PURPOSE: To crystallize the title substance of high purity from a filtrate by dissolving the title substance in an org. solvent having a specific dielectric constant at b-.p. temp. to remove an insoluble substance and cooling the resulting soln. to filter off impurities before further cooling the soln.
CONSTITUTION: The title substance (dilazep dihydrochloride) is dissolved in an org. solvent having a dielectric constant of 20-40 (e.g.; 1-4C alkylnitrile, nitroalkane, 2-4C diol, nitrobenzene, benzonitrile) at 30°C or higher (pref., the b.p. temp. of the solvent) to be treated with activated carbon or diatomaceous earth and the treated soln. is filtered by a glass filter in order to remove a suspended substance. When the content of heavy metals in the crude product is high, the soln. is treated with complex forming EDTA and subsequently cooled to 25-30°C to remove impurities by repeating filtration. Subsequently, the soln. is cooled to 0-5°C to easily obtain high purity dilazep dihydrochloride having coronary blood vessel dilating action.
EMESHIYU CHIYUZUDEI
MERINDA GAARU
RAASUROO TSUORUNERU
EEBUA KOBUAACHIYU NEEE BOZOO
ERUZEEBETO MAGOO NEEE KARACHIY
GEEZA SHIRAAJII
RAYOSHIYU TORUDEI
PAARU BUAAGO
BUERONIKA PEETERU NEEE SEEKE
YOOZEFU RAITERU
GEEZA MATORUCHII
EEBUA FURUDEIGA
AGUNESHIYU HARUBAUERU NEEE NAJ
TEIBORU SABOO
