- Preparation method, product and application of 2-amino-5-methylpyrazine
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The invention belongs to the field of chemical synthesis, and relates to a preparation method, product and application of 2-amino-5-methylpyrazine. The preparation method comprises the following steps: reacting 2-aminomalonamide with pyruvic aldehyde to generate 2-methyl-5-hydroxy-4-pyrazinamide; enabling 2-methyl-5-hydroxy-4-pyrazinamide to react with phosphorus oxychloride so as to generate 2-methyl-5-chloro-4-cyanopyrazine; carrying out a hydrogenation reaction on the 2-methyl-5-chloro-4-cyanopyrazine to generate 2-methyl-4-cyanopyrazine, and hydrolyzing the 2-methyl-4-cyanopyrazine to obtain 2-methyl-4-amide pyrazine; and carrying out Hofmann degradation on the 2-methyl-4-amide pyrazine so as to obtain the 2-methyl-5-aminopyrazine. The method belongs to a brand-new 2-amino-5-methylpyrazine preparation method, is simple and convenient to operate, high in yield and low in cost, and is suitable for industrial large-scale production.
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Paragraph 0037; 0042-0043; 0048; 0053-0054; 0059; 0064-0065
(2020/11/25)
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- Studies on Pyrazines. Part 22. Lewis Acid-Mediated Cyanation of Pyrazine N-Oxides with Trimethylsilyl Cyanide: New Route to 2-Substituted 3-Cyanopyrazines
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Reaction of 3-substituted pyrazine 1-oxides with trimethylsilyl cyanide in the presence of triethylamine in acetonitrile gave the corresponding cyanopyrazines, yields of which depended remarkably on the substituent.Electron-donating groups enhanced the cyanation with high regioselectivity to 2-substituted 3-cyanopyrazines, while a chloro substituent suppressed the conversion.Addition of zinc halide to the reaction mixture, in most cases, increased the reactivity and improved the regioselectivity.On the other hand, the N-oxides carrying an electron-withdrawing methoxycarbonyl or N-butylcarbamoyl group underwent the cyanation, without need for the Lewis acid, to provide a mixture of nearly equal amounts of 2-substituted 3- and 5-cyanopyrazines.The latter compound was exclusively obtained when 3-methoxycarbonyl- or 3-cyanopyrazine 1-oxide was treated with diethoxyphosphoryl cyanide.
- Sato, Nobuhiro,Shimomura, Yuji,Ohwaki, Yoshie,Takeuchi, Ryo
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p. 2877 - 2882
(2007/10/02)
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