their Application in Acceptorless Dehydrogenative Coupling of Alcohols and Amines and for the Dehydrogenation of Cyclic Amines
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The preparation of new osmium hydride complexes, starting from OsH6(PiPr3)2 (1) and OsH2Cl2(PiPr3)2 (2), and their catalytic activity in acceptorless dehydrogenative coupling of alcohols and amines and in dehydrogenation of cyclic amines are reported. Complex 1 reacts with acetylacetone (Hacac) to give the classical trihydride OsH3(acac)(PiPr3)2 (3). The protonation of 3 with triflic acid (HOTf) produces the release of H2 and the formation of the unsaturated osmium(IV) dihydride [OsH2(acac)(PiPr3)2]OTf (4), which is also prepared by starting from 2 via the intermediate OsH2Cl(acac)(PiPr3)2 (5). Treatment of an acetylacetone solution of 5 with KOH affords Os(acac)2(PiPr3)2 (6). In the presence of 5 mol % of KOH, complexes 3-6 promote the coupling of benzyl alcohol and aniline to give N-benzylideneaniline and H2. Under the same conditions, complex 3 catalyzes a wide range of analogous couplings to afford a variety of imines, including aliphatic imines, with yields between 90 and 40% after 1-48 h. Complex 3 also catalyzes the dehydrogenation of cyclic amines. According to the amount of H2 released by each 1 g of employed substrate, the amines have been classified into three classes: poor (1,2,3,4-tetrahydroquinaldine, 2-methylindoline, and 2,6-dimethylpiperidine), moderate (1,2,3,4-tetrahydroquinoline and 6-methyl-1,2,3,4-tetrahydroquinoline), and good hydrogen donors (1,2,3,4-tetrahydroisoquinoline).
- Esteruelas, Miguel A.,Lezáun, Virginia,Martínez, Antonio,Oliván, Montserrat,Onate, Enrique
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p. 2996 - 3004
(2017/08/21)
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- Decrypting Transition States by Light: Photoisomerization as a Mechanistic Tool in Br?nsted Acid Catalysis
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Despite the wide applicability of enantioselective Br?nsted acid catalysis, experimental insight into transition states is very rare, and most of the mechanistic knowledge is gained by theoretical calculations. Here, we present an alternative approach (de
- Renzi, Polyssena,Hioe, Johnny,Gschwind, Ruth M.
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supporting information
p. 6752 - 6760
(2017/05/29)
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- CATALYTIC SYSTEM FOR CROSS-COUPLING REACTIONS
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The present invention concerns a process for creating a Carbon-Carbon bond (C—C) or a Carbon-Heteroatom bond (C—HE) by reacting a compound carrying a leaving group with a nucleophilic compound carrying a carbon atom or a heteroatom (HE) that can substitute for the leaving group, creating a C—C or C—HE bond, wherein the reaction takes place in the presence of an effective quantity of a. a catalytic system comprising a ligand and at least a metal-based catalyst, such a metal catalyst being chosen among iron or copper compounds proviso that only a single metal is present.
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Paragraph 0308-0311
(2016/06/06)
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- An umpolung approach toward N-aryl nitrone construction: A phosphine-mediated addition of 1,2-dicarbonyls to nitroso electrophiles
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An umpolung approach toward nitrone construction utilizing a phosphine-mediated addition of 1,2-dicarbonyls to nitroso compounds is reported. The reaction exhibits a high degree of chemoselectivity and provides direct access to isoxazolidines, imines, and
- Chavannavar, Aditi P.,Oliver, Allen G.,Ashfeld, Brandon L.
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supporting information
p. 10853 - 10856
(2014/10/16)
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- Cyclopalladated benzophenone imines: Synthesis, antitumor activity, cell accumulation, dna interaction, and cathepsin b inhibition
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The synthesis of the endo five-membered cyclo-ortho-palladated benzophenone imines [Pd{C6H4(Ph)C=NR}]2(μ-X)2 [1 (X = OAc), 2 (X = Cl), a (R = phenyl), b (R = 1-naphthyl), c (R = benzyl), d (R = α-methylbenzyl)], and trans-N,P-[Pd{C6H4(Ph)C=NR}X(PPh3)] [3 (X = OAc), 4 (X = Cl), a (R = phenyl), b (R = 1-naphthyl), c (R = benzyl), d (R = α-methylbenzyl)] and the X-ray molecular structure of 1a, 1c, 1d, 4a, 4b, and 4c are reported. The antitumor activity, DNA interaction, and cathepsin B inhibition of palladium compounds a-d were studied and compared with those previously reported for palladium compounds e with R = H and compound 4f analogous to 4e but with a platinum(II) center. The IC50 values against a panel of human cancer cell lines allowed the establishment of a qualitative relationship between their structure and antitumor activity. Compounds 3e, 4e, and 4f were the most active ones in relation to their in vitro anticancer activity. Compounds 3e and 4e were about 4 times more active than cisplatin against the MDA-MB-231 and MCF-7 breast human cancer lines, and compound 4f was about 4 times more active than cisplatin against the cisplatin-resistant HCT-116 colon human cancer cell line. In addition, compound 3e was 3 times less cytotoxic than cisplatin toward the quiescent HUVEC cells. Accumulation of palladium compounds e and b in the MDA-MB-231 cell line was considerably greater than that of cisplatin in the same cell line, but palladium compounds b were noncytotoxic. Some of these complexes altered the DNA tertiary structure in a similar way to cisplatin but at higher concentration, and most cytotoxic ones did not present a high efficiency as cathepsin B inhibitors.
- Albert, Joan,Granell, Jaume,Qadir, Romana,Quirante, Josefina,Calvis, Carme,Messeguer, Ramon,Bada, Josefa,Baldom, Laura,Font-Bardia, Merc,Calvet, Teresa
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supporting information
p. 7284 - 7292
(2015/03/03)
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- Ratiometric fluorescent probes for detection of intracellular singlet oxygen
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We have developed a series of molecular probes for the fluorescent detection of singlet dioxygen (1O2). The probes, based on asymmetrically substituted 1,3-diarylisobenzofurans, undergo the [2 + 4] cycloaddition reaction with 1O2, producing ratiometric fluorescent responses. Two-photon fluorescence microscope experiments demonstrated the biological utility of the probes for the visualization of endogenous 1O2 in macrophage cells.
- Song, Dayoung,Cho, Somin,Han, Yejee,You, Youngmin,Nam, Wonwoo
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supporting information
p. 3582 - 3585
(2013/08/23)
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- Magnesium catalysis of imine hydroboration
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The β-diketiminato magnesium alkyl complex [LMgnBu] (L=CH{CMe(NDipp)}2, Dipp=diisopropylphenyl) is shown to be a highly effective precatalyst for the hydroboration of alkyl and aryl substituted aldimines and ketimines with pinacol borane (HBpin). Catalysis is proposed to occur through a sequence of Mg-N/B-H metathesis and rate-determining Mg-H/N=C insertion steps, a proposal strongly supported by stoichiometric studies and kinetic analysis. The reactions are observed to proceed through the intermediacy of well-defined magnesium amides, two examples of which have been isolated and structurally characterized. Mechanistic investigations suggest that the catalytic rate-determining process occurs at an isolated magnesium center and requires the presence of two molecules of the imine substrate for effective turnover. This latter observation is rationalized as a requirement for the secondary substrate molecule to displace HBpin from the coordination sphere of the catalytic magnesium center.
- Arrowsmith, Merle,Hill, Michael S.,Kociok-Koehn, Gabriele
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supporting information
p. 2776 - 2783
(2013/03/14)
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- NOVEL CATALYSTS
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The present invention provides novel compounds and ligands that are useful in transition metal catalyzed cross-coupling reactions. For example, the compounds and ligands of the present invention are useful in palladium or gold catalyzed cross-coupling reactions.
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Page/Page column 66
(2012/06/01)
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- Facile synthesis of triarylmethanimine promoted by a lewis acidbase pair: Theoretical and experimental studies
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An efficient method for triarylmethanimine synthesis promoted by a Lewis acidbase pair (AlCl3Et3N) was designed using mechanistic analysis with the aid of density functional theory. A series of triarylmethanimines were successfully prepared under mild con
- Liu, Yan,Yang, Qiwu,Hao, Dongling,Zhang, Wenqin
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p. 1390 - 1395,6
(2020/09/02)
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- Montmorillonite as a heterogeneous catalyst in the efficient, mild and one pot synthesis of Schiff bases under solvent-free conditions
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A mild and efficient method has been reported for preparation of Schiff base ligands through condensation reaction of various aromatic aldehydes and ketones with different aromatic amines in the presence of montmorillonite as a heterogeneous catalyst under solvent free conditions. The advantages of this friendly, economically, environmentally and mild method are such as; simplicity of the reaction procedure, reusability of catalyst, simple work-up, high product yields and very short reaction times.
- Naeimi, Hossein,Rabiei, Khadijeh
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experimental part
p. 208 - 212
(2012/07/03)
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- Expedient synthesis of functionalized triarylmethanols through tandem formation of geminal C-C and C-O bonds
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The rearrangement/oxidation of N,N-disubstituted anilines and the formal dehydrogenative cross-coupling of diarylmethanols with aniline derivatives have been developed for the preparation of symmetric and unsymmetric functionalized triarylmethanols. Both reactions proceed smoothly in trifluoroacetic acid in the presence of an inexpensive oxidant (manganese dioxide or potassium persulfate) and a catalytic amount of palladium diacetate to give a range of functionalized triarylmethanols in moderate to good yields and with extremely high regioselectivity. The two unprecedented reactions involve tandem formation of geminal C-C and C-O bonds, and they are synthetically useful, atom-efficient, and operationally simple.
- Tian,Sui, Yi,Gu, Yonghong,Tian, Shi-Kai
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supporting information
p. 3475 - 3479
(2013/02/22)
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- Thermolysis and photolysis of N-benzoylhydrazone derivatives
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Two selected N-benzoylhydrazones were subjected to thermolysis by refluxing at 200 °C. Benzil, benzoic acid, biphenyl, benzanilide together with the corresponding ketones, nitriles, substituted methanes, and imines were isolated. Similar treatment of a third hydrazone at 250 °C afforded, in addition to the previous products, toluene, bibenzyl, stilbene, and 2-phenylindole. Photolysis of the same hydrazones in acetonitrile gave the previously reported products but in different ratios along with azine derivatives and substituted methanes. A free radical mechanism involving homolysis of the N-N and C-N bonds is suggested, substantiated by trapping of the phenyl radical with isoquinoline, to account for the formation of the identified products.
- Gaber, Abd El-Aal M.,Khairou, Khalid S.
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experimental part
p. 1021 - 1027
(2012/07/27)
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- New Catalytic System for Cross-Coupling Reactions
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The present invention concerns a process for creating a Carbon-Carbon bond (C—C) or a Carbon-Heteroatom bond (C-HE) by reacting a compound carrying a leaving group with a nucleophilic compound carrying a carbon atom or a heteroatom (HE) that can substitute for the leaving group, creating a C—C or C-HE bond, wherein the reaction takes place in the presence of an effective quantity of a. a catalytic system comprising a ligand and at least a metal-based catalyst, such a metal catalyst being chosen among iron or copper compounds proviso that only a single metal is present.
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Page/Page column 14
(2012/01/03)
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- Hydride, hydrogen, proton, and electron affinities of imines and their reaction intermediates in acetonitrile and construction of thermodynamic characteristic graphs (TCGs) of imines as a molecule ID card
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(Chemical Equation Presented) A series of 61 imines with various typical structures were synthesized, and the thermodynamic affinities (defined as enthalpy changes or redox potentials in this work) of the imines to abstract hydride anions, hydrogen atoms, and electrons, the thermodynamic affinities of the radical anions of the imines to abstract hydrogen atoms and protons, and the thermodynamic affinities of the hydrogen adducts of the imines to abstract electrons in acetonitrile were determined by using titration calorimetry and electrochemical methods. The pure heterolytic and homolytic dissociation energies of the C=N π-bond in the imines were estimated. The polarity of the C=N double bond in the imines was examined using a linear free-energy relationship. The idea of a thermodynamic characteristic graph (TCG) of imines as an efficient Molecule ID Card was introduced. The TCG can be used to quantitatively diagnose and predict the characteristic chemical properties of imines and their various reaction intermediates as well as the reduction mechanism of the imines. The information disclosed in this work could not only supply a gap of thermodynamics for the chemistry of imines but also strongly promote the fast development of the applications of imines. 2009 American Chemical Society.
- Zhu, Xiao-Qing,Liu, Qiao-Yun,Chen, Qiang,Mei, Lian-Rui
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scheme or table
p. 789 - 808
(2010/04/29)
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- A highly versatile catalyst system for the cross-coupling of aryl chlorides and Amines
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The syntheses of 2-(di-tertbutylphosphino)-N,N-dimethylaniline (L1, 71%) and 2-(di-1-adamantylphosphino)-N,N-dimethylaniline (L2, 74%), and their application in BuchwaldHartwig amination, are reported. In combination with [Pd(allyl)Cl]2 or [Pd(cinnamyl)Cl]2, these structurally simple and air-stable P,N ligands enable the cross-coupling of aryl and heteroaryl chlorides, including those bearing as substituents enolizable ketones, ethers, esters, carboxylic acids, phenols, alcohols, olefins, amides, and halogens, to a diverse range of amine and related substrates that includes primary alkyl- and arylamines, cyclic and acyclic secondary amines, N-H imines, hydrazones, lithium amide, and ammonia. In many cases, the reactions can be performed at low catalyst loadings (0.5-0.02 mol % Pd) with excellent functional group tolerance and chemoselectivity. Examples of cross-coupling reactions involving 1,4-bromochlorobenzene and iodobenzene are also reported. Under similar conditions, inferior catalytic performance was achieved when using Pd(OAc)2, PdCl2, [PdCl2(cod)] (cod = 1,5-cyclooctadiene), [PdCl 2(MeCN)2], or [Pd2(dba)3] (dba = dibenzylideneacetone) in combination with L1 or L2, or by use of [Pd(allyl)Cl]2 or [Pd(cinnamyl)Cl]2 with variants of L1 and L2 bearing less basic or less sterically demanding substituents on phosphorus or lacking an ortto-dimethylamino fragment. Given current limitations associated with established ligand classes with regard to maintaining high activity across the diverse possible range of C-N coupling applications, L1 and L2 represent unusually versatile ligand systems for the cross-coupling of aryl chlorides and amines
- Lundgren, Rylan J.,Sappong-Kumankumah, Antonia,Stradiotto, Mark
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supporting information; experimental part
p. 1983 - 1991
(2010/07/03)
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- One-pot reductive n-alkylation with carbonyl compounds to give tertiary amines via borane reduction of imines
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One-pot synthesis of tertiary amines via borane-mediated reduction of imines and reductive N-alkylation with carbonyl compounds is described. This protocols reducing agent is only borane in the reduction of imines, and additional reductant is not necessary in reductive N-alkylation step. When using more than two equivalents of aldehydes, reductive N-alkylation proceeded in good yield.
- Tokizane, Masashi,Sato, Kaori,Sakami, Yuki,Imori, Yoichiro,Matsuo, Chika,Ohta, Tetsuo,Ito, Yoshihiko
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experimental part
p. 36 - 42
(2010/05/02)
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- Nitrosobenzene-mediated C-C bond cleavage reactions and spectral observation of an oxazetidin-4-one ring system
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While bond formation processes have traditionally garnered the attention of the chemical community, methods facilitating bond breaking remain relatively undeveloped. We report a novel, transition-metal-free oxidative C-C bond cleavage process for a broad range of ester and dicarbonyl compounds involving carbanion addition to nitrosobenzene. ReactIR experiments on the nitrosobenzene-mediated oxidative decarboxylation of esters indicate the reaction proceeds via fragmentation of a previously unobserved oxazetidin-4-one heterocycle, characterized by an intense IR stretching frequency at 1846 cm-1. These mechanistic studies have allowed further expansion of this protocol to ketone cleavage reactions of a diverse array of β-ketoester and 1,3-diketone substrates. The conceptual and mechanistic insights offered by this study are likely to provide a platform for further development of bond-breaking methodologies. Copyright
- Payette, Joshua N.,Yamamoto, Hisashi
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supporting information; experimental part
p. 12276 - 12278
(2009/02/05)
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- Palladium-catalyzed amination of aryl and heteroaryl tosylates at room temperature
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Mild palladium-catalyzed aminations of aryl tosylates and the first aminations of heteroaryl tosylates are described. In the presence of the combination of L2Pd(0) (L = P(o-tol)3) and the hindered Josiphos ligand CyPF-t-Bu, a variety of primary alkylamines and arylamines react with both aryl and heteroaryl tosylates at room temperature to form the corresponding secondary arylamines in high yields with complete selectivity for the monoarylamine. These reactions at room temperature occur in many cases with catalyst loadings of 0.1 mol % and 0.01 mol % in one case, constituting the most efficient aminations of aryl tosylates by nearly 2 orders of magnitude. This catalyst is made practical by the development of a convenient method to synthesize the L2Pd(0) precursor. This complex is stable to air as a solid. In contrast to conventional relative rates for reactions of aryl sulfonates, the reactions of aryl tosylates are faster than parallel reactions of aryl triflates, and the reactions of aryl tosylates are faster than parallel or competitive reactions of aryl chlorides. Copyright
- Ogata, Tokutaro,Hartwig, John F.
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supporting information; experimental part
p. 13848 - 13849
(2009/02/07)
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- IRON-COPPER CO-CATALYZED PROCESS FOR CARBON-CARBON OR CARBON-HETEROATOM BONDING
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The present invention relates to a process for creating a Carbon-Carbon bond (C-C) or a Carbon-Heteroatom bond (C -HE) by reacting a compound carrying a leaving group with a nucleophilic compound carrying a carbon atom or a heteroatom (HE) that can substitute for the leaving group, creating a C-C or C-HE bond, wherein the reaction takes place in the presence of an effective quantity of a catalytic system comprising iron and copper.
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Page/Page column 51-52
(2008/06/13)
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- Chiral ligands and their transition metal complexes
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The present invention relates to chiral phosphorus compounds and their transition metal complexes, and also to the use of these transition metal complexes, especially in asymmetric syntheses.
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- Base-induced rearrangement of tritylamines to imines: discovery and investigation of the mechanism
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An unexpected compound, the aniline derived benzophenone imine, was isolated when tritylamine was treated with n-BuLi and alkyl halides, during the formation of N-alkyl tritylamines, in the process of preparing primary amines. A nucleophilic attack of the nitrogen anion of tritylamide on the adjacent C-bonded phenyl, either substituted or not, involving a bridging anionic intermediate, is proposed for this base-induced tritylamine rearrangement to produce the corresponding imine. Electron-withdrawing groups in the aromatic ring, favoring the negative charge development, affect the relative migratory tendencies.
- Theodorou, Vassiliki,Skobridis, Konstantinos,Karkatsoulis, Aris
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p. 4284 - 4289
(2007/10/03)
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- N-substituted imines by the copper-catalyzed N-imination of boronic acids and organostannanes with O-acyl ketoximes
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Catalytic quantities of copper(I) or copper(II) sources catalyze the N-imination of boronic acids and organostannanes through reaction with oxime O-carboxylates under nonbasic conditions. This method tolerates various functional groups and takes place efficiently using aryl, heteroaryl, and alkenyl boronic acids and stannanes.
- Liu, Songbai,Yu, Ying,Liebeskind, Lanny S.
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p. 1947 - 1950
(2008/02/02)
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- Rhenium-catalyzed synthesis of naphthalene derivatives via insertion of aldehydes into a C-H bond
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A rhenium complex, [ReBr(CO)3(THF)]2, catalyzed reactions of aromatic ketimines and aldehydes with dienophiles, followed by dehydration, to give naphthalene derivatives in good to excellent yields. This reaction proceeds via C-H bond activation, insertion of an aldehyde, intramolecular nucleophilic cyclization, reductive elimination, elimination of aniline and Diels-Alder reaction. After dehydration, naphthalene derivatives were formed.
- Kuninobu, Yoichiro,Nishina, Yuta,Takai, Kazuhiko
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p. 8463 - 8468
(2008/02/09)
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- Reactions of aniline with alkali metal diphenylketyls and dianions derived from benzophenone and Michler's ketone
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Potassium diphenylketyl and benzophenone dianion react with aniline to afford N-(diphenylmethylene) aniline. Under analogous conditions, the corresponding sodium and lithium derivatives undergo disproportionation with formation of triphenylmethanol, benzo
- Turaeva,Kurbatov
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p. 1787 - 1790
(2007/10/03)
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- Solvent free amination reactions of aryl bromides at room temperature catalyzed by a (π-allyl)palladium complex bearing a diphosphinidenecyclobutene ligand
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An air- and moisture-stable (π-allyl)palladium complex bearing a unique diphosphinidenecyclobutene ligand effectively catalyzes amination reactions of aryl bromides with amines, where the reactions proceed under mild conditions without solvent, with 2 mol % of catalyst and 1 equiv of t-BuOK at room temperature. Under these conditions the amination products were obtained in good to excellent isolated yields.
- Gajare, Anil S.,Toyota, Kozo,Yoshifuji, Masaaki,Ozawa, Fumiyuki
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p. 6504 - 6506
(2007/10/03)
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- Synthesis of β-lactams and β-aminoesters via high intensity ultrasound-promoted Reformatsky reactions
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Reformatsky reactions of an imine, an α-bromoester, zinc dust and a catalytic amount of iodine in dioxane under high intensity ultrasound (HIU) irradiation from an ultrasonic probe are explored. A series of 16 aldimines with varying electronic demands is
- Ross, Nathan A.,MacGregor, Robert R.,Bartsch, Richard A.
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p. 2035 - 2041
(2007/10/03)
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- Ruthenium-catalyzed transfer hydrogenation of imines by propan-2-ol in benzene
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Transfer hydrogenation of a variety of different imines to the corresponding amines by propan-2-ol in benzene catalyzed by [Ru2(CO)4(μ H)(C4Ph4COHOCC4Ph4)] (1) has been studied. The reaction is highly efficient with turnover frequencies of over 800 per hour, and the product amines were obtained in excellent yields. A remarkable concentration dependence of propan-2-ol was observed when the reaction was run in benzene as cosolvent. An optimum was obtained at 24 equivalents of propan-2-ol to imine, and further increase of the propan-2-ol led to a dramatic decrease in rate. Also the use of polar cosolvents with 24 equivalents of propan-2-ol gave a low rate. It was found that ketimines react faster than aldimines and that electron-donating substituents on the imine increase the rate of the catalytic transfer hydrogenation. Electron-withdrawing substituents decreased the rate. An isomerization was observed with imines having an α-hydrogen at the N-alkyl substituent, which is in accordance with a mechanism involving a ruthenium-amine intermediate. It was demonstrated that the ruthenium-amine complex from α-methylbenzylamine, corresponding to the postulated intermediate, can replace 1 as catalyst in the transfer hydrogenation of imines. A primary deuterium isotope effect of kCH/CD = 2.7 ± 0.25 was observed when 2-deuterio-propan-2-ol vas used in place of propan-2-ol in the ransfer hydrogenation of N-phenyl-(1-phenylethylidene)amine.
- Samec, Joseph S. M.,Baeckvall, Jan-E.
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p. 2955 - 2961
(2007/10/03)
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- A new intramolecular migration of the imino group of O-arylketoximes to the aryl group under the Beckmann condition
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ZrCl4-mediated decomposition of O-arylketoximes in benzene leads to regioselective intramolecular migration of the imino group from the oxygen to the ortho position of the aryl group via electron-deficient nitrogen intermediates.
- Kikugawa, Yasuo,Tsuji, Chiho,Miyazawa, Etsuko,Sakamoto, Takeshi
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p. 2337 - 2339
(2007/10/03)
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- Amination reactions of aryl halides with nitrogen-containing reagents mediated by palladium/imidazolium salt systems
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Nucleophilic N-heterocyclic carbenes have been conveniently used as catalyst modifiers in amination reactions involving aryl chlorides, aryl bromides, and aryl iodides with various nitrogen-containing substrates. The scope of a coupling process using a Pd(0) or Pd(II) source and an imidazolium salt in the presence of a base, KOtBu or NaOH, was tested using various substrates. The Pd2(dba)3/IPr·HCl (1, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) system presents the highest activity with respect to electron-neutral and electron-rich aryl chlorides. The ligand is also effective for the synthesis of benzophenone imines, which can be easily converted to the corresponding primary amines by acid hydrolysis. Less reactive indoles were converted to N-aryl-substituted indoles using as supporting ligand the more donating SIPr·HCl (5, SIPr = 1,3-bis(2,6-diisopropylphenyl)-4,5-dihydroimidazol-2-ylidene). The Pd(OAc)2/SIPr·HCl/NaOH system is efficient for the N-arylation of diverse indoles with aryl bromides. The general protocol developed has been applied successfully to the synthesis of a key intermediate in the synthesis of an important new antibiotic. Mechanistically, palladium-to-ligand ratio studies strongly support an active species bearing one nucleophilic carbene ligand.
- Grasa,Viciu,Huang,Nolan
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p. 7729 - 7737
(2007/10/03)
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