- Synthesis method of N-hydroxyethyl-5-amino-1H pyrazole
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The invention discloses a synthesis method of N-hydroxyethyl-5-amino-1H pyrazole. The synthesis method comprises the following steps: by taking N, N-dimethylformamide as a raw material, carrying out one-pot reaction on the N, N-dimethylformamide, dimethyl sulfate and cyanoacetic acid R ester to prepare 2-cyano-3-(dimethylamino) acrylic acid R ester; carrying out cyclization and hydrolysis on the 2-cyano-3-(dimethylamino) acrylic acid R ester and beta-hydroxyethylhydrazine to prepare N-hydroxyethyl-5-amino-1H pyrazole-4-formic acid; and carrying out decarboxylation on N-hydroxyethyl-5-amino-1H pyrazole-4-formic acid, so as to prepare N-hydroxyethyl-5-amino-1H pyrazole, wherein R is an alkane group below C4. The synthesis method provided by the invention has the advantages of strong operability, high economic benefit and high yield.
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Paragraph 0037; 0040-0041; 0065; 0068-0069
(2021/07/21)
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- Preparation of 4,5-diamino-1-(2'-hydroxyethyl)-pyradazole and acid addition salts thereof
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Disclosed is an improved process for the preparation of 4,5-diamino-1-(2'-hydroxyethyl)pyrazole and acid addition salts thereof such as the addition salt from sulfuric acid. The process comprises a novel combination of steps beginning with an alkyl (alkoxymethylene)cyanoacetate and 2-hydroxyethylhydrazine and the formation of intermediate compounds 5-amino-4-alkoxycarbonyl-1-(2'-hydroxyethyl)pyrazole (I), 5-amino-4-carboxyl-1-(2'-hydroxyethyl)pyrazole (II), 5-amino-1-(2'-hydroxyethyl)pyrazole (III), 5-amino-1-(2'-hydroxyethyl)4-nitrosopyrazole (IV),
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- Preparation of 4,5-diamino-1-(2′-hydroxyethyl)-pyrazole and acid addition salts thereof
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Disclosed is an improved process for the preparation of 4,5-diamino-1-(2′-hydroxyethyl)pyrazole and acid addition salts thereof such as the addition salt from sulfuric acid. The process comprises a novel combination of steps beginning with an alkyl(alkoxymethylene)cyanoacetate and 2-hydroxyethylhydrazine and the formation of intermediate compounds 5-amino-4-alkoxycarbonyl-1-(2′-hydroxyethyl)pyrazole (I), 5-amino-4-carboxyl-1-(2′-hydroxyethyl)pyrazole (II), 5-amino-1-(2′-hydroxyethyl)pyrazole (III), 5-amino-1-(2′-hydroxyethyl)4-nitrosopyrazole (IV).
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