- Novel applications of functionalized 2,1,3-benzothiadiazoles for coordination chemistry and crystal engineering
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Two novel applications of functionalized 2,1,3-benzothiadiazoles for metal coordination chemistry and crystal engineering of organic solids are presented. 4-Amino-2,1,3-benzothiadiazole (1) forms a 2:1 complex with ZnCl2 (complex 2) and a 1:1 complex with 4-nitro-2,1,3-benzothiadiazole (3) (complex 4). The structures of compounds 1-4 were confirmed by single-crystal X-ray diffraction and studied by UV-Vis and IR spectroscopy, and DFT and QTAIM calculations. Complex 2 is the first structurally defined Zn complex with 2,1,3-benzothiadiazole ligands. In this complex, both molecules 1 are coordinated to Zn only by amino groups, thus revealing a novel type of coordination of this ligand to the metal center. According to 1H NMR data, complex 2 dissociates in CHCl3, THF or DMSO solutions. There are only a few examples of similar complexes, which are also considered to dissociate in solutions. In crystalline complex 4, molecules 1 and 3 form infinite alternating π-stacks connected by lateral S...N interactions between the neighboring stacks. Intermolecular S...N interactions are also observed in the crystals of individual 1 and 3 but the packing motifs are different from those in 4. DFT calculations predict a small charge transfer (CT, ~0.02e at B97-D3 level) from 1 to 3 upon the formation of 4, which therefore is an unprecedented CT complex where both donor and acceptor moieties are the derivatives of the 2,1,3-benzothiadiazole ring system. This finding creates some new prospects for the crystal engineering of organic solids. Crystalline complex 4 is characterized by an intense CT absorption band with a maximum at ~550 nm. However, according to DFT and QTAIM calculations the complex is weakly bonded and its formation is not observed in CH 2Cl2 solution with 1H NMR and UV-Vis techniques.
- Bashirov, Denis A.,Sukhikh, Taisiya S.,Kuratieva, Natalia V.,Chulanova, Elena A.,Yushina, Irina V.,Gritsan, Nina P.,Konchenko, Sergey N.,Zibarev, Andrey V.
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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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- Heterogeneous Iron-Catalyzed Hydrogenation of Nitroarenes under Water-Gas Shift Reaction Conditions
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Reduction of various nitroarenes in the presence of heterogeneous iron oxide-based catalyst Fe 2 O 3 /NGr@C under water-gas shift reaction (WGSR) conditions has been demonstrated. The catalytic material is prepared in a straightforward manner via deposition/pyrolysis of iron-phenanthroline complex on carbon support. It shows high chemoselectivity towards the reduction of nitroarenes in the presence of other reducible and/or poisoning-capable functional groups. Hydrogenation is achieved using CO/H 2 O as a hydrogen source. Furthermore, it is demonstrated that the presence of triethylamine additive has a significant positive effect on the rate of reduction.
- Ryabchuk, Pavel,Junge, Kathrin,Beller, Matthias
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supporting information
p. 4369 - 4376
(2018/11/21)
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- Supported Rhodium Nanoparticles Catalyzed Reduction of Nitroarenes, Arylcarbonyls and Aryl/Benzyl Sulfoxides using Ethanol/Methanol as In Situ Hydrogen Source
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A facile reduction reaction of nitroarenes, aryl carbonyls and aryl/benzyl sulfoxides was performed under polystyrene supported rhodium (Rh@PS) catalyzed conditions using ethanol/methanol as in situ hydrogen source. The catalyst Rh@PS played a pivotal role in the oxidation of ethanol/methanol in the presence of traces of aerial oxygen and base to produce hydrogen gas, enough for further reduction reaction. Transmission electron microscopy (TEM) analysis indicated that the average particle size of the Rh nanoparticles (NPs) lies between 2–3 nm; this is responsible for its high catalytic activity. The advantages of Rh@PS are its catalytic activity, easy preparation, recovery, recyclability for several runs, and low metal leaching during reaction. (Figure presented.).
- Sharma, Saurabh,Bhattacherjee, Dhananjay,Das, Pralay
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supporting information
p. 2131 - 2137
(2018/04/17)
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- Chemoselective Hydrogenation of Nitroarenes Catalyzed by Molybdenum Sulphide Clusters
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Herein, we describe an atom efficient and general protocol for the chemoselective hydrogenation of nitroarenes to anilines catalyzed by well-defined diimino and diamino cubane-type Mo3S4 clusters. The novel diimino [Mo3S4Cl3(dnbpy)3]+ ([5]+) (dnbpy=4,4′-dinonyl-2,2′-dipyridyl, L1) trinuclear complex was synthesized in high yields by simple ligand substitution reactions starting from the thiourea (tu) [Mo3S4(tu)8(H2O)]Cl4?4 H2O (3) precursor. This strategy has also been successfully adapted for the isolation of the diamino [Mo3S4Cl3(dmen)3](BF4) ([6](BF4)), (dmen=N,N′-dimethylethylenediamine) salt. Applying these catalysts, high selectivity in the hydrogenation of functionalized nitroarenes has been accomplished. Over thirty anilines bearing synthetically functional groups have been synthesized in 70 to 99 % yield. Notably, the integrity of the cluster core is preserved during catalysis. Based on kinetic studies on the hydrogenation of nitrobenzene and other potential reaction intermediates, the direct reduction to aniline is the preferential route.
- Pedrajas, Elena,Sorribes, Iván,Gushchin, Artem L.,Laricheva, Yuliya A.,Junge, Kathrin,Beller, Matthias,Llusar, Rosa
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p. 1128 - 1134
(2017/03/27)
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- Co-based heterogeneous catalysts from well-defined Α-diimine complexes: Discussing the role of nitrogen
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Ar-BIANs and related α-diimine Co complexes were wet impregnated onto Vulcan XC 72 R carbon black powder and used as precursors for the synthesis of heterogeneous supported nanoscale catalysts by pyrolysis under argon at 800?°C. The catalytic materials feature a core-shell structure composed of metallic Co and Co oxides decorated with nitrogen-doped graphitic layers (NGr). These catalysts display high activity in the liquid phase hydrogenation of aromatic nitro compounds (110?°C, 50 bar H2) to give chemoselectively substituted aryl amines. The catalytic activity is closely related to the amount and type of nitrogen atoms in the final catalytic material, which suggests a heterolytic activation of dihydrogen.
- Formenti, Dario,Ferretti, Francesco,Topf, Christoph,Surkus, Annette-Enrica,Pohl, Marga-Martina,Radnik, J?rg,Schneider, Matthias,Junge, Kathrin,Beller, Matthias,Ragaini, Fabio
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- A highly sensitive fluorescent probe for detection of hydrazine in gas and solution phases based on the Gabriel mechanism and its bioimaging
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A new probe 2-benzo[1,2,5]thiadiazol-4-yl-isoindole-1,3-dione (BTI) based on the Gabriel reaction mechanism was synthesized and characterized for the specific detection of hydrazine with high selectivity against other amines in an organo-aqueous solution. Upon hydrazinolysis of BTI in the presence of hydrazine in a H2O-DMSO (4:6, v/v) solution (10 mM HEPES buffer, pH 7.4) at room temperature, the chemosensor produces fluorescent aminobenzthiadiazole with a maximum emission at 498 nm along with a color change from colorless to green, allowing selective colorimetric and fluorometric detection of hydrazine by the naked eye. Probe BTI was also successfully applied in vapor phase hydrazine detection into a solid state over other interfering volatile analytes. Furthermore, the probe BTI coated with silica gel TLC plates could act as a visual and fluorimetric probe for hydrazine vapor detection. The experimental detection limit of hydrazine is 2.9 ppb, which is well below the accepted limit (10 ppb) for hydrazine set by the U.S. Environmental Protection Agency (EPA). DFT and TDDFT calculations were performed in order to demonstrate the sensing mechanism and the electronic properties of probe and hydrazinolysis products. Additionally, probe BTI could also be applied for the imaging of hydrazine in living cells.
- Maji, Rajkishor,Mahapatra, Ajit Kumar,Maiti, Kalipada,Mondal, Sanchita,Ali, Syed Samim,Sahoo, Prithidipa,Mandal, Sukhendu,Uddin, Md Raihan,Goswami, Shyamaprosad,Quah, Ching Kheng,Fun, Hoong-Kun
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p. 70855 - 70862
(2016/08/05)
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- Nitrogen-doped graphene-activated iron-oxide-based nanocatalysts for selective transfer hydrogenation of nitroarenes
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Nanoscaled iron oxides on carbon were modified with nitrogen-doped graphene (NGr) and found to be excellent catalysts for the chemoselective transfer hydrogenation of nitroarenes to anilines. Under standard reaction conditions, a variety of functionalized and structurally diverse anilines, which serve as key building blocks and central intermediates for fine and bulk chemicals, were synthesized in good to excellent yields.
- Jagadeesh, Rajenahally V.,Natte, Kishore,Junge, Henrik,Beller, Matthias
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p. 1526 - 1529
(2015/03/14)
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- Highly selective transfer hydrogenation of functionalised nitroarenes using cobalt-based nanocatalysts
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Anilines are important feedstock for the synthesis of a variety of chemicals such as dyes, pigments, pharmaceuticals and agrochemicals. The chemoselective catalytic reduction of nitro compounds represents the most important and prevalent process for the manufacture of functionalized anilines. Consequently, the development of selective catalysts for the reduction of nitro compounds in the presence of other reducible groups is a major challenge and is crucial. In this regard, herein we show that the cobalt oxide (Co3O4-NGr@C) based nano-materials, prepared by the pyrolysis of cobalt-phenanthroline complexes on carbon constitute highly selective catalysts for the transfer hydrogenation of nitroarenes to anilines using formic acid as a hydrogen source. Applying these catalysts, a series of structurally diverse and functionalized nitroarenes have been reduced to anilines with unprecedented chemo-selectivity tolerating halides, olefins, aldehyde, ketone, ester, amide and nitrile functionalities.
- Jagadeesh, Rajenahally V.,Banerjee, Debasis,Arockiam, Percia Beatrice,Junge, Henrik,Junge, Kathrin,Pohl, Marga-Martina,Radnik, J?rg,Brückner, Angelika,Beller, Matthias
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supporting information
p. 898 - 902
(2015/03/04)
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- Iron and palladium(II) phthalocyanines as recyclable catalysts for reduction of nitroarenes
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Iron(II) and palladium(II) phthalocyanines have been established as recyclable heterogeneous catalysts for the reduction of aromatic nitro compounds to corresponding amines using diphenylsilane/sodium borohydride as hydrogen sources in ethanol. Various reducible functional groups, such as acetyl, ester, cyano, amide, sulphonamide and carboxylic acid etc. were well tolerated, and the methods were applicable up to gram scale. Mechanistic studies showed that reduction of nitro group proceed through direct (nitroso) pathway and possibly iron or palladium phthalocyanines activates nitro group for reduction. FePc and PdPc also catalyzed the generation of hydrogen from the combination of diphenylsilane/sodium borohydride and ethanol.
- Verma, Praveen Kumar,Bala, Manju,Thakur, Kavita,Sharma, Upendra,Kumar, Neeraj,Singh, Bikram
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p. 1258 - 1267
(2014/07/21)
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- Nanoscale Fe2O3-based catalysts for selective hydrogenation of nitroarenes to anilines
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Production of anilines - key intermediates for the fine chemical, agrochemical, and pharmaceutical industries - relies on precious metal catalysts that selectively hydrogenate aryl nitro groups in the presence of other easily reducible functionalities. Herein, we report convenient and stable iron oxide (Fe2O3) - based catalysts as a more earth-abundant alternative for this transformation. Pyrolysis of iron-phenanthroline complexes on carbon furnishes a unique structure in which the active Fe2O 3 particles are surrounded by a nitrogen-doped carbon layer. Highly selective hydrogenation of numerous structurally diverse nitroarenes (more than 80 examples) proceeded in good to excellent yield under industrially viable conditions.
- Jagadeesh, Rajenahally V.,Surkus, Annette-Enrica,Junge, Henrik,Pohl, Marga-Martina,Radnik, Joerg,Rabeah, Jabor,Huan, Heming,Schunemann, Volker,Brueckner, Angelika,Beller, Matthias
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p. 1073 - 1076
(2014/01/06)
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- Phosphane-free green protocol for selective nitro reduction with an iron-based catalyst
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Iron phthalocyanine with iron sulfate has been successfully applied for high chemo- and regioselective reduction of aromatic nitro compounds to give the corresponding amines in a green solvent system without using any toxic ligand. The catalytic systems were also compatible with a large range of other reducible functional groups, such as keto, acid, amide, ester, halogen, lactone, nitrile, N-benzyl, O-benzyl, hydroxy, and heterocycles. In the present study, dinitro compounds have been regioselectively reduced to the corresponding amines with high yield. In most of the cases the conversion and selectivity was greater than 99% as determined by GC-MS analysis. Copyright
- Sharma, Upendra,Verma, Praveen Kumar,Kumar, Neeraj,Kumar, Vishal,Bala, Manju,Singh, Bikram
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experimental part
p. 5903 - 5907
(2011/06/20)
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- Highly chemo- and regioselective reduction of aromatic nitro compounds catalyzed by recyclable copper(II) as well as cobalt(II) phthalocyanines
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Copper/cobalt phthalocyanines were established for the first time as catalysts for the very efficient chemo- and regioselective reduction of aromatic nitro compounds to generate the corresponding amines. The selective reduction of nitro compounds was observed in the presence of a large range of functional groups such as aldehyde, keto, acid, amide, ester, halogen, lactone, nitrile and heterocyclic functional groups. Furthermore, the present method was found to be highly regioselective towards the reduction of aromatic dinitro compounds in a short time with high yields. In most of the cases the conversion and selectivity were >99% as monitored by GC-MS. The reduction mechanism was elucidated by UV-vis and electrospray ionization quadrupole time-of-flight tandem mass spectrometry.
- Sharma, Upendra,Kumar, Praveen,Kumar, Neeraj,Kumar, Vishal,Singh, Bikram
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experimental part
p. 1834 - 1840
(2010/10/21)
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- A practical and chemoselective reduction of nitroarenes to anilines using activated iron
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Reduction of nitroarenes to anilines using activated iron generated by Fe/HCl or Zn/FeSO4 is described. A variety of functional groups such as alkyne, ketone, enone, nitrile, lactone, and aromatic halide are well tolerated under these conditions.
- Liu, Yugang,Lu, Yansong,Prashad, Mahavir,Repic, Oljan,Blacklock, Thomas J.
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p. 217 - 219
(2007/10/03)
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- N-(INDOLETHYL-)CACLOAMINE COMPOUNDS
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The invention relates to n-(indolethyl-)cacloamine compounds of a formula (i), wherein R1, R1 x, Ar and n have a meaning of the claim 1. The inventive compounds consist of inhibitors of serotonin recapture (SSRI) and activators of serotoninenergic receptors 5-HT1A and 5-HT2A. Said compounds are used for preventing and treating various diseases of the central nervous system such as depression, dyskenesia, Parkinson's disease, dementia, vascular cerebral accident, schizophrenia, Alzheimer disease, Lewy bodies dementia, Huntington disease, Gille de la Tourette syndrome, anxiety, learning difficulties, memory disorder, pain, insomnia and neurodegenerative diseases.
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Page/Page column 23-24
(2008/06/13)
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- Pharmaceutically active pyrrolidine derivatives
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The present invention is related to pyrrolidine derivatives of formula (I). Said compounds are preferably for use as pharmaceutically active compounds. Specifically, pyrrolidine derivatives of formula (I) are useful in the treatment and/or prevention of premature labor, premature birth and dysmenorrhea. In particular, the present invention is related to pyrrolidine derivatives displaying a substantial modulatory, notably an antagonist activity of the oxytocin receptor. More preferably, said compounds are useful in the treatment and/or prevention of disease states mediated by oxytocin, including premature labor, premature birth and dysmenorrhea. The present invention is furthermore related to novel pyrrolidine derivatives as well as to methods of their preparation, wherein X is selected from the group consisting of CR6R7, NOR6, NNR6R7; A is selected from the group consisting of —(C═O)—, —(C═O)—O—, —C(═NH)—, —(C═O)—NH—, —(C═S)—NH, —SO22—, —SO2NH—, —CH2—,B is either a group —(C═O)—NR8R9 or represents a heterocyclic residue having the formula (a) wherein Q is NR10, O or S; n is an integer selected of 0, 1 or 2; Y, Z and E form together with the 2 carbons to which they are attached a 5-6 membered aryl or heteroaryl ring.
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- Pharmaceutically active pyrrolidine derivatives as bax inhibitors
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The present invention is related to new substituted pyrrolidine derivatives of formula (I). Said compounds are preferably for use as pharmaceutically active compounds. Specifically, pyrrolidine derivatives of formula (I) are useful in the treatment and/or prevention of neurodegenerative disorders, diseases associated with polygultamine tracts, epilepsy, ischemia, infertility, cardiovascular disorders renal hypoxia, hepatitis and AIDS. Said pyrrolidine derivatives display a modulatory and most notably a down-regulating-up to an inhibitory-activity with respect to the cellular death agonist Bax and/or the activation pathways leading to Bax and allows therefore to block the release of cytochrome (c). The present invention is furthermore related to novel pharmaceutically activity substituted pyrrolidine derivatives as well as to methods of their preparation, wherein X is selected from the group consisting of O, S, CRR, NOR, NNRR; A is selected from the group consisting of —(C═O)—, —(C═O)—O—, —C(═NH)—, —(C═O)—NH—, —(C═S)—NH, —SO2-, —SO2NH—; —CH2-; B is either a group —(C═O)—NRR or represents a heterocyclic residue having the formula (II) wherein Q is NR, O or S; n is an integer selected of 0, 1 or 2; Y, Z and E form together with the 2 carbons to which they are attached a 5-6 membered aryl or heteroaryl ring.
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- Conversion of 4-Substituted Benzo-2,1,3-thiadiazoles to 5-Chloro-4,7-dioxobenzo-2,1,3-thiadiazole by Action of Hydrogen Peroxide and Hydrochloric Acid
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Under the influence of hydrogen peroxide and hydrochloric acid in acetonitrile 4-substituted benzo-2,1,3-thiadiazoles form 5-chloro-4,7-dioxobenzo-2,1,3-thiadiazole. 4-Alkoxy- and 4-benzo-2,1,3-thiadiazole gives, in additition, the corresponding 5,7-dichloro derivatives.
- Belen'kaya, I. A.,Krokhina, G. P.,Sirik, S. A.,Andronati, S. A.
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