- Biocatalytic Access to Piperazines from Diamines and Dicarbonyls
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Given the widespread importance of piperazines as building blocks for the production of pharmaceuticals, an efficient and selective synthesis is highly desirable. Here we show the direct synthesis of piperazines from 1,2-dicarbonyl and 1,2-diamine substrates using the R-selective imine reductase from Myxococcus stipitatus as biocatalyst. Various N- and C-substituted piperazines with high activity and excellent enantioselectivity were obtained under mild reaction conditions reaching up to 8.1 g per liter.
- Borlinghaus, Niels,Gergel, Sebastian,Nestl, Bettina M.
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p. 3727 - 3732
(2018/04/14)
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- The Absolute Configurations of (+)- and (-)-2-Methylpiperazines and their N-Methyl Derivatives.
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S(-)-2-Methylpiperazinium dichloride was prepared by reduction of S(-)-3-methyl-2,5-dioxopiperazine (from glycyl-S-alanine) which established its absolute configuration.This dichloride and its enantiomer, R(+)-2-methylpiperazinium dichloride, were obtained in less optically pure forms by recrystallization of the diastereomeric RS-2-methylpiperazinium 2R,3R-di-O-benzoyltartrate salts followed by decomposition with a base.They were converted into S(+)- and R(-)-1,2,4-trimethylpiperazinium dichloride, S(+)- and R(-)-1,2,4,4-tetramethylpiperazinium iodide and S(+)- and R(-)-1,1,2,4,4-pentamethylpiperazinium diiodide.
- Armarego, Wilfred L. F.,Schou, Henning,Waring, Paul
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p. 1951 - 1966
(2007/10/02)
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