3254-89-5Relevant articles and documents
Method for preparing high-purity difenidol hydrochloride
-
Paragraph 0032; 0036-0055; 0065-0076, (2019/12/25)
The invention discloses a method for preparing high-purity difenidol hydrochloride. The method comprises the following steps: after an intermediate alpha,alpha-diphenyl-1-piperidine butanol is prepared, dissolving the intermediate into one of acetone, ethyl acetate, tetrahydrofuran, butanone, acetonitrile and dichloromethane; increasing the temperature to 40-45 DEG C, adding activated carbon, andperforming uniform stirring for 0.5-1 hour; performing hot filtering, keeping the temperature of filtrate to 40-45 DEG C, dropping a hydrochloric acid solution at a speed of 2-8mL/minute till the pH value of the solution is 4-6, and continuously keeping the temperature to implement a reaction for 1-2 hours; reducing the temperature to 20-25 DEG C, keeping the temperature for 1-2 hours, further reducing the temperature to 5-10 DEG C, and performing stirring for 2-4 hours, so as to obtain difenidol hydrochloride through evolution. Not only is the preparation method disclosed by the invention simple, low in instrument and equipment requirement and low in production cost, but also the prepared target product has a small number of impurity types and has a low content of impurities, the salt formation mole yield of the product is 90% or greater, the purity is 99.8% or greater, an impurity diphenyl methanol is controlled within 0.05% or less, meanwhile, the content of alkene impurities is controlled within 0.05% or less, and the content of total impurities is 0.1% or less.