- Preparation method of 4,5-diamino-1-(2-hydroxyethyl)pyrazole sulfate
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The invention relates to a preparation method of 4,5-diamino-1-(2-hydroxyethyl)pyrazole sulfate. Diethyl ethoxymethylenemalonate is taken as an initial raw material and cyclized with 2-hydroxyethyl inethyl alcohol, and then the 4,5-diamino-1-(2-hydroxyethyl)pyrazole sulfate is prepared through hydrolysis, acidization, decarboxylation, nitrosation, reduction and sulfuric acid salifying. Accordingto the preparation method of the 4,5-diamino-1-(2-hydroxyethyl)pyrazole sulfate, by-products are few, a prepared product is high in purity, meanwhile a process is simplified, the synthesis period is shortened, and meanwhile expansion and popularization are also facilitated.
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Paragraph 0007
(2019/11/18)
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- Preparation of 4,5-diamino-1-(substituted)-pyrazole and acid addition salts thereof
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Disclosed is an improved process for the preparation of 4,5-diamino-1-(substituted)pyrazoles and acid addition salts thereof by coupling the corresponding 5-amino-1-(substituted)pyrazole with an aromatic diazonium compound to produce an intermediate azo compound and contacting the intermediate azo compound with hydrogen in the presence of a hydrogenation catalyst to produce 4,5-diamino-1-(substituted)pyrazoles. Also disclosed is a decarboxylation process for the preparation of a 5-amino-1-(substituted)pyrazole by heating a solution comprising a 5-amino-4-carboxy-1-(substituted)pyrazole, an inorganic acid and an inert solvent.
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Page/Page column 5
(2010/11/25)
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- CEPHEM COMPOUNDS
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The present invention relates to a compound of the formula [I]: wherein R1 is lower alkyl, hydroxy(lower)alkyl or halo(lower)alkyl, and R2 is hydrogen or amino protecting group, or R1 and R2 are bonded together and form lower alkylene or lower alkenylene; R3 is hydrogen or lower alkyl; R4 is ; R5 is carboxy or protected carboxy; and R6 is amino or protected amino, or a pharmaceutically acceptable salt thereof, a process for preparing a compound of the formula [I], and a pharmaceutical composition comprising a compound of the formula [I] in admixture with a pharmaceutically acceptable carrier.
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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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