Preparation method for 3-amino-9, 13b-dihydro-1H-dibenz-[c, f]imidazo[1, 5-a]-azepine hydrochloride

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A method for preparing a 3-amino-9, 13b-dihydro-1H-dibenz-[c, f]imidazo[1, 5-a]-azepine hydrochloride(epinastine hydrochloride) is provided to improve purity and yield, shorten a reaction time by simplifying a process and improve the process to be environment-friendly. A method for preparing an epinastine hydrochloride represented by a formula(1) comprises the steps of : (a) after preparing cyanogen bromide in-situ, adding a methylene chloride solution where a compound represented by a formula(4) is dissolved to the cyanogen bromide to be subject to cyclization at a temperature of 0-20 deg.C for 1-24 hour(s); (b) after suspending an unrefined compound represented by a formula(2) and obtained from the step(a) in a mixture solution of water and an organic solvent, adding acid thereto to dissolve the suspension with adjusting a pH thereof; (c) after removing an organic layer from a resultant solution obtained from the step(b), adding activated carbon to an aqueous solution layer and agitating it with heating at a temperature of 10-60 deg.C; (d) adding an organic solvent and a base to the aqueous solution layer to adjust a pH thereof; (e) after concentrating an organic layer obtained from the step(d) under reduced pressure, adding a crystallization solvent thereto; (f) after cooling a solid crystallized by the step(e) and aging it to obtain a purified compound of the formula(2); (g) adding HCl to a suspension of the purified compound of the formula(2) and water to dissolve the suspension with adjusting a pH thereof; (h) seeding a hydrochloride of a small amount of the compound of the formula(2) with an aqueous solution of the pH-adjusted compound of the formula(2); and (i) after crystallizing the seeding solution through a first cooling and a second cooling, aging a generated solid. Further, an equivalent of the cyanogen bromide is 0.9 to 1.5.