- 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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- METHOD FOR PRODUCING OPTICALLY ACTIVE 2-METHYLPIPERAZINE
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PROBLEM TO BE SOLVED: To provide a method capable of industrially obtaining an optically active 2-methylpiperazine which is easy in handling and has good properties, instead of the isolation method of an optically active 2-methylpiperazine by conventional distillation. SOLUTION: There is provided a method for producing an optically active 2-methylpiperazine by adding a solvent to a solution of an optically active 2-methylpiperazine, followed by solvent substitution and crystallization to obtain crystals of the optically active 2-methylpiperazine. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0046-0052
(2017/01/26)
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- A bifunctional PdVMgO solid catalyst for the one-pot selective N-monoalkylation of amines with alcohols
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It has been found that a bifunctional metal Pd/base (MgO) catalyst performs the selective monoalkylation of amines with alcohols. The reaction goes through a series of consecutive steps in a cascade mode that involves: 1) the abstraction of hydrogen from the alcohol that produces the metal hydride and the carbonyl compound; 2) condensation of the carbonyl with the amine to give an imine, and 3) hydrogenation of the imine with the surface hydrogen atoms from the metal hydride. Based on isotopic and spectroscopic studies and on the rate of each elementary step, a global reaction mechanism has been proposed. The controlling step of the process is the hydride transfer from the metal to the imine. By changing the crystallite size of the Pd, it is demonstrated that this is a structure-sensitive reaction, whereas the competing processes that lead to subproducts are not. On these bases, a highly selective catalyst has been obtained with Pd crystallite size below 2.5 nm in diameter. The high efficiency of the catalytic system has allowed us to extend the process to the one-pot synthesis of piperazines.
- Corma, Avelino,Rodenas, Tania,Sabater, Maria J.
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supporting information; experimental part
p. 254 - 260
(2010/03/26)
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- A novel and facile method to synthesize (R)- and (S)-2-methylpiperazine
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A concise and efficient synthesis of (R)- and (S)-2-methylpiperazine in only five steps from (D)- and (L)-alanine is described. The key step is reaction of benzylamine with a bifunctional molecule to build a six-membered ring.
- Liu, Bo,Xu, Guang-Yu,Yang, Chun-Hao,Wu, Xi-Han,Xie, Yu-Yuan
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p. 4111 - 4118
(2007/10/03)
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- NOVEL PROCESS
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The present invention relates to a process for the preparation of compounds which are therapeutically active in the central nervous system. In one aspect, the invention relates to a process for the preparation of compounds of the general formula (I). The invention also relates to (2R)-1-(3-chloro-2-pyrazinyl)-2-methylpiperazine, hydrochloride and a process for preparing the same. Another object of the present invention is a compound of the formula (I). Another object of the present invention is a method for the treatment or prophylaxis of a serotonin-related disorder, comprising administering to a subject in need thereof an effective amount of the compound above; as well as the use of said compound to manufacture a medicament for the treatment of a serotonin-related disorder.
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- Asymmetric synthesis. XXXI. Synthesis of 2-substituted piperazines from chiral non-racemic lactams
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The preparation of lactam 2 from R-(-)-phenylglycinol and N-Boc glycine is described. Diastereoselective alkylation of 2 allowed the preparation of piperazine derivatives in an optically pure form.
- Schanen, Vincent,Riche, Claude,Chiaroni, Angele,Quirion, Jean-Charles,Husson, Henri-Philippe
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p. 2533 - 2536
(2007/10/02)
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- Synthesis, Antibacterial Activities, and Pharmacological Properties of Enantiomers of Temafloxacin Hydrochloride
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Temafloxacin hydrochloride is a potent member of the 4-pyridone-3-carboxylic acid class of antibacterial agents and is currently under clinical development as a broad-spectrum antimicrobial agent.It is a racemate having a chiral center at the C3 of the 7-piperazin-1-yl group.The two enantiomers were synthesized and tested for their antibacterial activities.Although no difference in in vitro antibacterial activities was observed, a minor difference in in vivo antibacterial activities was observed.However, they both exhibited similar pharmacological profiles.
- Chu, Daniel T. W.,Nordeen, Carl W.,Hardy, Dwight J.,Swanson, Robert N.,Giardina, William J.,et al.
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p. 168 - 174
(2007/10/02)
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- Optical Resolution of 2-Methylpiperazine by Complex Formation with Optically Active 1-Phenyl-1-(o-chlorophenyl)prop-2-yn-1-ol and 1,6-Diphenyl-1,6-di(o-chlorophenyl)hexa-2,4-diyne-1,6-diol
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An efficient optical resolution of 2-methylpiperazine was achieved by complex formation with the title host compounds.X-Ray crystal structure of a 1:2 complex of (S)-(+)-piperazine and (R)-(-)-1-phenyl-1-(o-chlorophenyl)prop-2-yn-1-ol was studied.
- Toda, Fumio,Tanaka, Koichi,Kido, Masaru
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p. 513 - 516
(2007/10/02)
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