A METHOD FOR PRODUCING HYDROCHLORIDE 5-ETHOXY-2-ETHYLTHIOBENZYMIDAZOLE OF PHARMACOPEIA PURITY

摘要

The method for producing hydrochloride 5-ethoxy-2-ethylthiobenzymidazole of pharmacopeia purity comprises condensation of 4-ethoxy-1,2-phenylenediamine with potassium ethylxantogenate at elevated temperature with subsequent alkylation of the obtained 5-ethoxy- 2-mercaptobenzimidazole with ethyl bromide to hydrobromide of 5-ethoxy-2-ethylthiobenzimidazole, transition thereof to the base under the action of alkali, treatment of the base with sulphuric acid with formation of hydrochloride of 5-ethoxy-2-ethylthiobenzimiazole with subsequent purification thereof by crystallization from diluted sulhuric acid in the presence of activated coal. The substance of 4-ethoxy-1-nitro-2-aminobenzol is reduced by hydrogen on Reney nickel to 4-ethoxy-1,2-phenylenediamine. By cyclization of diamine with potassium ethylxantogenate 5-ethoxy-2-mercaptobenzimidazole is obtained, which alkylation leads to formation of hydrobromide 5-ethoxy-2-ethylthiobenzimidazole, and it is transformed in hydrochloride through intermediary producing the baseof 5-ethoxy-2-ethylthiobenzimidazole by action on the latter with sulphuric acid.