- Preparation method of albendazole
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The invention discloses a preparation method of albendazole, which comprises the following steps of: dissolving 4-propylthio-o-phenylenediamine in methanol, cooling, keeping the temperature at 0-5 DEGC, slowly dropwise adding cyanogen chloride for reaction under the condition of uniform stirring, and regulating and keeping the pH value at 4-5 in the process; heating to 35-45 DEG C after dropwiseadding is finished, carrying out heat preservation for 1-2 hours, then carrying out atmospheric distillation to recover methanol to obtain a solid-liquid mixed aqueous solution, and carrying out cooling, filtering and drying to obtain 6-propylthio-2-amino-1-hydrogen-benzo [d] imidazole; adding the obtained product into methanol, stirring, cooling, maintaining the temperature at 5-10 DEG C, slowlydropwise adding methyl chloroformate, and adjusting and maintaining the pH value at 6-7; after dropwise adding is finished, heating to 35-45 DEG C, keeping the temperature for 1-2 hours, distilling atnormal pressure to recover methanol, cooling to 15-20 DEG C, and performing filtering and drying to obtain an albendazole product. The method has the advantages of mild process conditions, low cost of used raw materials, water saving, strong reaction activity, good selectivity, high product yield and good product quality.
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Paragraph 0057-0058
(2020/09/09)
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- Carbendazim preparation technology
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The invention discloses a carbendazim preparation method. Being improved based on a traditional synthesis technology, the carbendazim preparation method is characterized in that firstly, a methylbenzene and water biphasic solvent reaction system is adopted, so that carbendazim appearance is improved, carbendazim is bright white, purity can be above 99.8% and carbendazim grade is increased; secondly, a method that concentrated hydrochloric acid and a methyl cyanocarbamate cyclizing agent are added dropwise simultaneously is adopted, and carbendazim yield can be above 97.5%. Compared with an existing traditional synthesis technology, the carbendazim preparation method has the greatest advantages that carbendazim yield is high, and the carbendazim is excellent in color and luster and high in purity, thereby being a method capable of preparing the high-quality carbendazim.
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Paragraph 0007; 0014
(2017/01/17)
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- Synthesis and reactions of some 5(6)-(1-adamantyl)benzimidazoles
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4-(1-Adamantyl)-1,2-diaminobenzene, previously unreported in the literature, has been prepared and a novel series of 5(6)-(1-adamantyl) benzimidazole derivatives synthesized. Nitration, hydrogenation, and side chain reactions have been carried out.
- Zurabishvili,Lomidze,Samsoniya,Wesquet,Kazmaier
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experimental part
p. 941 - 949
(2009/05/26)
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- Synthesis and structure of Di[methoxy(ethoxy)carbonylamino-1H-benzimidazol- 5-yl] ethers
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A procedure was developed for preparing di[methoxy(ethoxy)carbonylamino-1H- benzimidazol-5-yl] ethers by the reaction of methyl or ethyl chloroformate with sodium cyanamide, followed by the reaction of the resulting methyl or ethyl cyanocarbamate with 4-(3,4-diaminophenoxy)-1,2-phenylenediamine in acidic solution. 2005 Pleiades Publishing, Inc.
- Pilyugin,Sapozhnikov,Kiseleva,Sapozhnikova,Vorob'eva,Klimakova
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p. 1509 - 1513
(2007/10/03)
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- Acyl derivatives of 2-aminobenzimidazole and their fungicide activity
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Procedures have been developed for the preparation of methyl 2-benzimidazolylcarbamate, 2-acetylaminobenzimidazole, 2- benzoylaminobenzimidazole, 2-(3,5-dibromo-2-hydroxybenzoylamino)benzimidazole, 1-(3,6-dichloro-2-methoxybenzoyl)-2-aminobenzimidazole, 2-(3,5-dichloro-2- hydroxybenzoylamino)benzimidazole, 2-(3,5-dichloro-2-methoxybenzoylamino) benzimidazole, and 1-(3,5,6-trichloro-2-methoxybenzoyl)-2-aminobenzimidazole. The synthesized compounds have been tested for fungicide activity.
- Pilyugin,Sapozhnikov,Sapozhnikova
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p. 738 - 743
(2007/10/03)
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- Method of production of 2-cyanoimino-1, 3-thiazolidine
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A method for producing high purity 2-cyanoimino-1,3-thiazolidine comprising the steps of: reacting an alkali metal cyanide compound, an alkali metal hydroxide, a lower alcohol and chlorine in an aqueous solution to form an carboimidic acid ester solution, then adding an organic solvent thereto, followed by adding a cyanamide solution to form an N-cyanocarbonimidic acid ester, and further extracting the resultant ester with an organic solvent extracting solution, followed by washing with an aqueous solution of a reducing agent solution to obtain a high purity, stable N-cyanocarbonimidic acid ester as a first step; and reacting the N-cyanocarbonimidic acid ester obtained in the first step with 2-aminoethanethiol to be cyclicized as a second step to thereby obtain a 2-cyanoimino-1,3-thiazolidine.
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- 2-Benzimidazolecarbamic acid esters by the cyanamide process
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A process for making 2-benzimidazolecarbamic acid, alkyl esters by reacting cyanamide or a cyanamide salt with an alkyl chloroformate in a weakly acidic to basic medium at a temperature between 0° and 105° C. to form an alkyl cyanocarbamate salt; then reacting the alkyl cyanocarbamate salt with an o-phenylenediamine in an acidic medium at a temperature between 40° and 130° C. to form the desired product and recovering it from the reaction mixture. The 2-benzimidazolecarbamic acid, alkyl esters are useful as fungicides and also useful as intermediates in the preparation of dialkyl esters of 2-carboxyaminobenzimidazole-1-carboxylic acids.
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