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.
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Dorokhova et al.
, (1974)
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Chase,Downes
, p. 3874,3876 (1953)
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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.
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.