- Ketalization of ketones to 1,3-dioxolanes and concurring self-aldolization catalyzed by an amorphous, hydrophilic SiO2-SO3H catalyst under microwave irradiation
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The amorphous, mesoporous SiO2-SO3H catalyst with a surface area of 115 m2 g-1 and 1.32 mmol H+ per g was very efficient for the protonation of ketones on a 10percent (m/m) basis, and the catalyst-bound intermediates can be trapped by polyalcohols to produce ketals in high yields or suffer aldol condensations within minutes under low-power microwave irradiation. The same catalyst can easily reverse the ketalization reaction. Printed in Brazil-
- Barbosa, Sandro L.,Ottone, Myrlene,De Almeida, Mainara T.,Lage, Guilherme L.C.,Almeida, Melina A.R.,Nelson, David Lee,Dos Santos, Wallans T.P.,Clososki, Giuliano C.,Lopes, Norberto P.,Klein, Stanlei I.,Zanatta, Lucas D.
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p. 1663 - 1671
(2018/06/29)
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- Syntheses, structures, and catalytic activities of copper(I) complexes with the ligand 2(4,5-diphenyl-1H-imidazol-2-yl)pyridine
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Two copper(I) complexes of compositions [Cu(HL)I]2·EtOH (1) and [Cu(HL)3]I·MeOH (2) were synthesized via the reactions of HL [HL = 2(4,5-diphenyl-1H-imidazol-2-yl)pyridine] and CuI in EtOH and MeOH, respectively, under solvothermal conditions. The complexes were characterized by X-ray single crystal diffraction, IR spectroscopy, and elemental analysis. Compounds 1 and 2 are catalytically active towards ketalization reaction, giving various ketals under mild conditions. Copyright
- Yang, Hua,Liu, Yonglu,Hu, Dao-Dao
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p. 394 - 397
(2014/03/21)
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- Selective acetalization of ethylene glycol with methyl 2-napthylketone over solid acids: Efficacy of acidic clay supported Cs2.5H0.5PW12O40
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Catalytic conversion of biomass to value added products is relevant with regard to several industries.Biomass derived ethylene glycol has many applications. Acetalization is used to synthesize valuablechemicals and also occasionally to protect carbonyl gr
- Yadav, Ganapati D.,Katole, Suraj O.
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p. 125 - 135
(2015/11/03)
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- Selective Acetalization of ethylene glycol with methyl 2-napthyl ketone over solid acids: Efficacy of acidic clay supported Cs2.5H0.5PW12O40
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Catalytic conversion of biomass to value added products is relevant with regard to several industries. Biomass derived ethylene glycol has many applications. Acetalization is used to synthesize valuable chemicals and also occasionally to protect carbonyl
- Yadav, Ganapati D.,Katole, Suraj O.
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p. 125 - 135
(2015/11/03)
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- Three-dimensional phosphine metal-organic frameworks assembled from Cu(I) and pyridyl diphosphine
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Metal-organic frameworks (MOFs) with phosphine based ligands are extremely attractive for catalysis. In this paper, phosphine has been successfully incorporated for the first time into three-dimensional (3D) MOFs. The MOFs are based on rigid L2M2 dimeric secondary building blocks assembled from Cu(I) and a pyridyl diphosphine ligand, 4-(3,5- bis(diphenylphosphino)phenyl)pyridine, with Br- (CuL-Br), Cl - (CuL-Br), or PF6- (CuL-PF6) as counteranions. The structures have a 4.122 net topology, which can be further simplified to 64.82-qtz. The MOFs contain 1D homochiral channels. The PF6- anions hosted in the 1D channel of CuL-PF6 can be readily exchanged with Br- or Cl- while keeping the framework intact. The materials show anion-tunable flexible porosity. CuL-Br reveals gradual uptake of MeOH, while CuL-PF6 exhibits stepwise sorption for MeOH. The heterogeneous Lewis acid catalytic activity of the MOFs has been shown in ketalization reaction. CuL-Br and CuL-PF6 are active in the reactions between ethylene glycol and 2-butanone/cyclohexanone, up to 93% yield with 0.2 mol % catalyst loading. In contrast, no reaction happens between ethylene glycol and bulky benzophenone, suggesting profound size selectivity. The catalysts can be reused with the framework left intact for three runs without loss of activity.
- Tan, Xin,Li, Lei,Zhang, Jianyong,Han, Xiaorui,Jiang, Long,Li, Fuwei,Su, Cheng-Yong
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experimental part
p. 480 - 485
(2012/06/16)
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- Reversible anion exchange and catalytic properties of two cationic metal-organic frameworks based on Cu(I) and Ag(I)
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We report the synthesis and characterization of two Ag(I)/Cu(I)-based cationic metal-organic frameworks and their application in both heterogeneous catalysis and anion exchange. The Cu(I)-based material was designed from our previously reported Ag(I) cationic topology. Both structures consist of cationic layers with π-π stacked chains of alternating metal and 4,4′-bipyridine. α,Ω-Alkanedisulfonate serves as an anionic template, electrostatically bonding to the cationic layers. Due to weak interaction between the sulfonate template and cationic extended framework, both materials display reversible anion exchange for a variety of inorganic species. Indeed, the Ag(I)-based material exhibits highly efficient uptake of permanganate and perrhenate anion trapping, a model for pertechnetate trapping. The materials also display heterogeneous Lewis acidity, likely due to the coordinatively unsaturated metal sites which only bind to two bipy nitrogens and a weak interaction with one sulfonate oxygen. A comparative study on the influence of structure versus size selectivity and reusability for both exchange and catalysis is discussed.
- Fei, Honghan,Rogow, David L.,Oliver, Scott R. J.
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experimental part
p. 7202 - 7209
(2010/07/08)
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- Intermolecular reactions of chlorohydrine anions: Acetalization of carbonyl compounds under basic conditions
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Nonenolizable aldehydes and ketones react with 2-chloroethanol and 3-chloropropanol under basic conditions (t-BuOK, DMF/THF) with formation of 2-substituted 1,3-dioxolanes and 1,3-dioxanes, respectively. Conversion of the two-step addition-alkylation process depends on the electrophilicity of the carbonyl group that governs the equilibrium of addition of chloroalkoxides. This method of protection of carbonyl groups in the form of cyclic acetals under kinetically controlled conditions is complementary to the acid-catalyzed reaction with diols.
- Barbasiewicz, Michal,Makosza, Mieczyslaw
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p. 3745 - 3748
(2007/10/03)
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- Polyaniline-Supported Sulfuric Acid Salt as a Powerful Catalyst for the Protection and Deprotection of Carbonyl Compounds
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Structurally different carbonyl compounds were converted into their corresponding cyclic acetals using polyaniline-sulfate salt as catalyst in dry toluene in excellent yield. In turn, useful deacetalization in aqueous medium was demonstrated. Chemoselective protection of carbonyl compounds was also demonstrated. The advantages of the polyaniline-sulfate salt are ease of preparation and handling, stability, reusability and activity.
- Palaniappan, Srinivasan,Narender, Puli,Saravanan, Chandrasekaran,Rao, Vaidya Jayathirtha
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p. 1793 - 1796
(2007/10/03)
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- Acetalization and Transacetalization Reactions Catalyzed by Ruthenium, Rhodium, and Iridium Complexes with {2-{{Bis[3-(trifluoromethyl)phenyl]phosphino}methyl}-2-methylpropane-1,3-diyl}bis[bis[3-(trifluoromethyl)phenyl]phosphine] (MeC[CH2P(m-CF3C6H4)2]3)
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The complexes [RhCl(3-n)(MeCN)n(CF3triphos)](CF3SO3)n (n = 1, 2; CF3triphos = MeC[CH2P(m-CF3C6H4)2]3) and [M(MeCN)3 (CF3triphos)](CF3SO3)n (M = Ru, n = 2; M = Ir, n = 3) are catalyst precursors for some typical acetalization and transacetalization reactions. The activity of these complexes is higher than those of the corresponding species containing the parent ligand MeC[CH2P(C6H5)2]3(Htriphos). Also the complexes [MCl3(tripod)] (tripod = Htriphos and CF3triphos) are active catalysts for the above reactions. The complex [RhCl2(MeCN)(CF3triphos)](CF3SO3) catalyzes the acetalization of benzophenone.
- Suelue, Mustafa,Venanzi, Luigi M.
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p. 898 - 907
(2007/10/03)
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- Highly efficient heterogeneous acetalization of carbonyl compounds catalyzed by a titanium cation-exchanged montmorillonite
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The titanium cation-exchanged montmorillonite efficiently catalyzed the selective acetalization of various carbonyl compounds as a recyclable solid acid. This heterogeneous catalyst has an advantage of a strikingly simple workup procedure over conventional homogeneous acids.
- Kawabata, Tomonori,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
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p. 8329 - 8332
(2007/10/03)
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- Solvent free protection of carbonyl group under microwave irradiation
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Protection of aldehydes and ketones as acetals or dioxolanes catalysed by PTSA or KSF clay was readily achieved from orthoformates, 1,2-ethanediol or 2,2-dimethyl-1,3-dioxolane without solvent under microwave irradiation.
- Perio, Bertrand,Dozias, Marie-Joelle,Jacquault, Patrick,Hamelin, Jack
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p. 7867 - 7870
(2007/10/03)
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- N-(arylmethyl)-2-(or -4)-cyanopyridinium hexafluoroantimonates as new useful catalysts for acetalization of carbonyl compounds
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Carbonyl compounds 1 were converted to the corresponding 1,3-dioxolanes 2 and 1,3-dioxanes 4 with ethylene glycol and 2,2-dimethyl-1,3-propandiol, respectively, in the presence of 1-3 mol% of N-(benzyl, 4-methylbenzyl or 4-methoxybenzyl)-2(or -4)cyanopyridinium hexafluoroantimonates 3. The catalyst 3d was also effective for the tetrahydropyranylation.
- Lee,Lee,Takata,Endo
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p. 368 - 370
(2007/10/02)
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- FACILE SYNTHETIC METHODS OF ACETALS AND CROWN ETHERS FROM THE REACTION OF DIPHENYLDIAZOMETHANE WITH 2,3-DICHLORO-5,6-DICYANOBENZOQUINONE IN THE PRESENCE OF ALCOHOLS
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The reaction of diphenyldiazomethane with 2,3-dichloro-5,6-dicyanobenzoquinone in the presence of alcohols and thiols gave the corresponding benzophenone acetals and thioacetals at 20-25 deg C in 1,2-dichloroethane.The mechanism of the reaction will be discussed.
- Oshima, Takumi,Nishioka, Ryoji,Nagai, Toshikazu
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p. 3919 - 3922
(2007/10/02)
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