- Mechanism of metabolic activation of the analgetic bucetin to bacterial mutagens by hamster liver microsomes
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Bucetin (N-(β-hydroxybutyryl)-p-phenetidine) was found to be mutagenic to Salmonella typhimurium TA100 in the presence of liver 9000 g supernatant fractions (S9) prepared from polychlorinated biphenyl (PCB)-treated hamsters and a reduced nicotinamide adenine dinucleotidephosphate (NADPH)-generating system. However, the analgetic was not mutagenic in the presence of NADPH-fortified S9 from PCB-treated rat liver. The mutagenic potency of bucetin was about a quarter of that of the structurally related analgetic, phenacetin. PCB-treated hamster liver microsomes fortified with NADPH activated bucetin to two direct-acting mutagens, N-hydroxy-phenetidine and p-nitrosophenetole, through deacylation followed by N-hydroxylation. The nitroso compound arose from N-hydroxyphenetidine via autoxidation. N-(b-Hydroxybutyryl)-p-amino-phenol, a major metabolite of bucetin under the conditions used, was not mutagenic to TA100 either with or without NADPH-fortified S9 from PCB-treated or untreated rats or hamsters. N-Hydroxybucetin, which was about 70 times less mutagenic than N-hydroxyphenacetin in the presence of PCB-treated hamster S9, was not detected as a metabolite of bucetin from the NADPH-fortified reaction mixtures. Although no species difference was observed in p-phenetidine N-hydroxylation, the rate of bucetin deacylation was over 90 times higher in hamsters than in rats. The rate of microsomal deacylation of bucetin was much lower than that of phenacetin or N-butyryl-p-phenetidine. These results suggest that the species difference in bucetin mutagenicity is due to the difference in deacylating activity between rat and hamster liver microsomes, and also that the β-hydroxyl group in the butyryl side chain makes bucetin poorly hydrolyzable in microsomes, resulting in lower mutagenic activity as compared with phenacetin.
- Nohmi,Ishidate Jr.,Hiratsuka,Watabe
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Read Online
- Effect of Meta and Para Substituents on the Stannous Chloride Reduction of Nitrobenzenes in Aqueous Ethanol
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The rate of reduction of 24 meta- and para-substituted nitrobenzenes with SnCl2 catalyzed by HCl in ethanol-water (90 : 10 v/v) at 30 degC has been measured iodometrically.The rate is expressed as υ = kst0.5, suggesting that the sole active reducing species is SnCl3- and the dissociation of HCl is very small.The effect of meta and para substituents in which the solvation of the substituent is taken into account was examined with the Hammett equation, which gave a ρ value of 2.1 +/- 0.1.Yukawa-Tsuno and Taft equations, in which resonance and inductive effects are separated, are also discussed.
- Xing, Wen-Kang,Ogata, Yoshiro
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Read Online
- Colloid and nanosized catalysts in organic synthesis: V. Reactions of alkyl halides and alcohols with ?2-diketones in the presence of metal nanoparticles
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Reaction of copper, nickel, and iron nanoparticles with ?2-diketones directly yields corresponding metal ?2-diketonates. Reaction of alkyl halides, ?2-diketones, and nanodispersed metals leads to a mixture of monoketone and the alkylated ?2-diketone. When alcohol is used as the alkylating agent instead of alkyl halide, corresponding ester is formed.
- Popov,Mokhov
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Read Online
- Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
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Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.
- Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 1618 - 1629
(2021/01/25)
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- Selective reduction of nitro-compounds to primary amines by tetrapyridinoporphyrazinato zinc (II) supported on DFNS
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Here, we created and synthesized a heterogeneous catalyst from porphyrazinatozinc (tmtppa-Zn) supported on DFNS (tmtppa-Zn/DFNS). This is a simple method for hydrogenation of nitro-compounds and their conversion to primary amines without producing toxic by-products. These reactions take place under mild reaction situations. The catalyst system was comfortably retrieved and reutilized in at least ten runs without the reduction of catalytic activity.
- Hosseiny, Malihesadat,Khosroyar, Susan,Kiani, Zahra,Motavalizadehkakhky, Alireza,Zhiani, Rahele
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- Mechanochemical Transformation of CF3 Group: Synthesis of Amides and Schiff Bases
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We communicate two mild, solvent-free mechanochemical coupling transformations of CF3 group with nitro compounds into amides or Schiff bases employing Ytterbia as a catalyst. This process proceeds via C?F bond activation, accompanied with utilisation of Si-based reductants/oxygen scavengers – reductants of the nitro group. The scope and limitations of the disclosed methodologies are thoroughly studied. To the best of our knowledge, this work is the first example of mechanical energy promoted transformation of the inert CF3 group into other functionalities. (Figure presented.).
- Mkrtchyan, Satenik,Jakubczyk, Micha?,Lanka, Suneel,Yar, Muhammad,Ayub, Khurshid,Shkoor, Mohanad,Pittelkow, Michael,Iaroshenko, Viktor O.
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supporting information
p. 5448 - 5460
(2021/10/19)
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- Green synthesis method of p-aminophenetole
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The invention relates to a green synthesis method of p-aminophenetole, and belongs to the field of preparation methods of chemical products. The synthesis method mainly comprises the following steps:adding raw material p-nitrophenetole into a reduction reaction kettle, performing a hydrogenation reduction reaction under the conditions of no solvent and Raney nickel as a catalyst, after the reaction is finished, cooling, filtering at normal pressure to recover the catalyst, and performing negative-pressure rectification on filtrate to obtain p-aminophenetole. The solvent-free technological conditions are adopted in the whole process, and emission of organic matters in a traditional production process is reduced; the problem that solvents such as methanol are subjected to reaction with reduced amino to generate carbaryl by-products is solved, and the product purity is improved; compared with a conventional solvent method, the green synthesis method has the advantages of lower temperature and lower energy consumption, reduces the production cost, and facilitates energy conservation and emission reduction.
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Paragraph 0005; 0008-0010
(2020/02/10)
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- Superior activity and selectivity of heterogenized cobalt catalysts for hydrogenation of nitroarenes
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The development of improved catalysts for highly selective hydrogenation of nitroarenes is described. For this purpose Co nanoparticles were supported on ordered mesoporous carbon CMK-3 and characterized in detail. The optimal CMK-3-CoPc catalyst exhibits excellent hydrogenation activity for several (hetero)aromatic nitro compounds and yielded the corresponding anilines under mild conditions (40 °C, 20 bar H2).
- Li, Wu,Artz, Jens,Broicher, Cornelia,Junge, Kathrin,Hartmann, Heinrich,Besmehn, Astrid,Palkovits, Regina,Beller, Matthias
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p. 157 - 162
(2019/01/10)
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- Reversible Formation of a Light-Responsive Catalyst by Utilizing Intermolecular Cooperative Effects
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A photoresponsive system where structure formation is coupled to catalytic activity is presented. The observed catalytic activity is reliant on intermolecular cooperative effects that are present when amphiphiles assemble into vesicular structures. Photoresponsive units within the amphiphilic pre-catalysts allow for switching between assembled and disassembled states, thereby modulating the catalytic activity. The ability to reversibly form cooperative catalysts within a dynamic self-assembled system represents a conceptually new tool for the design of complex artificial systems in water.
- Ren, Chloe Z.-J.,Solís Mu?ana, Pablo,Dupont, Julien,Zhou, Silvia Siru,Chen, Jack L.-Y.
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supporting information
p. 15254 - 15258
(2019/10/22)
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- Novel Biomass-Derived Fe3O4@Pd NPs as Efficient and Sustainable Nanocatalyst for Nitroarene Reduction in Aqueous Media
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Abstract: A novel magnetically recyclable nitrogen-doped Fe3O4@Pd NPs was prepared from the biomass-based materials which was employed as carbon and nitrogen source. The as-prepared catalysts were fully characterized by a variety of physicochemical techniques and were exploited for nitroaromatic hydrogenation with broad scope and excellent chemoselectivity using molecular hydrogen as a reductant. The heterogeneous catalysts can be recovered easily and reused for at least eight recycling reactions without obviously loss of catalytic properties. In addition, using this protocol, the key intermediate of marketed drug Osimertinib could be synthesized easily. Graphical Abstract: [Figure not available: see fulltext.].
- Zhao, Linwei,Zheng, Kai,Tong, Jianying,Jin, Jianzhong,Shen, Chao
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p. 2607 - 2613
(2019/06/08)
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- A new alkylation of aryl alcohols by boron trifluoride etherate
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The ethylation of aryl alcohols by an ethyl moiety of boron trifluoride etherate is described. The reaction proceeded cleanly and afforded good yields of the corresponding aryl ethyl ethers. It tolerated the presence of functional groups such as aryl, alkyl, halogens, nitro, nitrile, and amino. However, the presence of amino or nitro groups ortho to a hydroxyl group of an aryl compound drastically reduced the yields of the anticipated products due to the chelation of the aforementioned functional groups with boron trifluoride etherate. A nitrogen atom in the aromatic ring system, as exemplified by hydroxypyridine and 8-hydroxyquinoline, completely inhibited the reaction. Resorcinol, hydroquinone, and aryl alcohols with aldehyde functions decomposed under the reaction conditions.
- Jumbam, Ndze Denis,Maganga, Yamkela,Masamba, Wayiza,Mbunye, Nomthandazo I.,Mgoqi, Esethu,Mtwa, Sphumusa
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- Application of Silicon-Initiated Water Splitting for the Reduction of Organic Substrates
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The use of water as a donor for hydrogen suitable for the reduction of several important classes of organic compounds is described. It is found that the reductive water splitting can be promoted by several metalloids among which silicon shows the best efficiency. The developed methodologies were applied for the reduction of nitro compounds, N-oxides, sulfoxides, alkenes, alkynes, hydrodehalogenation as well as for the gram-scale synthesis of several substrates of industrial importance.
- Gevorgyan, Ashot,Mkrtchyan, Satenik,Grigoryan, Tatevik,Iaroshenko, Viktor O.
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p. 375 - 382
(2018/06/04)
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- NITROGEN-CONTAINING BIOPOLYMER-BASED CATALYSTS, THEIR PREPARATION AND USES IN HYDROGENATION PROCESSES, REDUCTIVE DEHALOGENATION AND OXIDATION
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The present invention relates to a process for the preparation of a nitrogen containing biopolymer-based catalyst by pyrolysis of a metal complex with a nitrogen-containing biopolymer and to the nitrogen containing biopolymer-based catalysts obtainable by this process. In particular, the invention relates to a nitrogen containing biopolymer-based catalyst comprising metal particles and at least one nitrogen containing carbon layer. The invention also relates to the use of a nitrogen containing biopolymer-based catalyst in a hydrogenation process, preferably in a process for hydrogenation of nitroarenes, nitriles or imines; in a reductive dehalogenation process of C-X bonds, wherein X is CI, Br or I, preferably in a process for dehalogenation of organohalides or in a process for deuterium labelling of arenes via dehalogenation of organohalides; or in an oxidation process. Further, the invention relates to a metal complex with the nitrogen containing biopolymer, wherein the metal is a transition metal selected from the group consisting of manganese, ruthenium, cobalt, rhodium, nickel, palladium and platinum, preferably cobalt or nickel, and wherein the nitrogen containing biopolymer is selected from chitosan, chitin and a polyamino acid, preferably chitosan or chitin.
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Page/Page column 16; 31-32
(2018/07/29)
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- Investigation of hydro-lipophilic properties of n-alkoxyphenylhydroxynaphthalenecarboxamides ?
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The evaluation of the lipophilic characteristics of biologically active agents is indispensable for the rational design of ADMET-tailored structure–activity models. N-Alkoxy-3-hydroxynaphthalene-2-carboxanilides, N-alkoxy-1-hydroxynaphthalene-2-carboxanilides, and N-alkoxy-2-hydroxynaphthalene-1-carboxanilides were recently reported as a series of compounds with antimycobacterial, antibacterial, and herbicidal activity. As it was found that the lipophilicity of these biologically active agents determines their activity, the hydro-lipophilic properties of all three series were investigated in this study. All 57 anilides were analyzed using the reversed-phase high-performance liquid chromatography method for the measurement of lipophilicity. The procedure was performed under isocratic conditions with methanol as an organic modifier in the mobile phase using an end-capped non-polar C18 stationary reversed-phase column. In the present study, a range of software lipophilicity predictors for the estimation of clogP values of a set of N-alkoxyphenylhydroxynaphthalenecarboxamides was employed and subsequently cross-compared with experimental parameters. Thus, the empirical values of lipophilicity (logk) and the distributive parameters (π) were compared with the corresponding in silico characteristics that were calculated using alternative methods for deducing the lipophilic features. To scrutinize (dis)similarities between the derivatives, a PCA procedure was applied to visualize the major differences in the performance of molecules with respect to their lipophilic profile, molecular weight, and violations of Lipinski’s Rule of Five.
- Kapustikova, Iva,Bak, Andrzej,Gonec, Tomas,Kos, Jiri,Kozik, Violetta,Jampilek, Josef
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- Doped ordered mesoporous carbons as novel, selective electrocatalysts for the reduction of nitrobenzene to aniline
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Ordered mesoporous carbons (OMCs) doped with nitrogen, phosphorus or boron were synthesised through a two-step nanocasting method and studied as electrocatalysts for the reduction of nitrobenzene to aniline in a half-cell setup. The nature of the dopant played a crucial role in the electrocatalytic performance of the doped OMCs, which was monitored by LSV with a rotating disk electrode setup. The incorporation of boron generated the electrocatalysts with the highest kinetic current density, whereas the incorporation of phosphorus led to the lowest overpotential. Doping with nitrogen led to intermediate behaviour in terms of onset potential and kinetic current density, but provided the highest selectivity towards aniline, thus resulting in the most promising electrocatalyst developed in this study. Density functional theory calculations allowed explaining the observed difference in the onset potentials between the various doped OMCs, and indicated that both graphitic N and pyrdinic N can generate active sites in the N-doped electrocatalyst. A chronoamperometric experiment over N-doped OMC performed at -0.75 V vs. Fc/Fc+ in an acidic environment, resulted in a conversion of 61% with an overall selectivity of 87% to aniline. These are the highest activity and selectivity ever reported for an electrocatalyst for the reduction of nitrobenzene to aniline, making N-doped OMC a promising candidate for the electrochemical cogeneration of this industrially relevant product and electricity in a fuel cell setup.
- Daems, Nick,Risplendi, Francesca,Baert, Kitty,Hubin, Annick,Vankelecom, Ivo F. J.,Cicero, Giancarlo,Pescarmona, Paolo P.
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supporting information
p. 13397 - 13411
(2018/07/25)
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- Synthesis and mesomorphic properties of 2,4-bis(4′-n-pentyloxybenzoyloxy)- benzylidine-4″- n-alkoxyaniline
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The synthesis and mesomorphic properties of a new series of 2,4-bis(4′-npentyloxybenzoyloxy)- benzylidine-4″ -n-alkoxyaniline (DC5An) are reported. The molecular structure of compounds was confirmed by FTIR, 1H-NMR, 13C-NMR, mass spectroscopy and elemental analysis. The mesomorphic properties were studied by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) measurements. All compounds of the series exhibit nematic (N) and smectic C (SmC) phases. The first four homologues (DC5A1-DC5A4) display a N mesophase, whereas the highest homologues (DC5A5-DC5A10) exhibit an enantiotropic dimorphism N and SmC phases. The mesomorphic properties of the present series are compared and discussed with other structurally related series.
- Hamad, Wali M.,Azeez, Hashim J.,Al-Dujaili, Ammar H.
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- Biomass-Derived Catalysts for Selective Hydrogenation of Nitroarenes
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Development of catalytically active materials from biowaste represents an important aspect of sustainable chemical research. Three heterogeneous materials were synthesized from inexpensive biomass-based chitosan and abundant Co(OAc)2 using complexation followed by pyrolysis at various temperatures. These materials were applied in the catalytic hydrogenation of nitroarenes using molecular hydrogen. A variety of diversely functionalized nitroarenes including some pharmaceutically active compounds were converted into aromatic amines in high yields, with high selectivity, and with excellent functional group tolerance. This green protocol has also been implemented for the synthesis of a biologically important TRPC3 inhibitor.
- Sahoo, Basudev,Formenti, Dario,Topf, Christoph,Bachmann, Stephan,Scalone, Michelangelo,Junge, Kathrin,Beller, Matthias
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p. 3035 - 3039
(2017/08/18)
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- The heliconical nematic twist-bend phase from “classic” bent-core benzylideneanilines with oligomethylene cores
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We report the synthesis and properties of several new heliconical twist-bend nematic (NTB) bimesogens possessing “classic” bent-core benzylideneaniline wings combined with oligomethylene spacers of odd parity. While short alkoxy tails combined with a resorcinol diester core in the classic system appear to give SmA phases (not B2 phases), in the present system, methoxy or ethoxy tails exhibit the NTB phase as evidenced by textural analysis. Several of these compounds also exhibit microscopic helical defect structures in the NTB phase, which have been reported in other lamellar and pseudo-lamellar liquid crystal phases, but not in the NTB phase.
- Scarbrough, Alyssa N.,Tuchband, Michael R.,Korblova, Eva D.,Shao, Renfan,Shen, Yongqiang,Maclennan, Joseph E.,Glaser, Matt A.,Clark, Noel A.,Walba, David M.
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p. 430 - 438
(2017/05/26)
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- Formal arylation of NH3 to produce diphenylamines over supported Pd catalysts
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In the presence of supported Pd nanoparticle catalysts, e.g., Pd/Al2O3, various diphenylamines could be synthesized through acceptorless formal arylation using NH3 or its surrogates, e.g., urea, as nitrogen sources and cyclohexanones as arylation sources. The observed catalysis was truly heterogeneous, and the catalyst was reusable with retention of its high catalytic performance.
- Koizumi, Yu,Taniguchi, Kento,Jin, Xiongjie,Yamaguchi, Kazuya,Nozaki, Kyoko,Mizuno, Noritaka
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supporting information
p. 10827 - 10830
(2017/10/09)
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- Direct Hydrogenation of a Broad Range of Amides under Base-free Conditions using an Efficient and Selective Ruthenium(II) Pincer Catalyst
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The ruthenium(II) complex, [fac-PNHN]RuH(η1-BH4)(CO) (B; PNHN=8-(2-diphenylphosphinoethyl)aminotrihydroquinoline), is a highly versatile and effective catalyst (loadings of 0.1–1 mol %) for the hydrogenation of a multitude of amides, which include primary, secondary, and tertiary amides, to give their corresponding alcohols and amines in high yields under base-free conditions. All products were confirmed by using GC and GC–MS.
- Wang, Zheng,Li, Yong,Liu, Qing-Bin,Solan, Gregory A.,Ma, Yanping,Sun, Wen-Hua
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p. 4275 - 4281
(2017/12/02)
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- Fe-Catalyzed Amination of (Hetero)Arenes with a Redox-Active Aminating Reagent under Mild Conditions
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A novel and efficient Fe-catalyzed direct C?H amination (NH2) of arenes is reported using a new redox-active aminating reagent. The reaction is simple, and can be performed under air, mild, and redox-neutral conditions. This protocol has a broad substrate scope and could be used in the late-stage modification of bioactive compounds. Mechanistic studies demonstrate that a radical pathway could be involved in this transformation.
- Liu, Jianzhong,Wu, Kai,Shen, Tao,Liang, Yujie,Zou, Miancheng,Zhu, Yuchao,Li, Xinwei,Li, Xinyao,Jiao, Ning
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supporting information
p. 563 - 567
(2017/01/18)
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- Properties of liquid crystals and Cu2+ recognition based on Schiff bases
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Two series of new Schiff base compounds were synthesized. For Schiff base compounds with a pyridine nitrogen atom in 4-position (7a-e), their supramolecular hydrogen bonding complexes show good liquid crystal properties. However, no liquid crystal property is observed for 8a-e. Results of theoretical calculations demonstrate that it is the intermolecular hydrogen bond of Schiff base compounds (8a-e) that prevents the formation of supramolecular hydrogen bonding. The Schiff base compounds, with terminal alkoxy chains, can recognize Cu2+ selectively with a color change. Nevertheless, others cannot recognize Cu2+.
- Liu, Zhilian,Yu, Zhenning,Zhang, Jian,Zhang, Shuxiang
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- Fe2O3/NGr@C- and Co-Co3O4/NGr@C-catalysed hydrogenation of nitroarenes under mild conditions
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An improved hydrogenation of nitroarenes using nano-structured iron- and cobalt-based catalysts is presented. Modifications of the heterogeneous catalysts by N-doped graphene-flakes are crucial for the success of selective reductions. The use of polar solvents and basic additives has a significant positive influence on the rate of reduction of nitroarenes. This allows performing non-noble metal-catalysed hydrogenations under very mild reaction conditions (e.g. 70 °C and 20 bar). On the basis of the obtained catalytic results a heterolytic mechanism for the hydrogenation process is postulated, too.
- Formenti, Dario,Topf, Christoph,Junge, Kathrin,Ragaini, Fabio,Beller, Matthias
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p. 4473 - 4477
(2016/07/06)
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- Intermolecular C–O Coupling Using Hemicucurbituril Supported Ionic Liquid Phase Catalyst
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Abstract: Hemicucurbituril supported ionic liquid phase catalyst (HmCucSILP) has been synthesized by anchoring multilayer of ionic liquid ([Bmim]Cl) containing Pd(OAc)2 and X-phos on the surface of hemicucurbit[6]uril. The HmCucSILP was effectively employed in intermolecular C–O coupling of aryl halides with sodium alkoxides for the synthesis of alkyl aryl ethers. Graphical Abstract: [Figure not available: see fulltext.]
- Kurane, Rajanikant,Bansode, Prakash,Khanapure, Sharanabasappa,Kale, Dolly,Salunkhe, Rajashri,Rashinkar, Gajanan
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p. 2485 - 2494
(2016/11/25)
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- Direct synthesis of anilines and nitrosobenzenes from phenols
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A one-pot synthesis of anilines and nitrosobenzenes from phenols has been developed using an ipso-oxidative aromatic substitution (iSOAr) process. The products are obtained in good yields under mild and metal-free conditions. The leaving group effect on reactions that proceed through mixed quionone monoketals has also been investigated and a predictive model has been established.
- St Amant,Frazier,Newmeyer,Fruehauf,Read De Alaniz
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p. 5520 - 5524
(2016/07/06)
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- Green synthesis of silver nanoparticles using Terminalia cuneata and its catalytic action in reduction of direct yellow-12 dye
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Facile green synthesis of silver nanoparticles (AgNPs) using aqueous bark extract of Terminalia cuneata has been reported in this article. The effects of concentration of the extract, reaction time and pH were studied by UV-Vis spectroscopy. Appearance of yellow color with λmax around ~ 420 nm suggested the formation of AgNPs. The stable AgNPs were further characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS) with zeta potential and high resolution transmission electron microscopy (HR-TEM) with energy dispersive X-ray spectroscopy (EDS) analysis. The synthesized AgNPs were in the size range of 25-50 nm with a distorted spherical shape identified from HR-TEM analysis. The catalytic activity of AgNPs on the reduction of direct yellow-12 using NaBH4 was analyzed using a UV-Vis spectrophotometer. This study showed the efficacy of biogenic AgNPs in catalyzing the reduction of direct yellow-12.
- Edison, Thomas Nesakumar Jebakumar Immanuel,Lee, Yong Rok,Sethuraman, Mathur Gopalakrishnan
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p. 122 - 129
(2016/04/04)
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- Selective reduction of nitro-compounds to primary amines by nickel-catalyzed hydrosilylative reduction
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Ni(acac)2 and PMHS were found to be an excellent catalytic system for the chemoselective transfer hydrogenation of nitro-compounds to primary amines. Under mild conditions a series of nitro-compounds containing a variety of sensitive functional groups including aldehydes, esters, cyano, and nitrine were reduced to their corresponding amines in good to excellent yields with no byproduct.
- Sun, Shuai,Quan, Zhengjun,Wang, Xicun
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p. 84574 - 84577
(2015/10/28)
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- Synthesis and Biological Evaluation of N-Alkoxyphenyl-3-hydroxynaphthalene-2-carboxanilides
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A series of fifteen new N-alkoxyphenylanilides of 3-hydroxynaphthalene-2-carboxylic acid was prepared and characterized. Primary in vitro screening of the synthesized compounds was performed against Staphylococcus aureus, three methicillin-resistant S. aureus strains, Mycobacterium tuberculosis H37Ra and M. avium subsp. paratuberculosis. Some of the tested compounds showed antibacterial and antimycobacterial activity against the tested strains comparable with or higher than that of the standards ampicillin or rifampicin. 3-Hydroxy-N-(2-propoxyphenyl)naphthalene-2-carboxamide and N-[2-(but-2-yloxy)-phenyl]-3-hydroxynaphthalene-2-carboxamide had MIC = 12 μM against all methicillin-resistant S. aureus strains; thus their activity is 4-fold higher than that of ampicillin. The second mentioned compound as well as 3-hydroxy-N-[3-(prop-2-yloxy)phenyl]-naphthalene-2-carboxamide had MICs = 23 μM and 24 μM against M. tuberculosis respectively. N-[2-(But-2-yloxy)phenyl]-3-hydroxynaphthalene-2-carboxamide demonstrated higher activity against M. avium subsp. paratuberculosis than rifampicin. Screening of the cytotoxicity of the most effective antimycobacterial compounds was performed using THP-1 cells, and no significant lethal effect was observed for the most potent compounds. The compounds were additionally tested for their activity related to inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. N-(3-Ethoxyphenyl)-3-hydroxynaphthalene-2-carboxamide (IC50 = 4.5 μM) was the most active PET inhibitor. The structure-activity relationships are discussed.
- Gonec, Tomas,Zadrazilova, Iveta,Nevin, Eoghan,Kauerova, Tereza,Pesko, Matus,Kos, Jiri,Oravec, Michal,Kollar, Peter,Coffey, Aidan,O'Mahony, Jim,Cizek, Alois,Kralova, Katarina,Jampilek, Josef
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p. 9767 - 9787
(2015/08/06)
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- Colloid and nanosized catalysts in organic synthesis: IV. Reduction of nitroarenes with hydrazine hydrate catalyzed with metal nanoparticles
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Reduction of a series of nitroarenes with hydrazine hydrate catalyzed with colloid iron, cobalt, nickel, and copper particles has been studied. High catalytic activity of nickel and iron nanoparticles has been demonstrated. Special features of nitrobenzene reduction in the presence of cobalt particles have been revealed.
- Mokhov, V. M.,Popov, Yu. V.,Nebykov, D. N.
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p. 1515 - 1518
(2014/12/10)
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- Liquid-crystalline polymorphism of 4-heptyloxybenzylidene-4′- alkyloxyanilines and their phase equilibrium with 4-octyloxyphenyl 4-nitrobenzoate
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This paper describes the synthesis and liquid-crystalline properties of the homologous series of 4-heptyloxybenzylidene-4′-alkyloxyanilines (7-n). Six of them are presented for the first time. Based on the polarization microscopy (POM and TOA methods) and the calorimetric (DSC) measurements following polymorphism has been detected: nematic, smectic C and smectic I mesophases. The presence of these mesophases was confirmed by the miscibility method, using 4-octyloxyphenyl 4-nitrobenzoate and terephtal-bis (4-butyloaniline) as a mesophase references. Extraordinary results have been found in the mixtures of the investigated compounds with 4-octyloxyphenyl 4-nitrobenzoate; Induced smectic A has been observed, which is connected with very strong intermolecular interactions. Additionally destabilization of nematic and smectic C phases was visible.
- Godzwon, Joanna,Sienkowska, Monika J.,Galewski, Zbigniew
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scheme or table
p. 75 - 82
(2012/04/04)
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- Ruthenium nanoparticle-catalyzed, controlled and chemoselective hydrogenation of nitroarenes using ethanol as a hydrogen source
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This communication describes a ruthenium nanoparticle-catalyzed reduction of nitroarenes giving azoxyarenes, azoarenes, or anilines in good to excellent yields using ethanol as a hydrogen source. Copyright
- Kim, Ju Hyun,Park, Ji Hoon,Chung, Young Keun,Park, Kang Hyun
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supporting information
p. 2412 - 2418
(2012/11/07)
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- Mesoporous nitrogen doped nano titania - A green photocatalyst for the effective reductive cleavage of azoxybenzenes to amines or 2-phenyl indazoles in methanol
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A new nitrogen precursor, hydrazine hydrate was used in the synthesis of nano-sized, N-doped TiO2 photocatalyst by a simple wet impregnation method. This photocatalyst was characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), High resolution transmission electron microscope (HR-TEM), UV-vis diffuses reflectance spectra (DRS), photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS). XRD patterns show that the crystal structure of N-TiO2 resembles anatase phase of TiO2. The UV-vis spectra indicate an increase in absorption of visible light when compared to TiO2. Furthermore XPS analysis reveals the presence of the N atom as O-Ti-N linkage substituting the O atom in the TiO2 lattice and this causes a decrease in oxygen vacancies. N-TiO2 nanoparticles were used as a green and recyclable heterogeneous photocatalyst for rapid and efficient reductive cleavage of azoxybenzene into their corresponding amines or 2-phenylindazoles with methanol at room temperature under N2 atmosphere. Azoxybenzenes in neat methanol afforded anilines, while in aqueous methanol (20% water-80% methanol) they formed corresponding 2-phenyl indazoles. In both reductive cleavages, nano N-TiO2 is more effective than prepared TiO2, showing that the nitrogen doping could be an excellent choice to improve the photoactivity of TiO2.
- Selvam,Balachandran,Velmurugan,Swaminathan
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experimental part
p. 213 - 222
(2012/03/26)
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- Studies of calamitic liquid crystalline compounds involving ester-azo central linkages with a biphenyl moiety
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Two mesogenic homologous series involving ester-azo central linkages with a biphenyl moiety have been synthesized, such as 4'-[(4-n-alkoxyphenyl)diazenyl] biphenyl-4-ol (series I) and 4'-[(4-n-alkoxyphenyl) diazenyl]-4-butoxy phenyl biphenyl-4-carboxylate (series II). Azobiphenyl of series I having a free hydroxyl group with strong hydrogen bonding exhibits a high-temperature enantiotropic smectic phase. Whereas in series II, compounds containing C 1-C8 carbon atoms exhibit only a monotropic smectic phase and compounds with C10, C12, C14, and C 16 atoms show an enantiotropic smectic phase. These compounds were characterized by elemental analysis, FT-IR, 1H-NMR, and mass spectral studies. The phase transition and mesogenicity of these substances were studied by polarizing optical microscopic and differential scanning calorimetric techniques. Their thermal stabilities and other characteristics are discussed. Copyright Taylor &Francis Group, LLC.
- Thaker,Dhimmar,Patel,Solanki,Patel,Chothani,Kanojiya
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experimental part
p. 172 - 191
(2012/07/27)
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- Role of terminal heterocyclic ring on mesomorphic properties of homologous series
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Two new homologous series of compounds with a heterocyclic ring having sulfur and oxygen as a hetero atom derived from p-hydroxy acetophenone and alkoxy aniline containing cinnamate-azomethine as central linkages have been synthesized. viz. 4(furalacryloxy) α-methyl benzylidine-4′-alkoxy aniline and 4(thianylacryloxy) α-methyl benzylidine-4′-alkoxy aniline. The compound of both the series have been characterized by elemental analysis, FT-IR, 1H-NMR, and mass spectrometry method. Their liquid crystalline properties have been investigated by optical polarizing microscopy and differential scanning calorimetry (DSC) studies. All the derivatives are mesomorphic in nature showing the nemetic phase. The mesomorphic properties of the present two series are compared with other structurally related series to evaluate the effect of thiophene and furan on mesomorphism. Copyright Taylor & Francis Group, LLC.
- Thaker,Patel,Solanki,Dhimmer,Dave
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experimental part
p. 63 - 80
(2010/09/05)
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- Smectic polymorphism of 4-nonyloxybenzylidene-4′-alkyloxyanilines
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This paper describes liquid-crystalline polymorphism of the homologous series of 4-nonyloxybenzylidene-4′-alkyloxyanilines. Based on the polarization microscopy (POM, TOA) and the calorimetric (DSC) measurements the following mesophases were detected: nematic, smectic A, smectic C, smectic B, smectic I and smectic G. The presence of these mesophases was confirmed by the miscibility method, using: 4-heptyloxybenzilidene-4′-pentylaniline, 4-hexyl-4′-decyloxyazobenzene and 4-nonyloxybenzilidene-4′-butylaniline as mesophase references. Influence of the alkyl chain length on the type of mesophases and entropic effects of phase transition are discussed.
- Godzwon, Joanna,Sienkowska, Monika J.,Galewski, Zbigniew
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p. 259 - 267
(2008/03/13)
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- Structure-activity relationships in the binding of chemically derivatized CD4 to gp120 from human immunodeficiency virus
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The first step in HIV infection is the binding of the envelope glycoprotein gp120 to the host cell receptor CD4. An interfacial "Phe43 cavity" in gp120, adjacent to residue Phe43 of gp120-bound CD4, has been suggested as a potential target for therapeutic intervention. We designed a CD4 mutant (D1D2F43C) for site-specific coupling of compounds for screening against the cavity. Altogether, 81 cysteine-reactive compounds were designed, synthesized, and tested. Eight derivatives exceeded the affinity of native D1D2 for gp120. Structure-activity relationships (SAR) for derivatized CD4 binding to gp120 revealed significant plasticity of the Phe43 cavity and a narrow entrance. The primary contacts for compound recognition inside the cavity were found to be van der Waals interactions, whereas hydrophilic interactions were detected in the entrance. This first SAR on ligand binding to an interior cavity of gp120 may provide a starting point for structure-based assembly of small molecules targeting gp120-CD4 interaction.
- Xie, Hui,Ng, Danny,Savinov, Sergey N.,Dey, Barna,Kwong, Peter D.,Wyatt, Richard,Smith III, Amos B.,Hendrickson, Wayne A.
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p. 4898 - 4908
(2008/03/11)
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- A practical and selective reduction of nitroarenes using elemental sulfur and mild base
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A method was developed to reduce aromatic nitro compounds to the corresponding anilines using sulfur and base. The method tolerates a range of functional groups on the benzene ring, avoids the use of hydrogen and transition metals and provides the anilines in moderate to high yields.
- McLaughlin, Maureen A.,Barnes, David M.
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p. 9095 - 9097
(2007/10/03)
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- Liquid-liquid-liquid phase transfer catalysis: A novel and green concept for selective reduction of substituted nitroaromatics
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The selective reduction of nitroaromatics to the corresponding amines is an important transformation since many aromatic amines exhibit biological activities and find a multitude of industrial applications, being intermediates for the synthesis of dyes, pharmaceuticals and agrochemicals. A variety of nitroaromatics dissolved in organic solvents was reduced by using aqueous sodium sulfide, and tetrabutylammonium bromide (TBAB) as the phase transfer catalyst by choosing appropriate concentrations which resulted in three immiscible liquid phases. Compared to L-L PTC, the L-L-L PTC offers much higher rates of reaction, better selectivities and repeated use of catalyst. The selectivities for the desired products were 100%.
- Yadav, Ganapati D.,Lande, Sharad V.
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p. 1235 - 1241
(2007/10/03)
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- Amination of arenes with N,N-dimethyl-2-imidazolidinone O-methoxyacetyloxime
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Treatment of nucleophilic arenes with N,N-dimethyl-2imidazolidinone O-methoxyacetyloxime and SnCl4 produced the corresponding N-arylimines, which were converted to anilines by hydrolysis with CsOH and to N-methylanilines by LiAlH4 reduction.
- Baldovini, Nicolas,Kitamura, Mitsuru,Narasaka, Koichi
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p. 548 - 549
(2007/10/03)
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- Facile and selective cleavage of allyl ethers, amines and esters using polymethylhydrosiloxane-ZnCl2/Pd(PPh3)4
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Allyl deprotection to liberate free hydroxy, amino and acid groups from the corresponding allyl ethers, amines and esters is achieved under mild conditions. The reagent combination employed for this transformation is polymethylhydrosiloxane (PMHS), ZnCl2 and Pd(PPh3)4.
- Chandrasekhar,Raji Reddy,Jagadeeshwar Rao
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p. 3435 - 3438
(2007/10/03)
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- Process for the manufacture of P-phenetidine
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A process for the manufacture of para-phenetidine is described. The process comprises the following steps: (a) diazotizing para-phenetidine and coupling the resulting compound to phenol at a molar ratio of 1.3 to 1 phenol to the diazo compound;(b) ethylating the resulting compound at a temperature in the range of between 130°C to 200°C, and (c) catalytically hydrogenating the ethylated compound, whereby two moles of para-phenetidine are produced, one of which being recycled as the starting reagent in the first step. The product obtained is of a high purity being substantially free from the undesired isomers.
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- Process for the manufacture of p-phenetidine
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A process for the manufacture of para-phenetidine is described. The process comprises the following steps: (a) diazotizing para-phenetidine and coupling the resulting compound to phenol at a molar ratio of 1.3 to 1 phenol to the diazo compound;(b) ethylating the resulting compound at a temperature in the range of between 130° C. to 200° C., and (c) catalytically hydrogenating the ethylated compound, whereby two moles of para-phenetidine are produced, one of which being recycled as the starting reagent in the first step. The product obtained is of a high purity being substantially free from the undesired isomers.
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- The novel reduction systems: NaBH4-SbCl3 or NaBH4-BiCl3 for conversion of nitroarenes to primary amines
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Nitroarenes can be conveniently reduced to primary amines in good to excellent yields by sodium borohydride in the presence of bismuth chloride or antimony chloride.
- Ren,Pan,Dong,Wu
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p. 3799 - 3803
(2007/10/03)
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- Mesogenic 4-(2,3-Epoxypropoxy)-4'-alkoxyazoxybenzenes
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Optimal conditions for preparation of 4-(2,3-epoxypropoxy)-4'-alkoxyazoxybenzenes were developed, and 10 mesogenic homologs (n = 1-10) possessing an extended nematic mesophase were synthesized.Nonyloxy and decyloxy derivatives of epoxyazoxybenzene exhibit also smectic mesomorphism.
- Burmistrov, V. A.,Kuz'mina, S. A.,Koifman, O. I.
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p. 351 - 353
(2007/10/03)
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- Mesogenic properties of liquid crystals having a chiral semiflexible joint
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Two homologous series of mesogenic enantiomers with chiral semiflexible joint, -C*H(CH3)CH2COO-, are examined. High twist power and presence of blue phases with short lattice period are found for eleven examined compounds. Some effects of chirality in reentrant system are discussed. On phase diagram of enantiomers the SmAd phase area is shifted toward longer homologues as compared to racemates. In result, an island of the SmAd phase in the cholesteric sea exists on binary phase diagrams of R- and S- enantiomers. Triple divergence of the pitch in the cholesteric phase of a pure compound is observed.
- Gorecha,Pyzuk,Mieczkowski
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- Triphendioxazine dyestuffs
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The novel triphendioxazine dyestuffs of the formula STR1 in which the substituents R, R', T1, T2, X, Y and n have the meanings given in the description are highly suitable for the dyeing and printing of cellulose-containing or amido-containing material.
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- A Novel Synthesis of 2-Arylaminothiazolopyridazinones
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The reaction of 5(4)-amino-4(5)-chloropyridazin-3(2H)-ones 1 (9) with methyl dithiocarbamates 2 gave 2-arylaminothiazolopyridazinones 3 (10).Treatment of 5(4)-alkylamino-4(5)-chloropyridazin-3(2H)-ones 5 (12) with 2 afforded the corresponding 2-aryliminothiazolopyridazinones 6 (13).Cyclization of 1a with phenylisothiocyanate produced 2-amino- and 2-iminothiazolopyridazinones 3a and 16.
- Yamasaki, Tetsuo,Kawaminami, Eiji,Uchimura, Fumi,Okawara, Tadashi,Furukawa, Mitsuru
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p. 859 - 865
(2007/10/02)
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- KINETICS OF ALKALINE HYDROLYSIS AND CORRELETION STUDIES OF m- AND p-SUBSTITUTED PIPERIDINOETHYL PHENYLCARBAMATES
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Kinetics of alkaline hydrolysis have been studied with a series of 15 m- and p-substituted piperidinoethyl phenylcarbamates.The rate constants have been determined at 70, 60, 50, and 40 deg C and the activation parameters have been calculated.These values have been correlated with the substituent constants ?, , , F, R, ?.Validity of the Hammett equation and the Swain-Lupton equation has been confirmed in the series studied and for the p-derivatives, respectively.The lipophilicity parameter ? does not correlate with the values found.
- Stankovicova, Maria,Cizmarik, Jozef
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p. 1846 - 1853
(2007/10/02)
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- Alkali catalyzed thermal cyclization of 1-substituted and 1,6-disubstituted 2,5-dithiobiureas: Formation of 1,2,4-triazolidine-3,5-dithiones and/or 1,3,4-thiadiazoline-5-thiones
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Alkali catalyzed thermal cyclization of 1-alkyl and 1,6-dialkyl-2,5-dithiobiureas (I, R=alkyl, R'=H and R=R'=alkyl) results in the formation of 4-alkyl-1,2,4-triazolidine-3,5-dithiones (V) (alkyl=Me or Et) and 2-alkylamino-Δ2-1,3,4-thiadiazoline-5-thiones (VI) (alkyl=n-Pr or n-Bu).Under the same conditions, 1-alkyl-6-aryl-2,5-dithiobiureas (I, R=alkyl, R'=aryl) give 2-arylamino-Δ2-1,3,4-thiadiazoline-5-thiones (IX) (alkyl=Me, Et, n-Pr or n-Bu) and 4-alkyl-1,2,4-triazolidine-3,5-dithiones (V) also when the alkyl groups are Me or Et.
- Raphael, Elsamma,Joshua, C. P.,Koshy, Lisamma
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p. 635 - 638
(2007/10/02)
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