- A chiral three-stage amine compound synthetic methods and use thereof
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The present invention provides a chiral three-stage compound synthesis method, the method is asymmetric reductive amination reaction, the use of two-stage [...] iridium catalyst in the hydrogenation reaction under the action of the chiral three levels of amine compounds, the method of preparation and chiral three levels of amine compounds can be used for anti-depression drugs and the like synthetic. The relates to chiral three-stage amides synthetic method, the secondary amine as asymmetric reductive amination of amine source, and not through the other chemical reactions by one step to obtain three levels of chiral amine; the use of phosphoramidite chiral ligand as catalyst, such chiral ligand low price, easy synthesis and expand; additive combined use can greatly improve the yield of the reaction and the enantioselectivity. From the foregoing, the method has simple operation and easy mass production advantages.
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Paragraph 0030; 0033; 0034
(2019/05/21)
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- Secondary amines as coupling partners in direct catalytic asymmetric reductive amination
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The secondary amine participating asymmetric reductive amination remains an unsolved problem in organic synthesis. Here we show for the first time that secondary amines are capable of effectively serving as N-sources in direct asymmetric reductive amination to afford corresponding tertiary chiral amines with the help of a selected additive set under mild conditions (0-25 °C). The applied chiral phosphoramidite ligands are readily prepared from BINOL and easily modified. Compared with common tertiary chiral amine synthetic methods, this procedure is much more concise and scalable, as exemplified by the facile synthesis of rivastigmine and N-methyl-1-phenylethanamine.
- Wu, Zitong,Du, Shaozhi,Gao, Guorui,Yang, Wenkun,Yang, Xiongyu,Huang, Haizhou,Chang, Mingxin
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p. 4509 - 4514
(2019/04/29)
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- IMPROVED PROCESS FOR THE PREPARATION OF RIVASTIGMINE
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The present invention relates to an improved process for preparation of Rivastigmine of formula (I) or pharmaceutically acceptable salts thereof comprising a step of N-methylation of compound of formula (III), wherein R1 = R2 = H or R1 = H and R2 = CH3 or an acid addition salt thereof, using paraformaldehyde in the presence of Raney Nickel and hydrogen in a suitable solvent to obtain compound of formula (II).
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Page/Page column 9
(2008/06/13)
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