20245-72-1Relevant articles and documents
Light-enhanced acid catalysis over a metal-organic framework
Xu, Caiyun,Sun, Keju,Zhou, Yu-Xiao,Ma, Xiao,Jiang, Hai-Long
supporting information, p. 2498 - 2501 (2018/03/21)
A Br?nsted acid-functionalized metal-organic framework (MOF), MIL-101-SO3H, was prepared for acid-engaged esterification reactions. Strikingly, for the first time, the MOF exhibits significantly light-enhanced activity and possesses excellent activity and recyclability, with even higher activity than H2SO4 under light irradiation.
An efficient method for regioselective ring opening of epoxides by amines under microwave irradiation using Bi(NO3)3·5H2O as a catalyst
Bansal, Shobha,Kumar, Yogendra,Pippal, Parveen,Das, Dipak K.,Pramanik, Panchanan,Singh, Prabal P.
, p. 2668 - 2671 (2017/04/03)
Bismuth(iii)nitrate pentahydrate, a highly efficient environmentally benign catalyst, is used for the nucleophilic ring opening of epichlorohydrin and styrene oxide with aromatic, aliphatic and heteroaromatic amines under solvent free microwave conditions
Green Regio- and Enantioselective Aminolysis Catalyzed by Graphite and Graphene Oxide under Solvent-Free Conditions
Acocella, Maria Rosaria,D'Urso, Luciana,Maggio, Mario,Guerra, Gaetano
, p. 1915 - 1920 (2016/07/06)
The ring-opening reactions of epoxides with amines were efficiently and regioselectively catalyzed by high-surface-area graphite and graphene oxide under metal-free and solvent-free conditions. For epoxides without aryl groups, catalytic activity was observed only for graphene oxide, and hence, the activity must have been due to its acidic groups. For styrene oxide, instead, graphite and graphene oxide exhibited rather similar catalytic activities, and hence, the activity was mainly due to activation of the electrophilic epoxide by π-stacking interactions with the graphitic π system. The described aminolysis procedure is green and cheap because the catalyst can be recovered and recycled without loss of efficiency. Moreover, these heterogeneous catalysts exert high stereoselective control in the presence of nonracemic epoxides and provide chiral β-amino alcohols with enantiomeric excess values up to 99 %.
Manganese Complexes of Pyrrole- and Indolecarboxamide Ligands: Synthesis, Structure, Electrochemistry, and Applications in Oxidative and Lewis-Acid-Assisted Catalysis
Yadav, Sunil,Kumar, Sushil,Gupta, Rajeev
, p. 5534 - 5544 (2015/12/01)
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.
Quaternary ammoniums and a cationic sodium complex as supramolecular catalysts in ring-opening of epoxides by amines
Thomas, Coralie,Brut, Sébastien,Bibal, Brigitte
, p. 1646 - 1650 (2014/02/14)
Supramolecular ionic organocatalysts and a metal-based catalyst were investigated in the ring-opening of epoxides by amines, without any artifice to enhance conversion (i.e., solvophobic effect, extended reaction time, heating, excess of amine, high catalyst loading). Different β-amino-alcohols were obtained in satisfying conversion (50-80%) in 24 h, under mild conditions.
Three-dimensional {Co3+-Zn2+} and {Co 3+-Cd2+} networks originated from carboxylate-rich building blocks: Syntheses, structures, and heterogeneous catalysis
Kumar, Girijesh,Gupta, Rajeev
, p. 10773 - 10787 (2013/10/22)
The present work shows the utilization of Co3+ complexes appended with either para- or meta-arylcarboxylic acid groups as the molecular building blocks for the construction of three-dimensional {Co 3+-Zn2+} and {Co3+-Cd2+} heterobimetallic networks. The structural characterizations of these networks show several interesting features including well-defined pores and channels. These networks function as heterogeneous and reusable catalysts for the regio- and stereoselective ring-opening reactions of various epoxides and size-selective cyanation reactions of assorted aldehydes.
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
Pujala, Brahmam,Rana, Shivani,Chakraborti, Asit K.
experimental part, p. 8768 - 8780 (2011/12/04)
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.
Thiourea catalyzed aminolysis of epoxides under solvent free conditions. Electronic control of regioselective ring opening
Chimni, Swapandeep Singh,Bala, Neeraj,Dixit, Vaibhav A.,Bharatam, Prasad V.
experimental part, p. 3042 - 3049 (2010/06/14)
A reactant economizing process for the regioselective aminolysis of epoxides using equimolar quantities of reactants catalyzed by the double hydrogen bond donor N,N′-bis[3,5-bis(trifluoromethyl)phenyl]thiourea is reported. Regioselectivity of the reaction
CARBONYLAMINO PYRROLOPYRAZOLES, POTENT KINASE INHIBITORS
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Page/Page column 61-62, (2009/12/28)
Carbonylamino Pyrrolopyrazole compounds of formula I, compositions including these compounds and methods of their use are provided. Preferred compounds of formula I have activity as protein kinase inhibitors, including as inhibitors of PAK4.
Highly efficient and versatile chemoselective addition of amines to epoxides in water catalyzed by erbium(III) triflate
Procopio, Antonio,Gaspari, Marco,Nardi, Monica,Oliverio, Manuela,Rosati, Ornelio
, p. 2289 - 2293 (2008/09/18)
Er(OTf)3 is proposed as a highly efficient and reusable catalyst for the opening of epoxides in water with aliphatic as well as aromatic amines leading to the synthesis of β-amino alcohols. The aqueous conditions employed in the present method will make it 'environmentally friendly' and potentially useful for industrial applications.
