- The kinetics and mechanism of the organo-iridium catalysed racemisation of amines
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The dimeric iodo-iridium complex [IrCp?I2]2 (Cp? = pentamethylcyclopentadiene) is an efficient catalyst for the racemisation of secondary and tertiary amines at ambient and higher temperatures with a low catalyst loading. The racemisation occurs with pseudo-first-order kinetics and the corresponding four rate constants were obtained by monitoring the time dependence of the concentrations of the (R) and (S) enantiomers starting with either pure (R) or (S) and show a first-order dependence on catalyst concentration. Low temperature 1H NMR data is consistent with the formation of a 1 : 1 complex with the amine coordinated to the iridium and with both iodide anions still bound to the metal-ion, but at the higher temperatures used for kinetic studies binding is weak and so no saturation zero-order kinetics are observed. A cross-over experiment with isotopically labelled amines demonstrates the intermediate formation of an imine which can dissociate from the iridium complex. Replacing the iodides in the catalyst by other ligands or having an amide substituent in Cp? results in a much less effective catalysts for the racemisation of amines. The rate constants for a deuterated amine yield a significant primary kinetic isotope effect kH/kD = 3.24 indicating that hydride transfer is involved in the rate-limiting step.
- Stirling, Matthew J.,Mwansa, Joseph M.,Sweeney, Gemma,Blacker, A. John,Page, Michael I.
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- Development of [3]ferrocenophane-derived N/B frustrated Lewis pairs for the metal-free catalytic hydrogenation of imines
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A series of novel [3]ferrocenophane-derived N/B frustrated Lewis pairs (FLPs) were synthesized and successfully applied to the catalytic hydrogenation of imines in 71–93% yields. This approach could be easily conducted on gram scale and provided versatile synthetic route for the key intermediate of sertraline hydrochloride without heavy metal residues.
- Pan, Zhentao,Wang, Hui,Ling, Fei,Xiao, Lian,Song, Dingguo,Zhong, Weihui
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p. 522 - 528
(2019/02/01)
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- Protic additives or impurities promote imine reduction with pinacolborane
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We report here that addition of stoichiometric amounts of alcohols or water to mixtures of imines and pinacolborane promote reduction reactions. The reactions of several imines were examined, revealing that alkyl imines were reduced, while aniline derived imines were not effectively reduced. The use of binol as an additive resulted in modest enantioinduction, however other chiral additives that were screened gave negligible enantioinduction. While the reactions described herein are not competitive in conversion with established imine reduction technologies, this work reveals that the presence of protic impurities must be considered as a promoter of side reactions in catalyzed imine hydroborations. Amines also promote imine reduction in certain cases, raising the possibility of a slow autocatalytic reaction. The ability of water or other protic impurities to promote the reduction of imines with pinacolborane represents an important identification of a potential source of background reaction in catalyzed reductions of imines.
- Huchenski, Blake S. N.,Speed, Alexander W. H.
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supporting information
p. 1999 - 2004
(2019/02/20)
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- Metal-free transfer hydrogenation catalysis by B(C6F 5)3
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The activation of amines by B(C6F5)3 is shown to effect the catalytic racemization of a chiral amine. Extending this strategy to a bimolecular process, catalytic transfer hydrogenation of imines, enamines, and N-heterocycles is demonstrated using iPr2NH as the source of hydrogen and a catalytic amount of the Lewis acid B(C 6F5)3.
- Farrell, Jeffrey M.,Heiden, Zachariah M.,Stephan, Douglas W.
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experimental part
p. 4497 - 4500
(2011/11/04)
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- IMPROVED MANUFACTURING PROCEDURE FOR THE PREPARATION OF POLYMORPHIC FORM II OF CIS-(1S)-N-METHYL-4-(3,4-DICHLOROPHENYL)-1,2,3,4-TETRAHYDRO-1-NAPTHLENEAMINE HYDROCHLORIDE (SERTRALINE HYDROCHLORIDE)
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The present invention relates to the improved, scalable and efficient manufacturing procedure for the preparation of the antidepressant Cis-(1S)-N-Methyl-4-(3,4-Dichlorophenyl)-1,2,3,4-tetrahydro-1-napthaleneamine hydro chloride, Sertraline Hydrochloride polymorphic form II. The present invention further relates to the improved and modified procedures for preparing, separating and isolating the key intermediates involved in the preparationof Sertraline Hydrochloride polymorphic form II. The present invention also further relates to the use of novel reagents or a combination thereof and new methodologies to prepare some o'f the key intermediates involved in the preparation of Polymorphic Form II of Sertraline Hydrochloride.
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Page/Page column 23
(2008/06/13)
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- Continuous flow hydrogenation of a pharmaceutical intermediate, [4-(3,4-dichlorophenyl)-3,4-dihydro-2H-naphthalenyidene]-methylamine, in supercritical carbon dioxide
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The hydrogenation of complex pharmaceutical intermediate, rac-sertraline imine has been optimized as a continuous flow process utilizing a palladium/calcium carbonate (Pd/CaCO3) catalyst and hydrogen in supercritical carbon dioxide (scCO2
- Clark, Peter,Poliakoff, Martyn,Wells, Andy
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p. 2655 - 2659
(2008/09/19)
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- Method for preparing sertraline
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(1S-cis)-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-N-methyl-1-naphthalenamine (sertraline) may be prepared by hydrogenating of N-[4-(3,4-dichlorophenyl)-3,4-dihydro-1(2H)-naphthalenylidene]methanamine in the presence of a dehalogenation inhibitor, e.g., t
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- PROCESS FOR THE MANUFACTURE OF SERTRALINE
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Process for the preparation of sertraline by reductive amination of racemic 4-(3, 4-dichlorophenyl)-3, 4-dihydro-1-(2H)-naphthalenone, carried out as one- reaction-vessel process without isolation of intermediates, in the form of pure separated cis and trans isomers, the way of conversion of trans isomer to cis isomer and preparation of FII polymorph of 1S-cis isomer from any other polymorph.
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- Use of 4-phenyl-1,2,3,4-tetrahydro-1-naphthalenamine derivatives in the treatment of psychosis, inflammation and as immunosuppressants
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4-Phenyl-1,2,3,4-tetrahydro-1-naphthalenamine derivatives have been found useful for the treatment of psychosis, inflammation and as immunosuppressants.
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