593-56-6Relevant articles and documents
Vinylogous Aza-Michael Addition of Urea Derivatives with p-Quinone Methides Followed by Oxidative Dearomative Cyclization: Approach to Spiroimidazolidinone Derivatives
Kaur, Navpreet,Singh, Priyanka,Banerjee, Prabal
supporting information, p. 2813 - 2824 (2021/04/21)
Herein, we report an efficient protocol for the synthesis of spiro-imidazolidinone-cyclohexadienones from p-quinone methides (p-QMs) and dialkyloxy ureas under mild conditions. The strategy follows a two-step process involving an initial vinylogous conjugate addition of urea derivatives to p-QMs, followed by oxidative dearomative cyclization of open-chain product to the projected spiro-imidazolidinones. This protocol exhibits good functional group tolerance and provides a straightforward method to access spiro-imidazolidinone-cyclohexadienones. In follow-up chemistry, we have shown the debenzylation of spiroimidazolidinones to give N-hydroxycyclic ureas. (Figure presented.).
Preparation method of methoxyamine hydrochloride
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Paragraph 0022; 0030; 0038, (2021/09/21)
The invention relates to the field of chemical industry, and provides a preparation method of methoxyamine hydrochloride, which comprises the steps of etherification reaction, rectification separation, hydrolysis reaction, crystallization drying and the like. According to the method, firstly, acetoxime, methane chloride and caustic soda flakes are subjected to an etherification reaction under the action of a catalyst to generate acetoxime methyl ether, then the acetoxime methyl ether is subjected to a hydrolysis reaction under the condition of diluted hydrochloric acid to generate the product methoxyamine hydrochloride, the reaction raw materials are cheap and easy to obtain, the reaction conditions are mild, operation is easy, synthesis is easy, the by-product acetone can be recycled, so that the cost and the energy consumption can be reduced; the etherification reaction is carried out under the action of the immobilized solid base catalyst, compared with the prior art, the yield of the reaction is high, the material utilization rate is large, and the preparation method of the methoxyamine hydrochloride has an industrial prospect.
One-pot method for preparing O-alkyl hydroxylamine hydrochloride and N,O-dialkyl hydroxylamine hydrochloride
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Paragraph 0038-0039, (2020/10/20)
The invention relates to the field of organic synthesis, in particular to a one-pot method for preparing O-alkyl hydroxylamine hydrochloride and N,O-dialkyl hydroxylamine hydrochloride. The method comprises the following steps: S1, acetylation: mixing hydroxylamine hydrochloride with water and methyl acetate, and dropwise adding a sodium hydroxide solution while stirring at room temperature to obtain an intermediate acetyl hydroxylamine; S2, alkylation: dropwise adding an alkylation reagent into the reaction kettle at normal temperature, and then heating the reactants for reaction; S3, hydrolysis and purification: after the reaction is qualified, adding concentrated sulfuric acid, performing heating hydrolysis, after the reaction is qualified, adding caustic soda flakes or liquid caustic soda to adjust the pH value to 12, carrying out atmospheric distillation and hydrochloric acid acidification, cooling the product for crystallization, and centrifuging and drying the crystal to obtaina final product. According to the invention, methyl acetate is used as an acetyl protective agent, and compared with ethyl acetate, methyl acetate has the advantages of good water solubility, small reaction steric hindrance, sufficient protection, few impurities, low price and cost and the like; therefore, the method has the advantages of high product purity, simple process operation, accessible raw materials, simple wastewater components and environment friendliness, and is suitable for industrial production.
