- Selective Hydrogenation of Nitriles to Primary Amines Catalyzed by a Polysilane/SiO2-Supported Palladium Catalyst under Continuous-Flow Conditions
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Hydrogenation of nitriles to primary amines with heterogeneous catalysts under liquid-phase continuous-flow conditions is described. Newly developed polysilane/SiO2-supported Pd was found to be an effective catalyst and various nitriles were converted into primary amine salts in almost quantitative yields under mild reaction conditions. Interestingly, a complex mixture was obtained under batch conditions. Lifetime experiments showed that this catalyst remained active for more than 300 h (TON≥10 000) without loss of selectivity and no metal leaching from the catalyst occurred. By using this continuous-flow hydrogenation, synthesis of venlafaxine, an antidepressant drug, has been accomplished.
- Saito, Yuki,Ishitani, Haruro,Ueno, Masaharu,Kobayashi, Shū
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p. 211 - 215
(2017/04/21)
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- Rapid Conventional and Microwave-Assisted Decarboxylation of L-Histidine and Other Amino Acids via Organocatalysis with R-Carvone under Superheated Conditions
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This article reports a new methodology taking advantage of superheated chemistry via either microwave or conventional heating for the facile decarboxylation of alpha amino acids using the recoverable organocatalyst, R-carvone. The decarboxylation of amino acids is an important synthetic route to biologically active amines, and traditional methods of amino acid decarboxylation are time consuming (taking up to several days in the case of L-histidine), are narrow in scope, and make use of toxic catalysts. Decarboxylations of amino acids including L-histidine occur in just minutes while replacing toxic catalysts with green catalyst, spearmint oil. Yields are comparable to or exceed previous methods and purification of product ammonium chloride salts is aided by an isomerization reaction of residual catalyst to phenolic carvacrol. The method has been shown to be effective for the decarboxylations of a range of natural, synthetic, and protected amino acids.
- Jackson, Douglas M.,Ashley, Robert L.,Brownfield, Callan B.,Morrison, Daniel R.,Morrison, Richard W.
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p. 2691 - 2700
(2015/12/18)
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- Hydrogenation of Aliphatic and Aromatic Nitriles Using a Defined Ruthenium PNP Pincer Catalyst
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Selective catalytic reductions of nitriles are presented using the commercially available Ru-Macho-BH complex. A variety of aliphatic, aromatic and (hetero)cyclic nitriles including industrially important adipodinitrile are hydrogenated to the corresponding primary amines. Modelling suggests the reaction follows an outer sphere hydrogenation mechanism. An efficient and selective catalytic reduction of nitriles is presented using the commercially available Ru-Macho-BH complex. A variety of aliphatic, aromatic and (hetero)cyclic nitriles including the industrially important adipodinitrile are hydrogenated to the corresponding primary amines. The reaction follows an outer-sphere mechanism.
- Neumann, Jacob,Bornschein, Christoph,Jiao, Haijun,Junge, Kathrin,Beller, Matthias
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supporting information
p. 5944 - 5948
(2015/09/22)
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- METHOD FOR DECARBOXYLATION OF AMINO ACIDS VIA IMINE FORMATION
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The present application provides methods for decarboxylation of amino acids via imine formation with a catalyst under superheated conditions in either a microwave or oil bath.
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Page/Page column 0045; 0050; 0066; 0067
(2014/09/30)
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- A practical procedure for reduction of primary, secondary and tertiary amides to amines
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A mild and general procedure for reduction of primary, secondary, and tertiary amides using catalytic triruthenium dodecacarbonyl and 1,1,3,3-tetramethyldisiloxane as reductant is described. The reaction is tolerant of numerous functional groups, and the amine products can often be isolated by direct crystallization as hydrochloride salts. The catalyst and silane are commercially available, air stable, and inexpensive, making the procedure accessible for both laboratory and large-scale applications. Copyright
- Reeves, Jonathan T.,Tan, Zhulin,Marsini, Maurice A.,Han, Zhengxu S.,Xu, Yibo,Reeves, Diana C.,Lee, Heewon,Lu, Bruce Z.,Senanayake, Chris H.
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supporting information
p. 47 - 52
(2013/03/13)
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- A study of some molecularly imprinted polymers as protic catalysts for the isomerisation of α-pinene oxide to trans-carveol
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A range of acidic Molecularly Imprinted Polymers (MIPs) were synthesised using the imprint molecule trans-carvyl amine as a transition state analogue for the selective isomerisation of α-pinene oxide to trans-carveol. The amine functionality of the imprint molecule was used to selectively position a sulfonic acid group in the MIP binding pocket utilising 4-styrene sulfonic acid as the functional monomer. Co-polymerisation with varying ratios of styrene and divinylbenzene afforded a range of MIPs which were tested for their ability to effect selective formation of trans-carveol from α-pinene oxide. Although successful imprinting was demonstrated in binding studies, it was shown that solvent effects were dominant in effecting selective formation of trans-carveol. Using DMF as solvent, up to 70% of the products from acid catalysed isomerisation of α-pinene oxide with the polystyrene MIPs were obtained via the necessary para menthyl tertiary carbocation, and industrially important trans-carveol was obtained in 45% yield.
- Motherwell, William B.,Bingham, Matilda J.,Pothier, Julien,Six, Yvan
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p. 3231 - 3241
(2007/10/03)
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- Oxidative deprotection of diphenylmethylamines
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(formula presented) The diphenylmethyl amino protecting group can be efficiently removed by initial oxidation of the amine to an imine by 2,3-dichloro-5,6-dicyanobenzoquinone. The resulting imine can then be easily hydrolyzed under mildly acidic conditions. This method is particularly well suited for the preparation of α-amino phosphinates and α-amino phosphonates.
- Sampson, Peter B.,Honek, John F.
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p. 1395 - 1397
(2008/02/09)
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- A GENERAL PROCEDURE FOR MILD AND RAPID REDUCTION OF ALIPHATIC AND AROMATIC NITRO COMPOUNDS USING AMMONIUM FORMATE AS A CATALYTIC HYDROGEN TRANSFER AGENT
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Various aliphatic and aromatic nitro compounds were selectively and rapidly reduced to their corresponding amino derivatives in very good yield using anhydrous ammonium formate as a catalytic hydrogen transfer agent.
- Ram, Siya,Ehrenkaufer, Richard E.
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p. 3415 - 3418
(2007/10/02)
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