Patent ID: 7829726

Claim:
A method for manufacturing sertaconazole mononitrate (I) which comprises: (i) the reaction of 1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)-ethanol (II) with 3-bromomethyl-7-chlorobenzo [b] thiophene (III) in the presence of tetrabutylammonium hydrogen sulfate (IV, Z═HSO 4 ) and sodium hydroxide in toluene at 30-45° C., followed by addition of water, cooling the mixture to a mass temperature of 0-15° C. and then filtering, washing the solid material obtained with water and toluene, and refluxing the sertaconazole free base thus obtained in absolute ethanol until complete dissolution, heating the mass at 60-80° C. and adding water, further cooling at 5-15° C., filtering the solid material formed and washing with a mixture of ethanol and water, re-dissolving the obtained pure sertaconazole free base in absolute ethanol at 70-80° C., cooling the mixture at a mass temperature of 65-75° C. and thereafter adding a solution containing 60% nitric acid in water, maintaining the temperature for 10-20 minutes, keeping the pH below 2, cooling the mixture at 5-15° C. and maintaining this temperature during 30 minutes to 2 hours, followed by filtering and washing to yield sertaconazole mononitrate monohydrate (V); and (ii) dissolving sertaconazole mononitrate monohydrate in a mixture of ethanol and water, heating the mass at 75-80° C., adding the mixture over an aqueous solution of nitric acid cooled at 5-15° C., filtering, drying at 60-70° C., sieving and finally drying at 80-90° C.