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.
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.
