109-01-3Relevant articles and documents
Mechanisms of acid decomposition of dithiocarbamates. 5. Piperidyl dithiocarbamate and analogues
Humeres, Eduardo,Byung, Sun Lee,Debacher, Nito Angelo
, p. 7189 - 7196 (2008)
(Chemical Equation Presented) In this work, the acid cleavage at 25°C in 20% v/v aqueous ethanol of a series of analogues of piperidine dithiocarbamate X(C2H4)2NCS2 - (X = CH2, CHCH3, NH, NCH3, S, O) was studied. The pH-rate profiles were obtained in the range of Ho -5 and pH 5. They all presented a dumbell shaped curve with a plateau from which the pH-independent first-order rate constant ko (or the specific acid catalysis kH) was calculated, in addition to the acid dissociation constant of the free (pKa) and conjugate acid (pK+) species of the DTC. LFERs of the kinetically determined pKa and pK+ versus pKN (pKa of parent amine) were used to characterize the reactive species and the structure of the transition state of the rate-determining step. For X = CH2, CH3CH the values of kH agree with those of alkDTCs in the strong base region of the Bronsted plot of log kH versus pKN where the transition state is close to a zwitterion formed by intramolecular water-catalyzed S-to-N proton transfer of the dithiocarbamic acid. However, when X = NH, CH3N, O, S, the reactive species is the DTC anion, which is as reactive as an arylDTC, and similarly, the pK+ values correspond to a parent amine that is about 3-4 pK units more basic. The solvent isotope effect indicated that the acid decomposition of these dithiocarbamate anions is specifically catalyzed by a Hydron anchimerically assisted by the heteroatom through a boat conformation.
Selective reduction of N-nitroso aza-aliphatic cyclic compounds to the corresponding N-amino products using zinc dust in CO2–H2O medium
Yang, Weiqing,Lu, Xiang,Zhou, Tingting,Cao, Yongjing,Zhang, Yuanyuan,Ma, Menglin
, p. 780 - 783 (2018)
[Figure not available: see fulltext.] A new method for reduction of N-nitroso aza-aliphatic cyclic compounds employing zinc in pressurized CO2–H2O medium has been developed. H2O and NH4Cl were used as hydrogen donors, and reduction was performed under environmentally benign conditions. The presented approach allowed to obtain the respective N-amino products selectively and in excellent yields (up to 97%).
Study of the formation and thermal decomposition of an azo-bridged tricyclic ring system
Novak, Zoltan,Vincze, Zoltan,Czegeny, Zsuzsanna,Magyarfalvi, Gabor,Smith, David M.,Kotschy, Andras
, p. 3358 - 3363 (2006)
1-Amino-2-methyl-1,3-pentadienes were treated with dimethyl 1,2,4,5-tetrazine-3,6-dicarboxylate to give diazatricyclo[2.2.2.0]octenes and dimethyl 4-methylpyridazine-3,6-dicarboxylate, the product distribution being largely dependent on the nature of the amino substituent. Under similar conditions the analogous 1-morpholino-1,3-butadiene afforded dimethyl pyridazine-3,6-dicarboxylate as the major product. The tricyclic products underwent selective thermal decomposition to give dimethyl 4-methylpyridazine-3, 6-dicarboxylate in excellent yield. The proposed mechanism of the formation as well as of the decomposition was supported by quantum chemical calculations and experimental evidence. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Nickel-Catalyzed Amination of Aryl Chlorides with Amides
Li, Jinpeng,Huang, Changyu,Wen, Daheng,Zheng, Qingshu,Tu, Bo,Tu, Tao
supporting information, p. 687 - 691 (2021/01/09)
A nickel-catalyzed amination of aryl chlorides with diverse amides via C-N bond cleavage has been realized under mild conditions. A broad substrate scope with excellent functional group tolerance at a low catalyst loading makes the protocol powerful for synthesizing various aromatic amines. The aryl chlorides could selectively couple to the amino fragments rather than the carbonyl moieties of amides. Our protocol complements the conventional amination of aryl chlorides and expands the usage of inactive amides.
Method for synthesizing 1-amino-4-methylpiperazine through catalytic hydrogenation
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Paragraph 0044-0046; 0068, (2020/07/28)
The invention relates to a method for synthesizing 1-amino-4-methylpiperazine through catalytic hydrogenation. The invention discloses the green synthesis method for synthesizing 1-amino-4-methylpiperazine by hydrogenating 1-methyl-4-nitrosopiperazine in a water and organic mixed solvent system under the catalysis of an iron oxide and ferrous oxide supported palladium catalyst, wherein the methodcomprises the steps: adding 1-methyl-4-nitrosopiperazine into a paramagnetic Pd/Fe3O4-FeO catalyst, carrying out a hydrogenation reaction in a three-phase system of water, an organic solvent and the catalyst at a certain temperature, and finally, carrying out reduced pressure distillation separation to obtain the target product 1-amino-4-methylpiperazine. The 1-amino-4-methylpiperazine is preparedby innovatively using a catalytic hydrogenation method in a three-phase system, and compared with a traditional synthesis method, the method is more environmentally friendly and safer, and the cost is saved.
Biocatalytic Access to Piperazines from Diamines and Dicarbonyls
Borlinghaus, Niels,Gergel, Sebastian,Nestl, Bettina M.
, p. 3727 - 3732 (2018/04/14)
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.
A catalytic hydrogenation preparing piperazine or alkyl piperazine method
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Paragraph 0038-0039, (2017/04/26)
The invention discloses a method for preparing piperazidine or alkyl piperazidine by catalytic hydrogenation, which comprises the following steps: carrying out catalytic hydrogenation reaction on raw materials dihydroxy ethyl piperazidine or/and hydroxyethyl piperazidine under the action of a catalyst, and carrying out after-treatment to obtain the piperazidine or/and alkyl piperazidine, wherein the active component in the catalyst is one or more of Cu, Ni and Co. The dihydroxy ethyl piperazidine or hydroxyethyl piperazidine is used as the raw material to prepare the piperazidine or alkyl piperazidine by catalytic hydrogenation, thereby providing a brand-new synthesis technique of piperazidine or alkyl piperazidine. Meanwhile, the method can be utilized to implement the recovery of the waste liquor or byproduct containing dihydroxy ethyl piperazidine or hydroxyethyl piperazidine. Besides, the existing method can be utilized to separate the alkyl piperazidine in the product, thereby further enhancing the value of the product and lowering the preparation cost.
N-methyl piperazine a process for the preparation of (by machine translation)
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Paragraph 0066-0074, (2019/02/02)
The invention relates to a preparation method of N-methyl piperazine. The preparation method comprises the following steps: (1) carrying out reaction on iminodiacetonitrile (IDAN) and methanal under the acidic condition to prepare N-methyl iminodiacetonitrile; and (2) carrying out hydrogenation reaction on N-methyl iminodiacetonitrile at the temperature of 70-140 DEG C and the pressure of 2-8MPa, wherein a molecular-sieve modified zirconium-based superacid serves a carrier, and one or two or more of the active metals of Fe, Co, Ni, Ru and Rh serves/serve as a hydrogenation catalyst. Compared with the prior art, the preparation method provided by the invention has the advantages of high yield due to the adoption of the catalyst and low equipment investment. In addition, the raw materials for preparing the N-methyl piperazine are low in cost and are easy to obtain.
A method of manufacturing a mono-N-alkyl-piperazinecarboxylic
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Paragraph 0086-0089, (2018/11/22)
The invention relates to a method for producing a mono-N-alkyl piperazine of formula (I), where R1 represents C1 to C5 alkyl or 2-(2-hydroxy-ethoxy) ethyl, by reacting diethanolamine (DEOA) of formula (II) with a primary amine of formula H2N-R1 (III) in the presence of hydrogen and a supported catalyst containing metal. The catalytically active mass of the catalyst, before reduction of the latter using hydrogen, contains oxygenic compounds of aluminum, copper, nickel and cobalt and between 0.2 and 5.0 wt. % oxygenic compounds of tin, calculated as SnO, and the reaction is carried out in the liquid phase at an absolute pressure ranging from 95 to 145 bar.
PROCESS FOR THE PREPARATION OF A MONO-N-ALKYLPIPERAZINE
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Paragraph 0093, (2014/01/07)
Process for the preparation of a mono-N-alkylpiperazine of the formula I in which R1 is C1- to C5-alkyl or 2-(2-hydroxyethoxy)ethyl, by reacting diethanolamine (DEOA) of the formula II with a primary amine of the formula H2N—R1 (III) in the presence of hydrogen and a catalyst molding, where the reaction is carried out in the liquid phase at an absolute pressure in the range from 150 to 250 bar and the amination is carried out by means of a catalyst molding, the precursor of which can be prepared according to a process in which (i) an oxidic material comprising copper oxide, aluminum oxide and lanthanum oxide is provided,(ii) pulverulent metallic copper and/or copper flakes and optionally graphite is added to the oxidic material,(iii) the mixture resulting from step ii is shaped to give a molding, where the oxidic material is obtainable by simultaneous or successive precipitation of the component copper oxide, of the component aluminum oxide and of the component lanthanum oxide and subsequent drying and calcination and, after the shaping according to step iii, the catalyst molding is calcined again.
