- Asymmetric Synthesis of a Key Intermediate for Tofacitinib via a Dynamic Kinetic Resolution-Reductive Amination Protocol
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We report the first example of a catalytic asymmetric reductive amination under dynamic kinetic resolution (DKR) conditions for the preparation of a chiral amine as a key intermediate toward Tofacitinib, an active pharmaceutical ingredient developed by Pfizer. Such a protocol allows the preferential formation of a single product out of four possible diastereomers of the chiral amine starting from the corresponding racemic ketone. The chiral iridium catalyst able to perform such a feast was discovered through a mix of high-throughput screening, racemization study, and reaction optimization.
- Verzijl, Gerard K. M.,Schuster, Christian,Dax, Thomas,De Vries, André H. M.,Lefort, Laurent
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- Preparation methods of tofacitinib citrate intermediate and tofacitinib citrate
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The invention discloses preparation methods of a tofacitinib citrate intermediate and tofacitinib citrate. The preparation method of the tofacitinib citrate intermediate comprises: preparing N-(1-benzyl-4-methyl-1,2,5,6-tetrahydropiperidine-3-yl)acetamide by using 3-amino-4-methyl-pyridine, acetyl chloride, benzyl chloride and sodium borohydride as raw materials; preparing 1-benzyl-N,4-dimethylpiperidine-3-amine by using the N-(1-benzyl-4-methyl-1,2,5,6-tetrahydropiperidine-3-yl)acetamide, hydrochloric acid, methylamine and sodium borohydride as raw materials; and carrying out resolution and dissociation on the 1-benzyl-N,4-dimethylpiperidine-3-amine, and carrying out salt forming with hydrochloric acid to obtain the product. The invention provides the new tofacitinib citrate intermediatepreparation method, wherein the use amount of the catalytic hydrogenation catalyst is reduced in the preparation process of tofacitinib citrate so as to reduce the cost, and the generation of N-alkylated impurities can be well controlled by adopting the isopropanol/water mixed solvent.
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- PROCESS FOR THE PREPARATION OF CHIRAL 3-AMINO-PIPERIDINS, USEFUL INTERMEDIATES FOR THE PREPARATION OF TOFACITINIB
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Object of the present invention is an improved process for the preparation of (3R,4R)-1-benzyl-4-methylpiperidin-3-amine by means of chiral Rhodium catalysts.
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- Preparation method for chiral piperylhydrazine compound and recycling method for chiral resolving agent
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The invention discloses a preparation method for a chiral piperylhydrazine compound and a recycling method for a chiral resolving agent. In the invention, 1-benzyl-4-methyl-3-pipradrol is taken as aninitial raw material and is subjected to reactions of halogenation, methylamination, chiral resolution, and the like, so as to prepare a (3R, 4R)-N,4-dimethyl-1-(phenyl methyl)-3-piperylhydrazine dihydrochloride product, and meanwhile, a resolving mother solution is subjected to alkalization, refined, purified and recycled, so as to acquire a (2R,3R)-2,3-bi[(4-methyl benzoyl) oxo] succinic acid product meeting the reaction requirement. The invention has the beneficial effects of 1) short synthetic route, easily controlled intermediate purity and benefit to the control on impurity content, and2) simple and convenient technological operation in each step reaction, capability of recycling the high-dosage chiral resolving agent, capability of reducing production cost while reducing yield of solid wastes and suitability for large-scale industrial production.
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Paragraph 0012; 0015; 0017; 0020; 0022; 0025
(2019/01/08)
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- PROCESS FOR PREPARING CHIRAL AMINES
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The invention pertains to a process for the preparation of an amine having at least two chiral centers from a ketone having a chiral center at the a position and an amine comprising the steps of: (a) contacting a ketone having a chiral center at the a position and a primary amine thereby forming an imine; (b) contacting the imine with a reducing agent in the presence of an enantioselective catalyst to form an amine having at least two chiral centers, wherein step (a) and/or step (b) are conducted under racemization-enhancing conditions, wherein the racemization-enhancing conditions are achieved by addition of an acid and/or by addition of a salt of a primary amine and an acid, which salt is added in addition to or instead of the primary amine, and wherein the reducing agent is hydrogen.
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Page/Page column 16; 17
(2018/04/17)
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- Preparation method of tofacitinib citrate
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The invention belongs to the field of medicine and chemical engineering and particularly relates to a preparation method of tofacitinib citrate. The method comprises steps as follows: 1-benzyl-4-methyl-2,6-dihydro-3-piperidone taken as a starting material is subjected to an asymmetric reduction reaction, 1-benzyl-4-methyl-3-piperidone is obtained, and (3R,4R)-cis-1-benzyl-4-methyl-3-methylamino-piperidine dihydrochloride is produced under the action of a chiral catalyst; (3R,4R)-cis-1-benzyl-4-methyl-3-methylamino-piperidine dihydrochlorid and a paratoluensulfonyl chloride protection product 4-chloro-7-(methyl-4-benzenesulfonyl) pyrrolo[2,3-d]pyrimidine of 4-chloropyrrolo[2,3-d]pyrimidine are subjected to a condensation reaction, [(3R,4R)]-1-benzyl-4-methyl-piperidine-3-yl]-methyl-(7H-pyrrolo[2,3-d]pyrimidine-4-yl)-amine is obtained through deprotection, and tofacitinib citrate is obtained through debenzylation protection, an acylation reaction and citric acid salifying. The process route is short, the process cycle is short, chiral synthesis is performed by means of a catalyst, the product purity is improved, the cost is reduced, the yield is high, and the operation is simple and convenient.
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Paragraph 0055
(2016/10/17)
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