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ChemicalBook CAS DataBase List Albendazole
54965-21-8

Albendazole synthesis

10synthesis methods
Albendazole, methyl-[5-(propylthio)-1H-benzoimidazol-2-yl]carbamate (38.1.18), is also made by the heterocyclization of a derivative of phenylenediamine to a derivative of benzimidazole. In order to do that, 3-chloro-6-nitroacetanylide is reacted with propylmercaptane to make 3-propylthio-6-nitroacetanylide (38.1.6). Reducing the nitro group in this compound with hydrogen using a palladium on carbon catalyst gives 4-(propylthio)-o-phenylenediamine (38.1.7). Reacting the resulting derivative of o-phenylenediamine with cyanamide and then with the methyl chloroformate gives the desired albendazole.

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Yield:54965-21-8 520 kg

Reaction Conditions:

with hydrogenchloride in water;acetone at 85;Large scale;

Steps:

1.f (f) Preparation of Albendazole

(f)
Preparation of Albendazole
4-Propylthio-o-phenylenediamine (400 kg) was treated with acetone (400 L).
Then water (380 L) and conc. HCl (360 kg) was added to it.
Exothermic reaction observed upto 48° C.
Reaction mass was cooled to room temperature and methyl-N-Cyano Carbamate was added.
The reaction mass was heated to 80-85° C.
The pH was adjusted to 4-4.5 by concentrated HCl and centrifuged.
The material and washed with hot water, tap water, methanol and finally with acetone.
Weight: 500-520 kg.

References:

US2013/303782,2013,A1 Location in patent:Paragraph 0031

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