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AssigneeOtsuka Pharmaceutical Co., Ltd.
InventorsShinji Aki, Muneaki Kurimura, Takao Nishi, Junichi Minamikawa, Michiaki Tominaga, Norihiro Fukuyama, Akihiro Yamamoto
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The present invention provides a process for producing carbostyril derivatives (I) which are known to be useful as medical drug such as antithrombotic agent, cerebral circulation improver, anti-inflammatory agent, antiulcer agent, etc. in a high yield and a high purity. The carbostyril derivatives (I) can be produced by reacting a carbostyril derivative (II) with a tetrazole derivative (III) in the presence of a phase transfer catalyst. 1
A process for producing a carbostyril derivative represented by the following general formula (I):
A process for purifying cilostazol by recrystallization from a solvent selected from the group consisting of 1-butanol, acetone, toluene, methyl ethyl ketone, dichloromethane, ethyl acetate, methyl t-butyl ether, dimethyl acetamide-water mixtures, THF, methanol, isopropanol, benzyl alcohol, 2-pyrrolidone, acetonitrile, Cellosolve, monoglyme, isobutyl acetate, sec-butanol, tert-butanol, DMF, chloroform, diethyl ether and mixtures thereof.
Highly pure cilostazol free of impurities.
Micronized cilostazol of small particle size and narrow particle size distribution.
Cilostazol having an average particle size of less than 200 micrometer.
Cilostazol having an average particle size of less than 20 micrometer.
Dependencies are inferred from the claim text.