Otsuka Pharmaceutical Company, Limited

Norihiro Fukuyama

Michiaki Tominaga

Akihiro Yamamoto

Takao Nishi

Muneaki Kurimura

Shinji Aki

Junichi Minamikawa

Hisashi Miyamoto

Yoshihiko Okaichi

Yasuhiro Yamada

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. 

Process for producing carbostyril derivatives

The present invention provides a process for producing cilostazol [I] in a high yield and a high purity, by reacting a carbostyril derivative [II] with a tetrazole derivative [III] in the presence of an inorganic basic compound in a solvent of water, wherein water is used in an amount of 3 to 7-fold weight to that of the carbostyril derivative [II] and the inorganic basic compound is used in an amount of 1 to 6 mol per mol of the carbostyril derivative [II]. The process of the present invention is the improved and environment-friendly process for producing cilostazol being useful for pharmaceuticals

Process for production cilostazol

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.

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Tokushima, Japan

Norihiro Fukuyama