- Deactivation mechanisms of iodo-iridium catalysts in chiral amine racemization
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The homogenous, [IrCp?I2]2, SCRAM catalyst (1) is active in the racemization of chiral amines. NMR, kinetic and structural mechanistic studies have determined the cause of catalyst deactivation to occur when ammonia or methylamine are liberated by hydrolysis or aminolysis of the intermediate imine, which tightly coordinate to the iridium centre to block turnover. Control of moisture and substrate concentration can suppress deactivation, whilst partial reactivation of spent catalyst was identified using hydroiodic acid.
- Kwan, Maria H.T.,Pokar, Nisha P.B.,Good, Catherine,Jones, Martin F.,Munday, Rachel,Screen, Thomas,Blacker, A. John
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- Catalytic Asymmetric Umpolung Allylation of Imines
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Here we report an iridium-catalyzed asymmetric umpolung allylation of imines as a general approach to prepare 1,4-disubstituted homoallylic amines, a fundamental class of compounds that are hitherto not straightforward to obtain. This transformation proceeds by a cascade involving an intermolecular regioselective allylation of 2-azaallyl anions and a following 2-aza-Cope rearrangement, utilizes easily available reagents and catalysts, tolerates a substantial scope of substrates, and readily leads to various enantioenriched, 1,4-disubstituted homoallylic primary amines.
- Liu, Jie,Cao, Chao-Guo,Sun, Hong-Bao,Zhang, Xia,Niu, Dawen
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supporting information
p. 13103 - 13106
(2016/10/22)
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- RACEMISATION PROCESS FOR OBTAINING (1S,4S) N-METHYL-4-(3,4-DICHLOROPHENYL)-1,2,3,4-TETRAHYDRO-1-NAPHTHALENEAMINE (SERTRALINE)
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The present invention relates to a novel process for obtaining (1S,4S) N-methyl-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-1-naphthaleneamine from a mixture of its isomers. The process involves isomerising the 1-position and the 4-position and effecting se
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Page/Page column 13-14
(2009/04/25)
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- A low-waste process to sertraline by diastereomeric crystal resolution and waste isomer racemisation
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A semi-continuous method for recovering waste sertraline isomers from a diastereomeric crystallisation process is described in which the mother liquors from a highly selective mandelic acid resolution for the (1S,4S) isomer are treated sequentially with S
- Blacker, A. John,Brown, Stuart,Clique, Blandine,Gourlay, Brian,Headley, Catherine E.,Ingham, Stephen,Ritson, Dougal,Screen, Thomas,Stirling, Matthew J.,Taylor, David,Thompson, Gary
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experimental part
p. 1370 - 1378
(2010/04/26)
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- Racemisation process
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The present invention relates to a novel process for obtaining (1S,4S)N-methyl-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-1-naphthaleneamine from a mixture of its isomers. The process involves isomerising the 1-position and the 4-position and effecting separation of the desired isomer by methods such as fractured crystallization. The process can be operated as a continuous process.
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Page/Page column 13
(2008/12/07)
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- Asymmetric reduction of substituted indanones and tetralones catalyzed by chiral dendrimer and its application to the synthesis of (+)-sertraline
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A recoverable dendrimeric supported prolinol was used as a catalyst in the asymmetric reduction of indanones and tetralones to give separable cis and trans isomers up to 97% ee. This method was also applied in the enantioselective synthesis of the antidepressant drug (+)-sertraline.
- Wang, Guangyin,Zheng, Changwu,Zhao, Gang
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p. 2074 - 2081
(2007/10/03)
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- CATALYST COMPOSITIONS AND THEIR USE IN THE DE-ENRICHMENT OF ENANTIOMERICALLY ENRICHED SUBSTRATES
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There is provided a process for the de-enrichment of enantiomerically enriched compositions which comprises reacting an enantiomerically enriched composition comprising at least a first enantiomer or diastereomer of a substrate comprising a carbon-heteroatom bond, wherein the carbon is a chiral centre and the heteroatom is a group V heteroatom, in the presence of a catalyst system and optionally a reaction promoter to give a product composition comprising first and second enantiomers or diastereomers of the substrate having a carbon-heteroatom bond, the ratio of second to first enantiomer or disatereomer in the product composition being greater than the ratio of second to first enantiomer or disatereomer in the enantiomerically enriched composition. Preferred catalyst systems include transition metal halide complex of the formula MnXpYr wherein M is a transition metal; X is a halide; Y is a neutral optionally substituted hydrocarbyl complexing group, a neutral optionally substituted perhalogenated hydrocarbyl complexing group, or an optionally substituted cyclopentadienyl complexing group; and n, p and r are integers. The reaction promoter is preferably a halide salt.
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Page/Page column 22-23
(2008/06/13)
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- Efficient kinetic resolution in hydroboration of 1,2-dihydronaphthalenes
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1-Substituted 1,2-dihydronaphthalenes undergo kinetic resolution during asymmetric hydroboration with Rh-QUINAP complexes.
- Maeda, Kenji,Brown, John M.
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p. 310 - 311
(2007/10/03)
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- Efficient kinetic resolution in the asymmetric hydrosilylation of imines of 3-substituted indanones and 4-substituted tetralones
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Kinetic resolution of the N-methyl imines of 3-substituted indanones and 4-substituted tetralones could be accomplished by hydrosilylation with a chiral titanocene catalyst. N-Methyl imines of 4-substituted tetralones were resolved to yield, after hydrolysis of the unreacted starting materials, ketones with high ee's and the amine products with high diastereomeric and enantiomeric purity. The utility of this process was demonstrated in the synthesis of sertraline.
- Yun, Jaesook,Buchwald, Stephen L.
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p. 767 - 774
(2007/10/03)
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- Nontricyclic Antidepressant Agents Derived from cis- and trans-1-Amino-4-aryltetralins
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The need for drugs that lack the obtrusive and limiting side effects of the tricyclic antidepressants has prompted the search for agents with greatly enhanced selectivity for specific mechanisms believed to be essential for antidepressant efficacy.The potential role of derangements of 5-HT pathways in the etiology of depression has long been suspected and has given impetus to the development of newer compounds that accentuate inhibition of serotonin reuptake.This paper presents structure-activity relationship for a series of cis-1-amino-4-(substituted-aryl)tetralins, which are surprisingly potent and selective inhibitors of serotonin uptake in in vitro models.These compounds are pharmacologically distinct from corresponding members of the trans series, which also potently block uptake of dopamine and norepinephrine.The activity in both cis and trans series is stereospecific, being restricted to the cis-(1S,4S) and the trans-(1R,4S) enantiomers.
- Welch, Willard M.,Kraska, Allen R.,Sarges, Reinhard,Koe, B. Kenneth
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p. 1508 - 1515
(2007/10/02)
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