- Synthesis of phenylthioacetomorpholide: Effect of substrate on the Willgerodt-Kindler reaction
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The effect of substrates on the Willgerodt-Kindler reaction was studied. The existence of acidic protons on these substrates accerelates the formation of thiomorpholide was found.
- Darabi, Hossein Reza,Aghapoor, Kioumars,Tabar-Heydar, Kourosh,Nooshabadi, Masoud
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Read Online
- Copper-catalyzed intermolecular oxyamination of olefins using carboxylic acids and O-benzoy I hydroxy lamines
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This paper reports a novel approach for the direct and facile synthesis of 1, 2-oxyamino moieties via an intermolecular copper-catalyzed oxyamination of olefins. This strategy utilizes O-benzoylhydroxylamines as an electrophilic amine source and carboxyli
- Hemric, Brett N.,Wang, Qiu
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Read Online
- Tb2(WO4)3@N-GQDs-FA as an efficient nanocatalyst for the efficient synthesis of β-aminoalcohols in aqueous solution
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In the current study, Tb2(WO4)3@N-(GQDs) modified with folic acid (FA) was synthesized during the chemical reaction of terbium (III) tungstate nanoparticles with nitrogen doped graphene quantum dots (N-GQDs) and introduced
- Azizi, Sajjad,Darroudi, Mahdieh,Soleymani, Jafar,Shadjou, Nasrin
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- Highly regioselective ring-opening of epoxides with amines: A metal- A nd solvent-free protocol for the synthesis of β-amino alcohols
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We herein report a metal- A nd solvent-free acetic acid-mediated ring-opening reaction of epoxides with amines. This process provides β-amino alcohols in high yields with excellent regioselectivity. Importantly, this epoxide ring-opening protocol can be used for the introduction of amines in natural products during late-stage transformations.
- Li, Dong,Wang, Jing,Yu, Shibo,Ye, Silei,Zou, Wenjie,Zhang, Hongbin,Chen, Jingbo
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supporting information
p. 2256 - 2259
(2020/03/04)
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- M-Type SrFe12O19Ferrite: An Efficient Catalyst for the Synthesis of Amino Alcohols under Solvent-Free Conditions
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Magnetically separable strontium hexaferrite SrFe12O19 was prepared using the chemical coprecipitation method, and the nanostructured material was characterized by X-ray diffraction, scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), and BET analysis. The SEM images showed the homogeneity of the chemical composition of SrFe12O19 and uniform distribution of size and morphology. The pore size of the nanomaterial and its specific area were determined by BET measurements. Strontium hexaferrite SrFe12O19 exhibited a strong magnetic field, which is highly suitable in the heterogeneous catalysis as it can be efficiently separated from the reaction. The magnetic nanocatalyst showed high activity and environmentally benign heterogeneous catalysts for the epoxide ring-opening with amines affording β-amino alcohols under solvent-free conditions. When unsymmetrical epoxides were treated in the presence of aromatics amines, the regioselectivity was influenced by the electronic and steric factors. Total regioselectivity was observed for the reactions performed with aliphatic amines. The magnetically SrFe12O19 nanocatalyst showed excellent recyclability with continuously good catalytic activities after four cycles.
- Laayati, Mouhsine,Hasnaoui, Ali,Abdallah, Nayad,Oubaassine, Saadia,Fkhar, Lahcen,Mounkachi, Omar,El Houssame, Soufiane,Ait Ali, Mustapha,El Firdoussi, Larbi
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- Ruthenium Catalyzed N-Alkylation of Cyclic Amines with Primary Alcohols
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A robust alcohol amination protocol using common saturated amines and primary alcohols as starting materials is described. The reactions are catalyzed by combination of dichloro(p-cymene)ruthenium(II) dimer precatalyst with triphenylphosphine ligand, with
- Savela, Risto,Vogt, Dieter,Leino, Reko
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p. 3030 - 3040
(2020/05/22)
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- Terbium–organic framework as heterogeneous Lewis acid catalyst for β-aminoalcohol synthesis: Efficient, reusable and green catalytic method
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A terbium–organic framework (Tb-MOF) was prepared using a previously reported procedure. Tb-MOF was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, powder X-ray diffraction and surface area analysis. Tb-MOF was e
- Karimi, Meghdad,Hajiashrafi, Taraneh,Heydari, Akbar,Azhdari Tehrani, Alireza
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- Green Regio- and Enantioselective Aminolysis Catalyzed by Graphite and Graphene Oxide under Solvent-Free Conditions
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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 %.
- Acocella, Maria Rosaria,D'Urso, Luciana,Maggio, Mario,Guerra, Gaetano
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p. 1915 - 1920
(2016/07/06)
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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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- Magnetic nano Fe3O4 catalyzed solvent-free stereo- and regioselective a-aminolysis of epoxides by amines; A green method for the synthesis of β-amino alcohols
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We report the use of magnetic nano Fe3O4 as a mild heterogeneous catalyst for the aminolysis of epoxides with amines. The approach constitutes a green method for the formation of a variety of β-amino alcohols with very high stereo- and regioselectivity under solvent-free and ambient reaction conditions. The aminolysis of chiral epoxides with amines gave the corresponding chiral β-amino alcohols with complete inversion of stereochemistry. The magnetic nano Fe3O4 catalyst can be easily recovered and recycled. Georg Thieme Verlag Stuttgart New York.
- Kumar, Amit,Parella, Ramarao,Babu, Srinivasarao Arulananda
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p. 835 - 842
(2014/04/17)
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- Versatile iridicycle catalysts for highly efficient and chemoselective transfer hydrogenation of carbonyl compounds in water
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Cyclometalated iridium complexes are shown to be highly efficient and chemoselective catalysts for the transfer hydrogenation of a wide range of carbonyl groups with formic acid in water. Examples include α-substituted ketones (α-ether, α-halo, α-hydroxy, α-amino, α-nitrile or α-ester), α-keto esters, β-keto esters and α,β-unsaturated aldehydes. The reduction was carried out at substrate/catalyst ratios of up to 50000 at pH 4.5 and required no organic solvent. The protocol provides a practical, easy and efficient way for the synthesis of β-functionalised secondary alcohols, such as β-hydroxyethers, β-hydroxyamines and β-hydroxyhalo compounds, which are valuable intermediates in pharmaceutical, fine chemical, perfume and agrochemical synthesis. Water wonder: Iridicycle catalysts are versatile and allow the highly efficient and chemoselective transfer hydrogenation of a variety of carbonyl compounds, including problematic and challenging ones, with formate in neat water (see scheme).
- Talwar, Dinesh,Wu, Xiaofeng,Saidi, Ourida,Salguero, Noemí Poyatos,Xiao, Jianliang
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supporting information
p. 12835 - 12842
(2015/03/30)
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- Efficient synthesis of β-amino alcohols by regioselective ring opening of epoxides with amines catalyzed by CuFe2O4 nanoparticles
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A simple and efficient method has been developed for the synthesis of β-amino alcohols by regioselective ring opening of epoxides with amines in the presence of CuFe2O4 nanoparticles as a heterogeneous recyclable catalyst at room temperature in high yields.
- Baghbanian, Seyed Meysam,Farhang, Maryam
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p. 1033 - 1037
(2013/09/23)
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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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- Novel Ethanediamone Hepcidine Antagonists
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The present invention relates to novel hepcidin antagonists of formula (I), pharmaceutical compositions comprising them and the use thereof as medicaments, in particular for treatment of disorders in iron metabolism, such as, in particular, iron deficiency diseases and anaemias, in particular anaemias in connection with chronic inflammatory diseases (ACD: anaemia of chronic disease and AI: anaemia of inflammation).
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- Regioselective ring-opening of aziridines and epoxides with amines under catalyst- and solvent-free condition on solid phase
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Ring opening of aziridines and epoxides with various amines afforded high regioselective products in high yields by solid phase reaction under catalyst- and solvent- free condition. The ring opening reaction proceeded rapidly by grinding.
- Li, Wanmei
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experimental part
p. 669 - 672
(2012/08/07)
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- Application of tethered ruthenium catalysts to asymmetric hydrogenation of ketones, and the selective hydrogenation of aldehydes
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An improved method for the synthesis of tethered ruthenium(II) complexes of monosulfonylated diamines is described, together with their application to the hydrogenation of ketones and aldehydes. The complexes were applied directly, in their chloride form, to asymmetric ketone hydrogenation, to give products in excess of 99% ee in the best cases, using 30 bar of hydrogen at 60 °C, and to the selective reduction of aldehydes over other functional groups. Copyright
- Jolley, Katherine E.,Prokes, Ivan,Morris, David J.,Wills, Martin,Zanotti-Gerosa, Antonio,Hancock, Fred,Dyke, Alan,Grainger, Damian M.,Medlock, Jonathan A.,Nedden, Hans G.,Le Paih, Jacques J. M.,Roseblade, Stephen J.,Seger, Andreas,Sivakumar, Vilvanathan
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supporting information
p. 2545 - 2555,11
(2012/12/12)
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- Application of tethered ruthenium catalysts to asymmetric hydrogenation of ketones, and the selective hydrogenation of aldehydes
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An improved method for the synthesis of tethered ruthenium(II) complexes of monosulfonylated diamines is described, together with their application to the hydrogenation of ketones and aldehydes. The complexes were applied directly, in their chloride form, to asymmetric ketone hydrogenation, to give products in excess of 99% ee in the best cases, using 30 bar of hydrogen at 60 °C, and to the selective reduction of aldehydes over other functional groups. Copyright
- Jolley, Katherine E.,Zanotti-Gerosa, Antonio,Hancock, Fred,Dyke, Alan,Grainger, Damian M.,Medlock, Jonathan A.,Nedden, Hans G.,Le Paih, Jacques J. M.,Roseblade, Stephen J.,Seger, Andreas,Sivakumar, Vilvanathan,Prokes, Ivan,Morris, David J.,Wills, Martin
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supporting information
p. 2545 - 2555
(2013/01/14)
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- Borrowing hydrogen methodology for amine synthesis under solvent-free microwave conditions
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Application of microwave heating to the Borrowing Hydrogen strategy to form C-N bonds from alcohols and amines is presented, removing the need for solvent and reducing the reaction times while still yielding results comparable with those using thermal heating.
- Watson, Andrew J. A.,Maxwell, Aoife C.,Williams, Jonathan M. J.
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supporting information; experimental part
p. 2328 - 2331
(2011/05/17)
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- Mg(ClO4)2, an efficient catalyst for synthesis of β-amino alcohols by ring opening of epoxides with amines under solvent-free conditions
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Commercially available magnesium perchlorate is reported as an extremely efficient catalyst for the ring-opening reaction of epoxide with various primary and secondary amines, especially diphenyl amine, under solvent-free conditions at room temperature.
- Jafari, Abbas Ali,Moradgholi
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experimental part
p. 594 - 602
(2011/04/15)
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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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- A facile and efficient synthesis of β-amino alcohols using 2,2,2-trifluoroethanol as a metal-free and reusable medium
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Trifluoroethanol was used as a reusable catalyst and medium for the ring opening of epoxides using aliphatic and aromatic amines as nucleophile under mild conditions to give the corresponding β-amino alcohols in high yields and regioselectivity.
- Khaksar, Samad,Heydari, Akbar,Tajbakhsh, Mahmood,Bijanzadeh, Hamid Reza
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experimental part
p. 106 - 110
(2010/03/03)
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- Regioselective ring-opening of epoxides with amines using Zn(ClO4)2-Al2O3 as a heterogeneous and recyclable catalyst
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A simple and efficient method has been developed for the synthesis of β-amino alcohols by regioselective ring-opening of epoxides with amines in the presence of zinc perchlorate-neutral alumina as a heterogeneous recyclable catalyst at room temperature in high yields.
- Maheswara, Muchchintala,Rao, Kummari Subba Venkata Krishna,Do, Jung Yun
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p. 1795 - 1800
(2008/09/18)
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- Highly efficient and versatile chemoselective addition of amines to epoxides in water catalyzed by erbium(III) triflate
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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.
- Procopio, Antonio,Gaspari, Marco,Nardi, Monica,Oliverio, Manuela,Rosati, Ornelio
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p. 2289 - 2293
(2008/09/18)
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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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- Zinc(II) perchlorate hexahydrate catalyzed opening of epoxide ring by amines: Applications to synthesis of (RS)/(R)-propranolols and (RS)/(R)/(S)-naftopidils
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(Figure Presented) Commercially available zinc(II) Perchlorate hexahydrate [Zn(ClO4)2·6H2O] was found to be a new and highly efficient catalyst for opening of epoxide rings by amines affording 2-amino alcohols in high yields under solvent-free conditions and with excellent chemo-, regio-, and stereoselectivities. For unsymmetrical epoxides, the regioselectivity was influenced by the electronic and steric factors associated with the epoxides and the amines. A complementarity in the regioselectivity was observed during the reaction of styrene oxide with aromatic and aliphatic amines: aromatic amines provided amino alcohols from nucleophilic attack at the benzylic carbon as major products whereas aliphatic amines resulted in formation of the amino alcohols through reaction at the terminal carbon atom of the epoxide ring as the major/sole products. Reaction of aniline with various glycidic ethers gave the amino alcohols by regioselective nucleophilic attack at the terminal carbon atom of the epoxide ring as the only/major product. Zinc(II) Perchlorate hexahydrate was found to be the best catalyst compared to other metal Perchlorates. The counteranion modulated the catalytic property of the various Zn(II) compounds that followed the order Zn(ClO4) 2·6H2O Zn(BF4)2 ~ Zn(OTf)2 ZnI2 > ZnBr2 > ZnCl2 > Zn(OAc)2 > Zn(CO3)2 in parallelism with the acidic strength of the corresponding protic acids (except for TfOH). The applicability of the methodology was demonstrated by the synthesis of cardiovascular drugs propranolol and naftopidil as racemates and optically active enantiomers.
- Shivani,Pujala, Brahmam,Chakraborti, Asit K.
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p. 3713 - 3722
(2008/02/05)
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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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- Hydrophobic amplification of noncovalent organocatalysis
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The effects of hydrogen-bonding organocatalysts and water for the acceleration of epoxide openings with a variety of nucleophiles are additive and lead to excellent yields of the catalyzed reactions in water. The Royal Society of Chemistry 2006.
- Kleiner, Christian M.,Schreiner, Peter R.
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p. 4315 - 4317
(2007/10/03)
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- BiCl3-mediated opening of epoxides, a facile route to chlorohydrins or amino alcohols: One reagent, two paths
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Opening of epoxides can be an effective means by which a variety of functional groups can be incorporated. In this letter, we outline how variation of conditions, in particular, that of solvent and concentration, give rise to different products using the Lewis acid catalyst BiCl3.
- McCluskey, Adam,Leitch, Sarah K.,Garner, James,Caden, Christine E.,Hill, Timothy A.,Odell, Luke R.,Stewart, Scott G.
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p. 8229 - 8232
(2007/10/03)
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- Copper(II) tetrafluoroborate-catalyzed ring-opening of epoxides by amines
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Copper(II) tetrafluoroborate catalyzes efficiently the selective opening of epoxides by amines leading to the synthesis of β-amino alcohols. The reaction works well with aromatic and aliphatic amines in high yields under solvent-free conditions.
- Kamal, Ahmed,Ramu,Azhar, Mohd. Ameruddin,Khanna, G.B. Ramesh
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p. 2675 - 2677
(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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- Scandium triflate as an efficient and useful catalyst for the synthesis of β-amino alcohols by regioselective ring opening of epoxides with amines under solvent-free conditions
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A simple and efficient method has been developed for the synthesis of β-amino alcohols by ring opening of epoxides in the presence of a catalytic amount of Sc(OTf)3 at room temperature under solvent-free conditions. The reaction works well with both aromatic and aliphatic amines. High regio-, and diastereoselectivity can be considered as a noteworthy advantage of this method.
- Placzek, Andrew T.,Donelson, James L.,Trivedi, Rushi,Gibbs, Richard A.,De, Surya K.
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p. 9029 - 9034
(2007/10/03)
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- Solid lithium perchlorate as a powerful catalyst for the synthesis of β-aminoalcohols under solvent-free conditions
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Lithium perchlorate catalyzed the ring opening of epoxides with amines to provide the corresponding β-aminoalcohols in excellent yields with high regioselectivity. The reaction proceeds rapidly under mild and neutral conditions and worked well with primary, secondary, aliphatic, aromatic, and hindered amines in short times at room temperature, in the absence of solvent.
- Azizi, Najmodin,Saidi, Mohammad R.
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p. 505 - 507
(2007/10/03)
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- Scope and limitations of montmorillonite K 10 catalysed opening of epoxide rings by amines
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Montmorillonite K 10 efficiently catalyses the opening of epoxide rings by amines in high yields with excellent regio- and diastereo-selectivities under solvent-free conditions at room temperature affording an improved process for synthesis of 2-amino alcohols. Reaction of cyclohexene oxide with aryl/alkyl amines leads to the formation of trans-2-aryl/alkylaminocyclohexanols. For unsymmetrical epoxides, the regioselectivity is controlled by the electronic and steric factors associated with the epoxide and the amine. Selective nucleophilic attack at the benzylic carbon of styrene oxide takes place with aromatic amines, whereas, aliphatic amines exhibit preferential nucleophilic attack at the terminal carbon. Aniline reacts selectively at the less hindered carbon of other unsymmetrical epoxides. The difference in the internal strain energy of the epoxide ring in cycloalkene oxides and alkene oxides led to selective nucleophilic opening of cyclohexene oxide by aniline in the presence of styrene oxide. Due to the chelation effect, selective activation of the epoxide ring in 3-phenoxy propylene oxide takes place in the presence of styrene oxide leading to preferential cleavage of the epoxide ring in 3-phenoxy propylene oxide by aniline.
- Chakraborti, Asit K.,Kondaskar, Atul,Rudrawar, Santosh
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p. 9085 - 9091
(2007/10/03)
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- Lithium bromide, an inexpensive and efficient catalyst for opening of epoxide rings by amines at room temperature under solvent-free condition
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Lithium bromide has been found to be an inexpensive and efficient catalyst for the opening of epoxide rings by amines, and this provides an environmentally friendly method for the synthesis of β-amino alcohols. Aromatic and aliphatic amines react with cycloalkene oxides to exclusively form trans-2-(aryl/alkylamino)cycloalkanols in high yields. A 98-100% selectivity in favour of nucleophilic attack at the benzylic carbon atom of styrene oxide is observed with aromatic amines. However, aliphatic amines exhibit a marginal preference for the reaction at the terminal carbon atom of the epoxide ring in styrene oxide. Non-styrenoidal, unsymmetrical alkene oxides undergo selective nucleophilic attack at the sterically less hindered carbon atom by aniline. The chelation effect of the Li+ ion enables selective opening of the epoxide ring in 3-phenoxypropylene oxide in the presence of styrene oxide. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Chakraborti, Asit K.,Rudrawar, Santosh,Kondaskara, Atul
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p. 3597 - 3600
(2007/10/03)
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- An efficient synthesis of 2-amino alcohols by silica gel catalysed opening of epoxide rings by amines
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Silica gel (60-120 mesh) efficiently catalyses the opening of epoxide rings by amines at rt under solvent-free conditions providing an easy method for the synthesis of 2-amino alcohols. Aromatic and aliphatic amines react with cyclohexene oxide with exclu
- Chakraborti, Asit K.,Rudrawar, Santosh,Kondaskar, Atul
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p. 1277 - 1280
(2007/10/03)
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- Synthesis and Biological activity of kappa opioid receptor agonists. Part 2: Preparation of 3-aryl-2-pyridone analogues generated by solution- and solid-phase parallel synthesis methods
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New analogues of the previously described 3-aryl pyridone KOR agonists have been synthesised by parallel synthetic methods, both in solution- and with solid-phase chemistry, making use of the well known and versatile Mitsunobu, Suzuki and Buchwald reactions. Opioid receptor binding data for the compounds produced is reported.
- Semple, Graeme,Andersson, Britt-Marie,Chhajlani, Vijay,Georgsson, Jennie,Johansson, Magnus J.,Rosenquist, Asa,Swanson, Lars
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p. 1141 - 1145
(2007/10/03)
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- ZrCl4 as a new and efficient catalyst for the opening of epoxide rings by amines
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Zirconium(IV) chloride catalyses the nucleophilic opening of epoxide rings by amines leading to the efficient synthesis of β-amino alcohols. The reaction works well with aromatic and aliphatic amines in short times at room temperature in the absence of solvent. Exclusive trans stereoselectivity is observed for cyclic epoxides. Aromatic amines exhibit excellent regioselectivity for preferential nucleophilic attack at the sterically less hindered position during the reaction with unsymmetrical epoxides. However, in case of styrene oxide, selective formation of the benzylic amine was observed during the reactions with aromatic amines.
- Chakraborti, Asit K.,Kondaskar, Atul
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p. 8315 - 8319
(2007/10/03)
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- Diisopropoxyaluminium trifluoroacetate: A new promoter for aminolysis of epoxides
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Aminolysis of symmetrical as well as unsymmetrical epoxides using various amines in the presence of diisopropoxyaluminium trifluoroacetate (DIPAT) as a new promoter gave 1,2-amino alcohols in excellent yields at room temperature with good to excellent selectivities.
- Rampalli, Sriram,Chaudhari, Sachin S.,Akamanchi, Krishnacharya G.
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- Microwave-assisted aminolysis of epoxides under solvent-free conditions catalyzed by montmorillonite clay
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The reaction of primary and secondary amines with epoxides in the presence of montmorillonite K10 clay, under solvent-free conditions and microwave irradiation affords high yields of β-amino alcohols.
- Mojtahedi, Mohammad M.,Saidi, Mohammad R.,Bolourtchian, Mohammad
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p. 128 - 129
(2007/10/03)
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- Lithium trifluoromethanesulfonate-catalysed aminolysis of oxiranes
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The aminolysis of oxiranes was found to be catalysed by lithium trifluoromethanesulfonate in acetonitrile solutions. This salt turned out to be an excellent substitute for the unsafe lithium perchlorate.
- Auge, Jacques,Leroy, Frederic
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p. 7715 - 7716
(2007/10/03)
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- Ring Opening Reactions of Epoxides Catalyzed by Samarium Iodides
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SmI2(THF)2 catalyzes the ring opening of epoxides by trimethylsilylazide, trimethylsilylcyanide and primary and secondary amines.High regioselectivities are observed in specific cases.
- Weghe, Pierre Van de,Collin, Jacqueline
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p. 1649 - 1652
(2007/10/02)
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- Boranes in Synthesis. 6. A New Synthesis of β-Amino Alcohols from Epoxides. Use of Lithium Amides and Aminoborane Catalysts To Synthesize β-Amino Alcohols from Terminal and Internal Epoxides in High Yield
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A study of the conversion of terminal and internal epoxides to the corresponding β-amino alcohols using simple primary and secondary lithium amides has been carried out.Thus, styrene oxide and 1,2-epoxydodecane react directly with primary and secondary lithium amides in THF at 25 deg C to give a single regioisomer of the corresponding β-amino alcohols in 80-100percent isolated yields.Since internal epoxides are known to yield predominantly allylic alcohols when reacted with lithium amides, we employed a series of aminoborane Lewis-acid catalists, generated in situ, to suppress formation of the allylic alcohols.Thus, the reaction of cyclohexene oxide with a variety of primary and secondary lithium amides at 34 deg C in diethyl ether in the presence of a catalytic amount of B-bromo-9-BBN afforded the corresponding β-amino alcohols in 70-95percent isolated yield.
- Harris, Clifford E.,Fisher, Gary B.,Beardsley, David,Lee, Lawrence,Goralski, Christian T.,et al.
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p. 7746 - 7751
(2007/10/02)
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- Asymmetric Synthesis. Part 6. Asymmetric Reduction of Aminoketones with (-)-Bornan-2-exo-yloxyaluminium Dichloride
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α-Dialkylaminoacetophenones and β-dialkylaminopropiophenones have been reduced asymmetrically with (-)-bornan-2-exo-yloxyaluminium dichloride to the corresponding aminoalcohols in 58-92percent enantiomeric excess.The absolute configurations of the predomi
- Samaddar, Ashis K.,Konar, Samir K.,Nasipuri, Dhanonjoy
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p. 1449 - 1451
(2007/10/02)
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