- Amine grafted Fe3O4 immobilized graphene oxide as a recyclable and effectual nanocomposite for the regioselective ring opening reaction
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This work describes the synthesis of magnetic graphene oxide (MGO), where iron oxide (Fe3O4) nanoparticles were uniformly deposited over the sheets of the graphene oxide (GO). Further, the introduction of aminopropyltrimethoxysilane (APTMS) on the surface of MGO was successfully done and results in the formation of amine-functionalized magnetic graphene oxide (MGO–NH2). The synthesized heterogeneous magnetic nanocomposite was characterized by numerous physicochemical and morphological techniques such as powder X-ray diffraction, Fourier transform infrared, thermogravimetric analysis, transmission electron microscopy, vibrating sample magnetometer, scanning electron microscopy, CHN analyzer, and energy-dispersive X-ray analysis. The synthesized nanocomposite was proved to be an effectual catalyst in the nucleophilic ring opening reactions of styrene oxide with derivatives of amines under green solvent. The present catalyst displayed good catalytic activity, short reaction time, higher regioselectivity, excellent yields and could be reutilized up to seven catalytic rounds with no substantial loss in its activity. The excellent properties of the catalyst are due to the dual character of acidic groups (existence of carboxyl groups on the sheet edges) and basic groups (amine groups anchored on the surface of GO). On completion of the reaction, the prepared nanocomposite could be effortlessly recovered from the reaction mixture by utilizing an external magnet, owing to the ferromagnetic property of Fe3O4. Graphical Abstract: [Figure not available: see fulltext.].
- Gupta, Padmini,Garkoti, Charu,Shabir, Javaid,Surabhi,Sah, Digvijay,Mozumdar, Subho
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p. 4013 - 4028
(2021/06/25)
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- A Thiophene-2-carboxamide-Functionalized Zr(IV) Organic Framework as a Prolific and Recyclable Heterogeneous Catalyst for Regioselective Ring Opening of Epoxides
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A new thiophene-2-carboxamide-functionalized Zr-UiO-66 MOF (1) was synthesized by employing a traditional solvothermal procedure. Compound 1 displayed high thermal (up to 340 °C under an Ar atmosphere) and chemical stability (in water, 1 M HCl, and acetic acid). A nitrogen physisorption measurement with the activated form of 1 (denoted 1) exhibited a BET surface area (781 m2/g) despite attachment of a bulky side chain with the linker molecule. Compound 1 was able to heterogeneously catalyze the ring-opening reaction of epoxides with amines. Catalyst 1 exhibited significant yields as well as wide substrate scope in the ring opening of epoxides by means of amines. It also displayed better catalytic performance in comparison to known MOF catalysts such as Cu3(BTC)2, Fe(BTC) (BTC: 1, 3, 5-benzenetricarboxylate), and Zr-UiO-66. Control experiments were performed with free linker, Zr(IV) salt and without catalyst 1, confirming the exclusive role of 1 in the catalytic reaction. The reusability characteristics of catalyst 1 was established for up to five consecutive catalytic cycles. The synthesis and characterization of the linker molecule, material 1, and 1 and mechanism of the catalysis reaction were studied elaborately.
- Das, Aniruddha,Anbu, Nagaraj,Reinsch, Helge,Dhakshinamoorthy, Amarajothi,Biswas, Shyam
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p. 16581 - 16591
(2019/12/04)
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- Zirconium triflate grafted on SBA-15 as a highly efficient solid acid catalyst for ring opening of epoxides by amines and alcohols
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Metal (Al, Ti, Zr) triflate grafted mesoporous SBA-15 (AlTf/S, TiTf/S, ZrTf/S) samples were synthesized as inexpensive solid acid materials by a simple one-pot-two-step synthesis methodology. These materials were characterized by X-ray diffraction, N2-sorption, thermogravimetric analysis, Fourier transform infrared spectroscopy (FT-IR), in-situ pyridine FT-IR spectroscopy, and elemental analysis. ZrTf/S was found to be a highly efficient and reusable solid acid catalyst for ring opening of epoxides with amines and alcohols and produced β-amino alcohols and β-alkoxy alcohols respectively under ambient reaction conditions. The ZrTf/S catalyst showed the highest activity, which was attributed to its high acidity compared with that of the Ti and Al containing samples.
- Tayade, Kamlesh N.,Wang, Lianyue,Shang, Sensen,Dai, Wen,Mishra, Manish,Gao, Shuang
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p. 758 - 766
(2017/04/24)
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- Greener aminolysis of epoxides on BiCl3/SiO2
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The remarkable catalytic activity of BiCl3/SiO2 for the ring-opening of epoxides with aromatic and aliphatic amines under microwave and thermal heating was observed. This eco-friendly heterogeneous catalyst displayed high to excellent regioselectivity in the synthesis of β-amino alcohols under solvent-free conditions. High turnover frequency (TOF) values under microwave heating and excellent reusability of the catalyst may significantly contribute to applied chemistry.
- Mohsenzadeh, Farshid,Aghapoor, Kioumars,Darabi, Hossein Reza,Jalali, Mohammad Reza,Halvagar, Mohammad Reza
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p. 978 - 985
(2016/08/08)
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- Manganese Complexes of Pyrrole- and Indolecarboxamide Ligands: Synthesis, Structure, Electrochemistry, and Applications in Oxidative and Lewis-Acid-Assisted Catalysis
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This work shows the synthesis and structural, spectroscopic, and electrochemical properties of MnIII complexes supported with pyrrole- and indolecarboxamide ligands. In all cases, the respective ligand constitutes a N4 coordination sphere about the MnIII ion. The MnIII complexes of pyrrolecarboxamide ligands are square pyramidal with a fifth Cl atom, whereas analogous complexes of indolecarboxamide ligands are essentially square planar. Electrochemical studies reveal highly negative MnIII/II and moderately positive MnIV/III redox potentials. In situ generated Mn4+ species of the pyrrolecarboxamide ligands were characterized by absorption and electron paramagnetic resonance spectroscopy. All complexes functioned as catalysts in olefin epoxidation reactions by using PhIO as the oxo-transfer agent. All complexes also acted as Lewis acid catalysts for ring-opening reactions of assorted epoxides with various nucleophiles. We also show a one-pot, two-step epoxidation reaction followed by ring opening, which illustrates the catalytic significance of the present complexes. Importantly, MnIII complexes carrying electron-donating substituents on the ligand were found to be better catalysts.
- Yadav, Sunil,Kumar, Sushil,Gupta, Rajeev
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p. 5534 - 5544
(2015/12/01)
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- Highly efficient and green chemical synthesis of imidazolyl alcohols and N-imidazolyl functionalized β-amino compounds using nanocrystalline ZSM-5 catalysts
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A solvent free protocol is developed for the synthesis of imidazolyl alcohols and N-imidazolyl functionalized β-amino compounds. Imidazolyl alcohols were synthesized by the ring opening of epoxides with imidazoles and N-imidazolyl functionalized β-amino compounds were synthesized by the hydroamination reaction of imidazoles and activated olefins. These reactions were catalyzed by a variety of crystalline heterogeneous catalysts such as Al/Zr substituted nanocrystalline ZSM-5 (M-Nano-ZSM-5), conventional M-ZSM-5 (where M = Zr, Al), and Zr substituted amorphous mesoporous catalysts (Zr-SBA-15 and Zr-KIT-6). Among these catalysts, nanocrystalline Zr-Nano-ZSM-5 exhibited the highest activity and regioselectivity. Structure activity relationship is explained based on the catalytic activity, acidity measurements, reactivity of reactants (imidazoles/epoxides/methyl acrylate), competitive adsorption, nature, and type of catalysts. Zr-Nano-ZSM-5 exhibited exceptionally high catalytic activity compared to the catalysts reported in the literature for the synthesis of imidazolyl alcohols and other imidazole derivatives.
- Kore, Rajkumar,Satpati, Biswarup,Srivastava, Rajendra
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- An efficient protocol for regioselective ring opening of epoxides using sulfated tungstate: Application in synthesis of active pharmaceutical ingredients atenolol, propranolol and ranolazine
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Sulfated tungstate was found to be a new and highly efficient catalyst for opening of epoxide rings by amines to give β-amino alcohols with high regioselectivity. Various advantages associated with this novel and environmental friendly protocol include solvent-free conditions, short reaction times, high product yields, simple workup procedure and easy recovery and reusability of the catalyst. This protocol has been applied for the synthesis of active pharmaceutical ingredients atenolol, propranolol and ranolazine.
- Pathare, Sagar P.,Akamanchi, Krishnacharya G.
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supporting information
p. 6455 - 6459
(2013/11/19)
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- Zinc tetrafluoroborate hydrate as a mild catalyst for epoxide ring opening with amines: Scope and limitations of metal tetrafluoroborates and applications in the synthesis of antihypertensive drugs (RS)/(R)/(S)-metoprolols
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The scope and limitations of metal tetrafluoroborates have been studied for epoxide ring-opening reaction with amines, and Zn(BF4) 2?xH2O has been found to be a mild and efficient catalyst affording high yields under solvent-free conditions at rt with excellent chemo-, regio-, and stereoselectivities. The catalytic efficiency followed the order Zn(BF4)2?xH2O ? Cu(BF4)2?xH2O > Co(BF4) 2?6H2O ? Fe(BF4)2? 6H2O > LiBF4 for reactions with cyclohexene oxide and Zn(BF4)2?xH2O ? Co(BF4) 2?6H2O ? Fe(BF4)2? 6H2O > Cu(BF4)2?xH2O for stilbene oxide, but AgBF4 was ineffective. For reaction of styrene oxide with aniline, the metal tetrafluoroborates exhibited comparable regioselectivity (1:99-7:93) with preferential reaction at the benzylic carbon of the epoxide ring. A reversal of regioselectivity (91:1-69:31) in favor of the reaction at the terminal carbon of the epoxide ring was observed for reaction with morpholine. The regioselectivity was dependent on the electronic and steric factors of the epoxide and the pKa of the amine and independent of amine nucleophilicity. The role of the metal tetrafluoroborates is envisaged as "electrophile nucleophile dual activation" through cooperativity of coordination, charge-charge interaction, and hydrogen-bond formation that rationalizes the catalytic efficiency, substrate reactivity, and regioselectivity. The methodology was used for synthesis of cardiovascular drug metoprolol as racemic and enriched enantiomeric forms.
- Pujala, Brahmam,Rana, Shivani,Chakraborti, Asit K.
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experimental part
p. 8768 - 8780
(2011/12/04)
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- Microwave-enhanced bismuth triflate-catalyzed epoxide opening with aliphatic amines
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In the presence of a catalytic amount of Bi(OTf)3·4H2O and under microwave irradiation, neat mixtures of epoxides and amines afforded smoothly the corresponding 2-amino alcohols. A wide variety of aliphatic amines were reacted with cycloalkene oxide, styrene oxide, and stilbene oxide. The reaction proceeded rapidly and afforded the 2-amino alcohols in high up to quantitative yields. All products could be obtained without aqueous work-up by simple filtration.
- Ollevier, Thierry,Nadeau, Etienne
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p. 1546 - 1550
(2008/09/19)
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- Activation and reactivity of epoxides on solid acid catalysts
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The aminolysis of epoxides over novel solid catalysts (Broensted-acidic SBA-15 functionalized with propylsulfonic acid and Lewis-acidic Ti-MCM-41) is reported. The acidic properties of these catalysts were determined by FTIR spectroscopy and temperature-programmed desorption of pyridine and NH3, respectively. The mesoporous solid acids of the present study are reusable and exhibit significantly higher catalytic activities than known catalysts for opening of the oxirane ring with nitrogen (aromatic and aliphatic amines)-containing and oxygen (alcohols)-containing nucleophiles. A range of β-amino alcohols with high regioselectivity and stereoselectivity were synthesized. Adsorption studies as well as the sigmoid shape of the conversion-versus-time plots show that the epoxide and amine compete for adsorption on the acidic sites ({single bond}SO3H or Ti4+) on the catalyst surface. Epoxide adsorption and activation on acid sites are the more critical processes. Catalytic activity decreases with increasing basicity of the amines and/or the alcohol, as well as the dielectric constant of the solvent.
- Saikia,Satyarthi,Srinivas,Ratnasamy
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p. 148 - 160
(2008/09/18)
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- N-substituted 5-aryl-1,3-oxazolidin-2-ones from arylethylene oxides
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Substituted 5-aryl-1,3-oxazolidin-2-ones can be efficiently prepared from arylethylene oxides and tert-butyl alkylcarbamates in the presence of catalytic amount of potassium tert-butoxide as a base. Their further hydrolysis under basic conditions provides aryl substituted aminoethanols in high yields.
- Wrobel,Bobin,Karczewski
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p. 907 - 912
(2007/10/03)
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- Highly chemoselective addition of amines to epoxides in water
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(Chemical Equation Presented) Aminolysis of a variety of epoxides by aliphatic and aromatic amines in water, in the absence of any catalyst with high yields, is reported. β-Amino alcohols were formed under mild conditions with high selectivity and in excellent yields.
- Azizi, Najmodin,Saidi, Mohammad R.
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p. 3649 - 3651
(2007/10/03)
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- The Reaction of Phenylglyoxal with Primary Aliphatic and Aromatic Amines. Synthesis of Phenylglyoxal Monoimines and some Derivatives.
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Condensation of phenylglyoxal with primary aliphatic amines yields the related keto-aldimines.When primary aromatic amines are used, aldimines, amino-hydroxy-ketones, diamino-ketones, and alkoxy-amino-ketones are obtained depending upon the nature of the amine and the experimental conditions.Alternatively the monoimines can be obtained by dehydration of C-hydroxyphenacylarylamines and by demethanolation of C-methoxyphenacylarylamines both on treatment with Pd/C catalyst.Reduction of phenylglyoxal monoimines with sodium borohydride yielded H-substituted 1-phenyl-2-aminoethanols and 1,3-dipolar cycloaddition of the imines with p-chlorobenzonitrile oxide afforded 4-substituted 5-benzoyl-3-(p-chlorophenyl)-4,5-dihydro-1,2,4-oxadiazoles.
- Alcaide, Benito,Escobar, Gerardo,Perez-Ossorio, Rafael,Plumet, Joaquin,Sanz, Dionisia
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p. 1466 - 1488
(2007/10/02)
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