- Preparation method of 4-propythio-2-nitroaniline
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The invention discloses a preparation method of 4-propythio-2-nitroaniline, and solves the technical problems of unreasonable preparation method, high raw material price, high toxicity, complex operation, high cost, large production of three wastes, low yield and unsuitability for industrial production in the prior art. The preparation method of 4-propythio-2-nitroaniline provided by the inventiontakes o-nitroaniline, disulfur dichloride and chloropropane as the raw materials, and carries out condensation reaction and alkylation reaction in order under the action of a catalyst so as to obtain4-propythio-2-nitroaniline. The method can be widely applied technical field of synthesis of albendazole.
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Paragraph 0026-0065; 0074; 0075
(2019/12/08)
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- Albendazole synthesis method
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The invention discloses an albendazole synthesis method. The albendazole synthesis method includes reacting ammonium thiocyanate with chlorine gas in a lower alcohol solvent to obtain chlorothiocyanate, reacting ortho-nitroaniline with the chlorothiocyanate in the lower alcohol solvent to obtain 4-thiocyano-2-nitroaniline, reacting the 4-thiocyano-2-nitroaniline with a sodium hydroxide solution toobtain 4-sodium sulfonate-2-nitroaniline, performing hydrochloric acid acidification to obtain 4-mercapto-2-nitroaniline, subjecting the 4-mercapto-2-nitroaniline and propylene to Markovnikov addition reaction to obtain 4-propylthio-2-nitroaniline, and reacting 4-propylthio-o-phenylenediamine with methylcyanocarbamate to obtain albendazole. The albendazole synthesis method has the advantages thata novel synthetic route is applied to prepare the albendazole, the defects of high impurity quantity and low yield in the current production process are overcome, the chlorothiocyanate is prepared toserve as an intermediate and then reacts with the ortho-nitroaniline, and impurities can be avoided effectively; the propylene is introduced for the addition reaction, raw materials are clean and free from pollution, introduction of highly toxic sodium cyanide is avoided, the total yield is high, and the albendazole synthesis method has a good industrialization prospect.
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Paragraph 0055-0064
(2019/03/25)
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- A preparing method of albendazole
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A preparing method of albendazole is disclosed. The method adopts 2-nitro-4-thiocyanatoaniline as a raw material, and includes salifying with an aqueous sodium hydroxide solution in an n-propanol solvent under nitrogen protection, reacting with bromopropane, and separating to obtain an n-propanol solution of 2-nitro-4-(propylthio)aniline, and therefore a problem that an impurity that is methyl 5-(methylthio)benzoimidazol-2-yl carbamate in products is high in content because steps of salifying in methanol with sodium sulfide and then reacting with bromopropane in processes at present is overcome. A technique of reducing the 2-nitro-4-(propylthio)aniline by utilizing hydrazine hydrate is adopted to replace a technique of reducing with sodium sulfide at present, thus overcoming a problem that sulfur-containing waste water is high in amount and difficult to treat in the sodium sulfide reduction technique. A methanol solution of methyl O-methyl isourea formate is adopted as a ring closing agent, thus overcoming a problem that waste water is high in amount in processes at present when cyanamide and an aqueous methyl formate solution are adopted as ring closing agents. The method is advantaged by a small waste water amount, capability of being environmental friendly, high product purity, and the like.
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Paragraph 0040; 0041; 0042
(2016/10/31)
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- PROCESS FOR PREPARATION OF ALBENDAZOLE
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The present invention discloses a novel, cost-effective process for preparation of a benzimidazole carbamates compound. Specifically, it relates to the process for the preparation of anti-parasite bulk drug albendazole. The process comprises a) thiocyanating 2-nitroaniline of formula VI with ammonium thiocyanated in presence of a halogen to obtain 2-nitro-4-thiocyanoaniline of formula V; b)propylating 2-nitro-4-thiocyanoaniline of formula V with propylbromide in presence of n-propanol and a base in absence of a phase transfer catalyst to obtain 4-propylthio-2-nitroaniline of formula III; C) reducing the nitro group of 4-propylthio-2-nitroaniline prepared in step b) by reacting an aqueous alkali metal sulphide or an alkaline metal sulphide to obtain 4-propylthio-o-phenylenediamine of formula II; and d)condensing 4-propylthio-o-phenylenediamine of formula II with alkali or alkaline earth metal salt of methylcyano carbamate in presence of an acid to form Albendazole of formula I.
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Paragraph 0022
(2013/11/19)
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- A PROCESS FOR PREPARATION OF ALBENDAZOLE
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The present invention discloses a novel, cost-effective process for preparation of a benzimidazole carbamates compound. Specifically, it relates to the process for the preparation of anti-parasite bulk drug albendazole. The process comprises a) thiocyanating 2-nitroaniline of formula VI with ammonium thiocyanated in presence of a halogen to obtain 2-nitro-4-thiocyanoaniline of formula V; b)propylating 2-nitro-4-thiocyanoaniline of formula V with propylbromide in presence of n-propanol and a base in absence of a phase transfer catalyst to obtain 4-propylthio-2-nitroaniline of formula III; C) reducing the nitro group of 4- propylthio-2-nitroaniline prepared in step b) by reacting an aqueous alkali metal sulphide or an alkaline metal sulphide to obtain 4-propylthio-o-phenylenediamine of formula II; and d)condensing 4-propylthio-o-phenylenediamine of formula II with alkali or alkaline earth metal salt of methylcyano carbamate in presence of an acid to form Albendazole of formula I.
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Page/Page column 5
(2012/06/15)
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- Preparation of N-methoxycarbonyl-N'-[2-nitro-4(5)-propyl-thiophenyl]thiourea as prodrugs of albendazole
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N-methoxycarbonyl-N'-(2-nitro-4-propylthiophenyl)thiourea and N-methoxycarbonyl-N'-(2-nitro-5-propylthiophenyl)thiourea, prodrugs of albendazole, have been synthesized. The biotransformation in rats, after oral administration of these prodrugs to albendazole and albendazole sulphoxide, is described.
- Hernandez-Luis, Francisco,Castillo, Rafael,Yepez-Mulia, Lilian,Cedillo-Rivera, Roberto,Martinez-Vazquez, Gabriel,Morales-Hurtado, Raul,Jung, Helgi,Sanchez, Monica,Hernandez-Campos, Alicia,Viveros, Noemi,Munoz, Onofre
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p. 2231 - 2236
(2007/10/03)
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- Process for the preparation of 2-benzimidazole carbamates
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A process for preparing 2-benzimidazole carbamate compounds by condensing an alkyl cyano carbamate with an o-phenylenediamine produced by reacting an ortho-nitro-aniline with thiocyanogen followed by replacement of the cyanide with an alkyl group and then converting the nitro group to the amine.
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- Method of treating helminthiasis by parenteral or topical administration of sulfoxide derivatives of benzimidazoles
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A method is provided for treating or inhibiting helminthiasis by parenterally or topically administering sulfoxide derivatives of benzimidazoles having the structure STR1 wherein R1 is lower alkyl or phenyl-lower alkyl, and R2 is lower alkyl. Pharmaceutical compositions for use in the above method are also provided.
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