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100-01-6Relevant articles and documents
Development of chemoselective photoreduction of nitro compounds under solar light and blue LED irradiation
Zand, Zahra,Kazemi, Foad,Hosseini, Saber
, p. 338 - 341 (2014)
Solar light and blue light irradiation of the commercially available heterogeneous nano photocatalyst TiO2-P25 leads to reduction of nitro compounds to give the corresponding amines. The methodology provides a green and mild approach to this useful class of organic compounds. Aromatic nitro compounds containing a wide range of functional groups tolerated the conditions to give, chemoselectively the corresponding amines in excellent yields.
A new palladium complex supported on magnetic nanoparticles and applied as an catalyst in amination of aryl halides, Heck and Suzuki reactions
Ghorbani-Choghamarani, Arash,Tahmasbi, Bahman,Noori, Nourolah,Ghafouri-nejad, Raziyeh
, p. 681 - 693 (2017)
A simple, efficient and less expensive protocol for the phosphine-free C–C coupling reactions and synthesis of anilines in the presence of 2-aminobenzamide complex of palladium supported on Fe3O4 magnetic nanoparticles (Pd(0)-ABA-Fe3O4) has been reported. The Suzuki reaction was carried out in water or PEG using phenylboronic acid (PhB(OH)2) or sodium tetraphenyl borate (NaBPh4). Pd(0)-ABA-Fe3O4 has been found promising for Heck reaction of butyl acrylate, styrene or acrylonitrile with aryl halides (including Cl, Br and I). Also, Pd(0)-ABA-Fe3O4 has been found as efficient catalyst for the amination of aryl halides using aqueous ammonia. The products have been obtained in short reaction times and high yields. The catalyst was easily separated using an external magnet from the reaction mixture and reused for several runs without significant loss of its catalytic efficiency or palladium leaching. The leaching of catalyst has been examined by hot filtration and ICP-OES technique. The nanomagnetical catalyst was characterized by FTIR, TGA, XRD, VSM, TEM, SEM, EDS, DLS and ICP-OES techniques.
1,1,1-trimethylhydrazinium iodide: A novel, highly reactive reagent for aromatic amination via vicarious nucleophilic substitution of hydrogen
Pagoria, Philip F.,Mitchell, Alexander R.,Schmidt, Robert D.
, p. 2934 - 2935 (1996)
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Structural characterization and function determination of a nonspecific carboxylate esterase from the amidohydrolase superfamily with a promiscuous ability to hydrolyze methylphosphonate esters
Xiang, Dao Feng,Kumaran, Desigan,Swaminathan, Subramanyam,Raushel, Frank M.
, p. 3476 - 3485 (2014)
The uncharacterized protein Rsp3690 from Rhodobacter sphaeroides is a member of the amidohydrolase superfamily of enzymes. In this investigation the gene for Rsp3690 was expressed in Escherichia coli and purified to homogeneity, and the three-dimensional structure was determined to a resolution of 1.8 ? The protein folds as a distorted (β/α)8-barrel, and the subunits associate as a homotetramer. The active site is localized to the C-terminal end of the β-barrel and is highlighted by the formation of a binuclear metal center with two manganese ions that are bridged by Glu-175 and hydroxide. The remaining ligands to the metal center include His-32, His-34, His-207, His-236, and Asp-302. Rsp3690 was shown to catalyze the hydrolysis of a wide variety of carboxylate esters, in addition to organophosphate and organophosphonate esters. The best carboxylate ester substrates identified for Rsp3690 included 2-naphthyl acetate (kcat/Km = 1.0 × 105 M-1 s-1), 2-naphthyl propionate (k cat/Km = 1.5 × 105 M-1 s -1), 1-naphthyl acetate (kcat/Km = 7.5 × 103 M-1 s-1), 4-methylumbelliferyl acetate (kcat/Km = 2.7 × 103 M-1 s-1), 4-nitrophenyl acetate (kcat/Km = 2.3 × 105 M-1 s-1), and 4-nitrophenyl butyrate (kcat/Km = 8.8 × 105 M -1 s-1). The best organophosphonate ester substrates included ethyl 4-nitrophenyl methylphosphonate (kcat/Km = 3.8 × 105 M-1 s-1) and isobutyl 4-nitrophenyl methylphosphonate (kcat/Km = 1.1 × 104 M-1 s-1). The (SP)-enantiomer of isobutyl 4-nitrophenyl methylphosphonate was hydrolyzed 10 times faster than the less toxic (RP)-enantiomer. The high inherent catalytic activity of Rsp3690 for the hydrolysis of the toxic enantiomer of methylphosphonate esters make this enzyme an attractive target for directed evolution investigations.
Nickel catalysis for hydrogenation of p-dinitrobenzene to p-phenylenediamine
Shuvalova,Kirichenko,Kustov
, p. 34 - 38 (2017)
The activity of supported nickel catalysts (5–20% Ni) in the hydrogenation of p-dinitrobenzene to p-phenylenediamine was investigated. The catalysts were obtained by ureainduced precipitation. Activated carbon, alumina, titania, and silica gel were evaluated as supports. The most active catalysts, 5%Ni/TiO2 and 20%Ni/SiO2, provided 50–54% yields of p-phenylenediamine at complete dinitrobenzene conversion.
Photochemistry of p-Nitrophenyl Azide: Single-Electron-Transfer Reaction of the Triplet Nitrene
Liang, Tsuei-Yun,Schuster, Gary B.
, p. 546 - 548 (1986)
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One-pot aromatic amination based on carbon-nitrogen coupling reaction between aryl halides and azido compounds
Maejima, Toshihide,Shimoda, Yutaka,Nozaki, Kei,Mori, Shigeki,Sawama, Yoshinari,Monguchi, Yasunari,Sajiki, Hironao
, p. 1712 - 1722 (2012)
An efficient copper-mediated C-N coupling reaction between various aryl halides and azido compounds to produce the corresponding aromatic primary amines was established. The present amination is apparently involved in both the reduction of an azido functionality to the corresponding primary amino group and its cross-coupling reaction with aryl halides in a one-pot manner. The present amination could be applied to the synthesis of procaine, a local anesthetic drug. A mechanistic study indicated that 2-aminoethanol could work as a major hydrogen donor and the reaction would proceed without the formation of the intermediary aryl azide.
Selective nitrolytic deprotection of N-BOC-amines and N-BOC-amino acids derivatives
Strazzolini, Paolo,Melloni, Tiziana,Giumanini, Angelo G
, p. 9033 - 9043 (2001)
The extension of the deprotection procedure using HNO3 in CH2Cl2 to a number of appropriately selected N-BOC-masked amines and derivatives of natural amino acids was investigated. The method was found to work effectively with almost all tested substrates, with the exception of activated aromatic amines and heterocycles which underwent unavoidable faster oxidation. Alanine, phenylalanine, serine and lysine derivatives were efficiently deprotected, as well as dipeptide Ala-Phe, preserving the configuration of the substrates and without affecting copresent Z and ester functions, with a remarkable selectivity towards acid sensitive t-butyl esters. The obtained amino acids esters, isolated and characterized in the form of nitrates salts, proved to be suitable intermediates to be used in peptide synthesis.
Selective Reduction of Nitroarenes to Arylamines by the Cooperative Action of Methylhydrazine and a Tris(N-heterocyclic thioamidate) Cobalt(III) Complex
Ioannou, Dimitris I.,Gioftsidou, Dimitra K.,Tsina, Vasiliki E.,Kallitsakis, Michael G.,Hatzidimitriou, Antonios G.,Terzidis, Michael A.,Angaridis, Panagiotis A.,Lykakis, Ioannis N.
, p. 2895 - 2906 (2021)
We report an efficient catalytic protocol that chemoselectively reduces nitroarenes to arylamines, by using methylhydrazine as a reducing agent in combination with the easily synthesized and robust catalyst tris(N-heterocyclic thioamidate) Co(III) complex [Co(κS,N-tfmp2S)3], tfmp2S = 4-(trifluoromethyl)-pyrimidine-2-thiolate. A series of arylamines and heterocyclic amines were formed in excellent yields and chemoselectivity. High conversion yields of nitroarenes into the corresponding amines were observed by using polar protic solvents, such as MeOH and iPrOH. Among several hydrogen donors that were examined, methylhydrazine demonstrated the best performance. Preliminary mechanistic investigations, supported by UV-vis and NMR spectroscopy, cyclic voltammetry, and high-resolution mass spectrometry, suggest a cooperative action of methylhydrazine and [Co(κS,N-tfmp2S)3] via a coordination activation pathway that leads to the formation of a reduced cobalt species, responsible for the catalytic transformation. In general, the corresponding N-arylhydroxylamines were identified as the sole intermediates. Nevertheless, the corresponding nitrosoarenes can also be formed as intermediates, which, however, are rapidly transformed into the desired arylamines in the presence of methylhydrazine through a noncatalytic path. On the basis of the observed high chemoselectivity and yields, and the fast and clean reaction processes, the present catalytic system [Co(κS,N-tfmp2S)3]/MeNHNH2 shows promise for the efficient synthesis of aromatic amines that could find various industrial applications.
Electrochemical control of the catalytic activity of immobilized enzymes
Kadambar, Vasantha Krishna,Bellare, Madhura,Bollella, Paolo,Katz, Evgeny,Melman, Artem
, p. 13800 - 13803 (2020)
Regulation of the catalytic activity of enzymes immobilized on carbon nanotube electrodes was achieved by changing their local pH environment using electrochemical reactions. Reduction of oxygen increased the interfacial pH while oxidation of ascorbate decreased it, thus allowing changing rates of enzymatic reactions of electrode-immobilized amyloglucosidase and trypsin enzymes over a wide activity range.
Hydrogen-bond-regulated distinct functional-group display at the inner and outer wall of vesicles
Sikder, Amrita,Das, Anindita,Ghosh, Suhrit
, p. 6755 - 6760 (2015)
A unique supramolecular strategy enables the unidirectional assembly of two bola-shaped unsymmetric π-amphiphiles, NDI-1 and NDI-2, which feature a naphthalene-diimide chromophore connected to nonionic and anionic head groups on opposite arms. The amphiphiles differ only in the location of a hydrazide group, which is placed either on the nonionic or on the anionic arm of NDI-1 and NDI-2, respectively. The formation of hydrogen bonds between the hydrazides, which compensates for electrostatic and steric factors, promotes unidirectional alignment and the formation of monolayer vesicles. The zeta potentials and cation-assisted quantitative precipitation reveal negatively charged and nonionic outer surfaces for NDI-1 and NDI-2, respectively, indicating that hydrogen bonding also dictates the directionality of the monolayer curvature, ensuring that in both cases, the hydrazides remain at the inner wall to benefit from stronger hydrogen bonding where they are in closer proximity. This is reflected in their different abilities to inhibit α-chymotrypsin, which possesses a positively charged surface: NDI-1 induced an inhibition of 80% whereas hardly any inhibition was observed with NDI-2.
Development and Application of Efficient Ag-based Hydrogenation Catalysts Prepared from Rice Husk Waste
Unglaube, Felix,Kreyenschulte, Carsten Robert,Mejía, Esteban
, p. 2583 - 2591 (2021)
The development of strategies for the sustainable management and valorization of agricultural waste is of outmost importance. With this in mind, we report the use of rice husk (RH) as feedstock for the preparation of heterogeneous catalysts for hydrogenation reactions. The catalysts were prepared by impregnating the milled RH with a silver nitrate solution followed by carbothermal reduction. The composition and morphology of the prepared catalysts were fully assessed by IR, AAS, ICP-MS, XPS, XRD and STEM techniques. This novel bio-genic silver-based catalysts showed excellent activity and remarkable selectivity in the hydrogenation of nitro groups in both aromatic and aliphatic substrates, even in the presence of reactive functionalities like halogens, carbonyls, borate esters or nitriles. Recycling experiments showed that the catalysts can be easily recovered and reused multiple times without significant drop in performance and without requiring re-activation.
Highly efficient nitrobenzene and alkyl/aryl azide reduction in stainless steel jars without catalyst addition
Martina, Katia,Baricco, Francesca,Tagliapietra, Silvia,Moran, Maria Jesus,Cravotto, Giancarlo,Cintas, Pedro
, p. 18881 - 18888 (2018)
The mechanochemical and selective reduction of aryl nitro and aryl/alkyl azide derivatives, with either formate salts or hydrazine, to the corresponding, synthetically useful amines occurs in excellent yields in a planetary ball mill without the addition of a catalyst. This newly developed and solvent-free protocol is efficient, fast and does not require the addition of a metal hydrogenation catalyst as the stainless steel jar itself fulfils that role. The method has been applied to a broad range of compounds and excellent yields have been obtained. The formylation of alkyl amines has been successfully performed, by means of mechanochemical activation, in the presence of ammonium formate alone.
100% selective yield of m-nitroaniline by rutile TiO2 and m-phenylenediamine by P25-TiO2 during m-dinitrobenzene photoreduction
Kaur, Jaspreet,Pal, Bonamali
, p. 25 - 28 (2014)
Photoreduction of m-dinitrobenzene (25 μmol) in the deaerated aqueous iso-propanol exhibits 100% selective yield of m-nitroaniline (25 μmol) by rutile TiO2 (50 mg) or m-phenylenediamine (25 μmol) by P25-TiO2 separately under 8 and 4 h of UV light irradiation (125 W Hg arc, 10.4 mW/cm2), respectively. It revealed that insertion of a second -NO2 in nitrobenzene ring has an important role in expediting -NO2 reduction to -NH2 as compared to a negligible reduction of nitrobenzene under similar conditions, indicating that electron withdrawing groups lower the electron density on -NO2 present on meta position and favor quick reduction of the -NO2 group.
A Highly Water-Dispersible/Magnetically Separable Palladium Catalyst: Selective Transfer Hydrogenation or Direct Reductive N-Formylation of Nitroarenes in Water
Karimi, Babak,Mansouri, Fariborz,Vali, Hojatollah
, p. 1750 - 1759 (2015)
Simple ion exchange of the chloride anion of an ionic-liquid-functionalized magnetic nanoparticle with [PdCl4]2- provided a highly water-dispersible and magnetically separable palladium catalyst that exhibited excellent activity toward transfer hydrogenation reactions in water as a solvent. The catalyst demonstrated outstanding performance in aqueous-phase transfer hydrogenation of various nitroarenes in a highly chemo- and regioselective manner by using HCOONH4 as a low-cost, green, and easily available hydrogen donor. Also, by using only 0.25 mol % of the catalyst and formic acid as both a hydrogen donor and formylating agent, the catalyst showed excellent activity in the one-pot, direct synthesis of N-arylformamides from nitroarenes in water as a solvent. Notably, owing to the presence of a hydrophilic ionic liquid on the surface of silica-coated iron oxide nanoparticles, the catalyst showed highly stable dispersion in water, as evidenced by the zeta potential and extremely low affinity to the organic phase. These features make this catalyst system suitable for an efficient double-separation strategy (successive extraction/final magnetic separation). The recovered aqueous phase containing the catalyst can be simply and efficiently reused in eight runs without a decrease in activity and can be easily separated from the aqueous phase at the end of the process by applying an external magnetic field.
Revisiting ring-degenerate rearrangements of 1-substituted-4-imino-1,2,3-triazoles
Fletcher, James T.,Hanson, Matthew D.,Christensen, Joseph A.,Villa, Eric M.
, p. 2098 - 2105 (2018)
The 1-substituted-4-imino-1,2,3-triazole motif is an established component of coordination compounds and bioactive molecules, but depending on the substituent identity, it can be inherently unstable due to Dimroth rearrangements. This study examined parameters governing the ring-degenerate rearrangement reactions of 1-substituted-4-imino-1,2,3-triazoles, expanding on trends first observed by L’abbé et al. The efficiency of condensation between 4-formyltriazole and amine reactants as well as the propensity of imine products towards rearrangement was each strongly influenced by the substituent identity. It was observed that unsymmetrical condensation reactions conducted at 70 °C produced up to four imine products via a dynamic equilibrium of condensation, rearrangement and hydrolysis steps. Kinetic studies utilizing 1-(4-nitrophenyl)-1H-1,2,3-triazole-4-carbaldehyde with varying amines showed rearrangement rates sensitive to both steric and electronic factors. Such measurements were facilitated by a high throughput colorimetric assay to directly monitor the generation of a 4-nitroaniline byproduct.
Secretory leukocyte protease inhibitor: Inhibition of human immunodeficiency virus-1 infection of monocytic THP-1 cells by a newly cloned protein
Shine,Wang,Konopka,Burks,Duzgunes,Whitman
, p. 249 - 263 (2002)
The ability of the salivary protein, secretory leukocyte protease inhibitor (SLPI), to inhibit human immunodeficiency virus-1 (HIV-1) infection in vitro has been reported previously and has led to the suggestion that SLPI may be partially responsible for
A novel trypsin Kazal-type inhibitor from Aedes aegypti with thrombin coagulant inhibitory activity
Watanabe, Renata M.O.,Soares, Tatiane S.,Morais-Zani, Karen,Tanaka-Azevedo, Anita M.,Maciel, Ceres,Capurro, Margareth L.,Torquato, Ricardo J.S.,Tanaka, Aparecida S.
, p. 933 - 939 (2010)
Kazal-type inhibitors play several important roles in invertebrates, such as anticoagulant, vasodilator and antimicrobial activities. Putative Kazal-type inhibitors were described in several insect transcriptomes. In this paper we characterized for the fi
Unprecedented iron-catalyzed selective hydrogenation of activated amides to amines and alcohols
Garg, Jai Anand,Chakraborty, Subrata,Ben-David, Yehoshoa,Milstein, David
, p. 5285 - 5288 (2016)
The first example of hydrogenation of amides homogeneously catalyzed by an earth-abundant metal complex is reported. The reaction is catalyzed by iron PNP pincer complexes. A wide range of secondary and tertiary N-substituted 2,2,2-trifluoroacetamides were hydrogenated to form amines and trifluoroethanol.
Synthesis and kinetics of disassembly for silyl-containing ethoxycarbonyls using fluoride ions
Camerino, Eugene,Daniels, Grant C.,Wynne, James H.,Iezzi, Erick B.
, p. 1884 - 1888 (2018)
In this study, a series of silyl-containing ethoxycarbonates and ethoxycarbamates on electron poor anilines and phenols were synthesized and their kinetics of disassembly determined in real-time upon exposure to fluoride ion sources at room temperature. The results provide a greater understanding of stability and kinetics for silyl-containing protecting groups that eliminate volatile molecules upon removal, which will allow for simplification of orthogonal protection in complex organic molecules.
Methyltriphenylphosphonium tetrahydroborate (MePh3PBH4). A stable, selective and versatile reducing agent
Firouzabadi, Habib,Adibi, Mina
, p. 125 - 147 (1998)
Methyltriphenylphosphonium tetrahydroborate as a stable quaternary phosphonium borohydride is introduced. This compound is able to reduce aldehydes, ketones, acyl chlorides, and azides efficiently in CH2Cl2. α,β-Unsaturated carbonyl compounds are reduced selectively via 1,2-reduction. The effect of Lewis acids upon the mode and the rate of the reaction of epoxides and acetophenone are also described. This reagent is also able to bring about reductions effectively in the absence of solvent.
Amidines. III. A kinetic study of acid hydrolysis of unsymmetrical N1,N2-disubstituted amidines
Ono,Todoriki,Araya,Tamura
, p. 1158 - 1164 (1990)
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The Kinetics and Mechansim of the Hydrolysis of p-Nitrophenyl Isothiocyanate Promoted by Soft Metal Ions
Satchell, Derek P. N.,Satchell, Rosemary S.
, p. 303 - 306 (1991)
The hydrolysis of p-nitrophenyl isothiocyanate in aqueous acid solution is powerfully promoted by the Ag+ and Hg2+ ions.The organic product is p-nitroaniline.The mercury-promoted reaction is first order in isothiocyanate and in , and has ΔH(excit.) = 56 +/- 2kJ mol-1, ΔS(excit.) = -53 +/- 4 J K-1 mol-1, and kH2O/kD2O = 1.12 +/- 0.05 at 25.0 deg C.The behaviour with silver is similar: promotion is principally first order in , but in H2O there is evidence for a small kinetic term in 2. ΔH(excit.) = 59 +/- 2kJ mol-1 and ΔS(excit.) = -88 +/- 3 J K-1 mol-1 for the first-order reaction, and ΔH(excit.) = 25 +/- 5 kJ mol-1 and ΔS(excit.) = -202 +/- 12 j K-1 mol-1 for the route second order in .Use of D2O removes the second-order term, and kH2O/kD2O = 1.07 +/- 0.06 for the route involving one Ag+ ion pre-equilibrium, followed by a rate-determining attack of water to give the soft metal derivative of the corresponding thiocarbamic acid as a rapidly decomposition intermediate.
Facile and efficient amination of organic halides catalyzed by copper sulfate in PEG1000-DIL/methylcyclohexane temperature-dependent biphasic system
Hu, Yu-Lin,Wanga, Peng-Cheng,Chen, Tian,Lu, Ming
, p. 604 - 611 (2010)
A simple, efficient, and environmentally friendly procedure for the amination of organic halides catalyzed by CuSO4·5H 2O in PEG1000-DIL/methylcyclohexane temperature-dependent biphasic system is described. The product can be easily isolated by a simple decantation, and the catalytic system can be recycled and reused without loss of catalytic activity.
A palladium complex immobilized onto mesoporous silica: a highly efficient and reusable catalytic system for carbon–carbon bond formation and anilines synthesis
Nikoorazm, Mohsen,Noori, Nourolah,Tahmasbi, Bahman,Faryadi, Sara
, p. 469 - 481 (2017)
A palladium complex supported on functionalized mesoporous silica MCM-41 proved to be a highly efficient, recoverable catalyst for C–C coupling reactions and amination of aryl halides to afford anilines. The nanocatalyst was characterized by FT-IR spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis, N2 adsorption–desorption isotherms and inductively coupled plasma analysis. The catalyst could be reused for several consecutive runs without significant loss of activity. The excellent yields of products, simple reaction procedures and short reaction times are the main advantages of this methodology.
Electroreductive synthesis of polyfunctionalized pyridin-2-ones from acetoacetanilides and carbon disulfide with oxygen evolution
Gao, Shulin,Hu, Xi,Li, Weili,Li, Yanni,Liang, Deqiang,Ma, Zhongxiao,Wang, Baoling,Xu, Lichun,Zhang, Xin
supporting information, p. 1013 - 1018 (2022/02/16)
A chemical reductant or a sacrificial electron donor is required in any reduction reactions, generally resulting in undesired chemical waste. Herein, we report a reductant-free reductive [3 + 2 + 1] annulation of β-keto amides with CS2 enabled by the synergy of electro/copper/base using water as an innocuous anodic sacrifice with O2 as a sustainable by-product. This electrochemical protocol is mild and provides access to polyfunctionalized pyridin-2-ones from simple starting materials in a single step.
[1+1] Copper(II) macrocyclic Schiff base complex on rGO as a photocatalyst for reduction of nitroaromatics compounds under visible-light irradiation
Ghalebin, Saeed Nasiri,Bezaatpour, Abolfazl,Sadr, Moayad Hossaini,Sadjadi, Mirabdullah Seyed,Moghaddam, Mohammad Khodadadi,Szunerits, Sabine
, (2021/01/26)
In this work, [1 + 1] macrocyclic Copper(II) Schiff base complex ([CuL](NO3)2.H2O) was synthesized and grafted on reduced graphene oxide successfully. The novel prepared sample was characterized by physico-chemical techniques and used as a photocatalyst for the reduction of nitroaromatic compounds to their amine derivatives at room temperature under visible-light irradiation with hydrazine mono hydrate. From the prepared samples, reduced graphene oxide loaded with 30% [CuL](NO3)2.H2O catalyst (rGO/CuM30) shows the best efficiency for converting different nitroaromatic compounds to the corresponding amino compounds using visible light. As-prepared catalyst illustrated excellent activity for the reduction of 2-nitrophenol to 2-aminophenol (100% conversion) in only 90 min. Finally, the catalyst could be recovered for five times and reused without decreasing of its efficiency.