68828-69-3Relevant articles and documents
Synthesis method of triclabendazole
-
Paragraph 0025; 0026; 0029; 0030, (2019/01/13)
The invention discloses a synthesis method of triclabendazole, comprising the following steps: reducing 4-chloro-5-(2,3-dichlorophenoxy)-2-nitroaniline as a raw material in an organic solvent by trichlorosilane, thus obtaining an intermediate compound; directly making ring closing reaction with carbon disulfide in the presence of potassium hydroxide, thus preparing an intermediate; enabling the intermediate and dimethyl carbonate to make methylation reaction under DBU catalysis, thus finally preparing triclabendazole. Through the process, a nitro reduction method is improved, the requirementsfor equipment are reduced, and post-treatment steps are simplified; by combining the nitro reduction and the cyclization into a one-step reaction, the operation procedure is simplified and the yield is increased; by changing a feeding sequence in the process of cyclization, the release rate of hydrogen sulfide is controlled, and the influence on environment is reduced. Replacing dimethyl sulfate or methyl iodide with dimethyl carbonate for methylation is more environmentally friendly; the obtained triclabendazole meets the European Pharmacopeas Standards in terms of all indicators, the total yield can reach 55-60%, indicating an obviously improved process and a promising prospect in industrial application.
PROCESS FOR PREPARATION OF TRICLABENDAZOLE
-
, (2013/11/19)
The present invention discloses a method for preparing Triclabendazole comprising condensing N-(4,5-dichloro-2-ni-trophenyl)acetamide with 2,3-dichlorophenol to obtain 4-chloro-5(2,3-dichlorophenoxy)-2-nitrophenyl acetamide and it to obtain 4-chloro-5(2,3-dichlorophenoxy)-2-nitroaniline; reducing 4-chloro-5(2,3-dichlorophenoxy)-2-nitroaniline in presence of Raney nickel to obtain 4-chloro-5-(2,3-dichlorophenoxy)benzene-1,2-diamine of; cyclising 4-chloro-5-(2,3-dichlorophenoxy)benzene-1,2-diamine in presence of carbondisulfide to obtain 6-chloro-5-(2,3-dichlorophenoxy)-1H-benzimidazole-2-thiol; methylating 6-chloro-5-(2,3-dichlorophenoxy)-1H-benzimidazole-2-thiol using a methylating agent to obtain triclabendazole methanesulfonate salt; converting triclabendazole methanesulfonate salt to hydrochloride salt of Triclabendazole and hydrolysing it to obtain Triclabendazole.
2H-Benzimidazoles (Isobenzimidazoles). Part 7. A New Route to Triclabendazole and Congeneric Benzimidazoles
Iddon, Brian,Kutschy, Peter,Robinson, Andrew G.,Suschitzky, Hans,Kramer, Walter,Neugebauer, Franz A.
, p. 3129 - 3134 (2007/10/02)
A new synthesis of the selective anthelmintic agent triclabendazole 7 from the readily available 5,6-dichloro-2H-benzimidazole-2-spirocyclohexane 2 by simple steps is described.Analogous benzimidazoles difficult to prepare by conventional methods are similarly obtained.Triclabendazole can exist as a low-melting metastable solid (m.p. 85-90 deg C) convertible by heating or recrystallisation from ethanol into its stable form (m.p. 176-178 deg C).