- Synthesis method of DL-cysteine
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The invention discloses a synthetic method of DLcysteine. The method comprises the following steps: by using acrylonitrile as a raw material, chlorinating to generate 2, 3dichloropropionitrile, hydrolyzing to generate corresponding acid, reacting the acid with thiourea to cyclize to generate 2-aminothiazoline-4-carboxylic acid, adding alkali sulfide to generate 2-mercaptothiazoline-4-carboxylic acid, and hydrolyzing to generate cysteine. The synthesis method provided by the invention has the advantages of short synthesis steps, mild preparation conditions, sufficient and cheap raw material sources and higher product yield.
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Paragraph 0020-0022
(2021/02/13)
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- Preparation method of 3-aminoisoxazole
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The invention belongs to the technical field of medicines, and particularly relates to a preparation method of 3aminoisoxazole, which comprises the following steps: (1) preparing 2, 3dichloropropionitrile: adding acrylonitrile, N, Ndimethylformamide and pyridine into a reaction vessel, cooling to 5-15 DEG C, introducing chlorine into the reaction vessel, and keeping the reaction temperature at 1020 DEG C; controlling the temperature to be 15-25 DEG C and stirring for 5 hours after the chlorine gas is introduced; blowing excessive chlorine until the reaction liquid is yellowish or colorless andtransparent to obtain 2, 3dichloropropionitrile; and (2) preparation of 3amino isoxazole: under an alkaline condition, synthesizing 3amino isoxazole by taking hydroxyurea and 2, 3dichloropropionitrile as raw materials and N, Ndimethylformamide as a catalyst. The preparation method is used for solving the technical problems of extremely easy material punching and high process risk caused by the adoption of a 2, 3dibromopropionitrile intermediate in the existing 3amino isoxazole preparation.
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Paragraph 0038-0040; 0043-0044; 0047-0048; 0051-0052
(2020/12/30)
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- The photochemical and thermal decomposition of azidoacetylene in the gas phase, solid matrix, and solutions
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Decomposition of the extremely explosive and unstable parent compound of 1-azidoalkynes, HCCN3 (azidoacetylene), was studied in the gas phase, solid argon matrix, and solutions. In the gas phase, this azide decomposes quickly at room temperature with a half-life time (t1/2) of 20 min at an initial pressure (p0) of 0.8 mbar. The decay (p0 = 1.0 mbar) is significantly increased in an atmosphere of O2 with t 1/2 of 3 min, in which HC(O)CN was identified as the trapping product of the cyanocarbene intermediate HCCN. Trapping products of this carbene by solvent molecules (CH2Cl2 and CHCl3) were also found during decomposition of the azide in solution, whereas the reaction with a solution of bromine to form dibromoacetonitrile is interpreted as taking place by nucleophilic attack of the alkyne itself. The intermediary formation of triplet HCCN by flash vacuum pyrolysis and photolysis (255 nm) of the azide in the gas phase and in solid argon matrices, respectively, was confirmed by IR spectroscopy and mutual photo-interconversion of HCCN with isomeric cyclo-C(H)CN (azirinylidene) and HCNC by selective irradiations at 16 K. Although azidoacetylene is highly explosive, it can be irradiated in an argon matrix to generate cyanocarbene. The same species is also formed and analyzed after flash vacuum pyrolysis under relatively mild conditions. Decomposition of the azide in solution is combined with trapping reactions. Copyright
- Zeng, Xiaoqing,Beckers, Helmut,Seifert, Jennifer,Banert, Klaus
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p. 4077 - 4082
(2014/07/08)
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- Process for the production of 2,3-dichloropropionitrile
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In a process for the production of 2,3-dichloropropionitrile by the chlorination of acrylonitrile, the improvement which comprises chlorinating acrylonitrile in the presence of pyridine or an alkylpyridine in combination with an alkaline earth metal carbonate.
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