Patents by Inventor Keizo Takayanagi

Keizo Takayanagi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6545024
    Abstract: The present invention provides acetone complexes of sulfoxide compounds, useful as medicines such as inhibitors of gastric acid secretion and anti-ulcer agents or as intermediates for production of medicines, a process for producing the same and a purification method of using the same. Namely, it is the acetone complexes of sulfoxide compounds or of pharmaceutically acceptable salts thereof represented by the following formula: (wherein R1 represents a hydrogen atom, a methoxy group or a difluoromethoxy group, R2 represents a methyl group or a methoxy group, R3 represents a 3-methoxypropoxy group, a methoxy group or a 2,2,2-trifluoroethoxy group, R4represents a hydrogen atom or a methyl group, n and m independently represent an integer of 1 to 4, and B represents a hydrogen atom, an alkali metal atom or ½ alkaline earth metal atom), which are obtained by treating the sulfoxide compounds or pharmaceutically acceptable salts thereof with acetone.
    Type: Grant
    Filed: October 17, 2000
    Date of Patent: April 8, 2003
    Assignee: Eisai Co., Ltd.
    Inventors: Masahiko Tsujii, Nobuo Niikawa, Keizo Takayanagi, Shigeharu Nochi
  • Patent number: 6180652
    Abstract: The present invention provides acetone complexes of sulfoxide compounds, useful as medicines such as inhibitors of gastric acid secretion and anti-ulcer agents or as intermediates for production of medicines, a process for producing the same and a purification method of using the same. Namely, it is the acetone complexes of sulfoxide compounds or of pharmaceutically acceptable salts thereof represented by the following formula: (wherein R1 represents a hydrogen atom, a methoxy group or a difluoromethoxy group, R2 represents a methyl group or a methoxy group, R3 represents a 3-methoxypropoxy group, a methoxy group or a 2,2,2-trifluoroethoxy group, R4 represents a hydrogen atom or a methyl group, n and m independently represent an integer of 1 to 4, and B represents a hydrogen atom, an alkali metal atom or ½ alkaline earth metal atom), which are obtained by treating the sulfoxide compounds or pharmaceutically acceptable salts thereof with acetone.
    Type: Grant
    Filed: November 3, 1999
    Date of Patent: January 30, 2001
    Assignee: Eisai Co., Ltd.
    Inventors: Masahiko Tsujii, Nobuo Niikawa, Keizo Takayanagi, Shigeharu Nochi
  • Patent number: 4721788
    Abstract: A novel 4-cyanopiperidine derivative, which is represented by the following general formula (I): ##STR1## wherein X means a halogen atom, or an acid addition salt thereof, is prepared by reacting N-(2-hydroxyethyl)-4-carbamoylpiperidine or an acid addition salt thereof with a dehydrating and halogenating agent; or by reacting 4-cyanopiperidine or a salt thereof with a compound represented by the following general formula (IV):X--CH.sub.2 CH.sub.2 --Y (IV)wherein X has the same meaning as defined above and Y denotes the same halogen atom as X or another halogen atom. The derivative is useful as intermediate for synthesis of quinuclidine derivative which is in turn useful as intermediate for the production of medicines, chemicals, etc.
    Type: Grant
    Filed: July 8, 1986
    Date of Patent: January 26, 1988
    Assignee: Eisai Co., Ltd.
    Inventors: Hiroshi Yamauchi, Seiichiro Nomoto, Isao Sugiyama, Yuuki Komatu, Takeo Kanai, Keizo Takayanagi, Yasuhide Tanaka, Atsushi Koiwa, Shinichi Endoh
  • Patent number: 4433142
    Abstract: Improved process for the preparation of 7-(2-amino-2-phenyl-acetamido)cephem derivatives of the general formula (I): ##STR1## wherein R.sub.1 is a hydrogwn atom or hydroxyl group, n stands for 0, 1 or 2, and A denotes a nitrogen-containing heterocyclic group or a direct bond coupling directly the sulfur atom and the --(CH.sub.2).sub.n COOH group together, as well as pharmaceutically acceptable salts thereof. The process is not only simple and easy to carry out, but also provides as crystalline precipitate the intended products with a high yield. The 7-(2-amino-2-phenyl-acetamido)cephem derivatives are useful as intermediates for syntheses of antibacterial agents.
    Type: Grant
    Filed: May 7, 1982
    Date of Patent: February 21, 1984
    Assignee: Eisai Co., Ltd.
    Inventors: Keizo Takayanagi, Yasuhide Tanaka, Tasuke Kawabata, Fujio Nakamura, Yukio Morita, Shigeto Negi, Takeo Kanai, Eiichi Morita
  • Patent number: 4163864
    Abstract: 2-METHYL-3-PRENYL-4,5,6-TRIMETHOXYPHENOL OF THE FORMULA: ##STR1## wherein R represents a group of the formula: ##STR2## WHEREIN N IS AN INTEGER OF 0 TO 9 AND A and B represent hydrogen atom or A--B may form a bond,Is prepared by reacting 6-methyl-2,3,4-trimethoxyphenol with a prenol or isoprenol substituted by the group R as defined above in the presence of a complex catalyst comprising Lewis acid and a silica-alumina compound.
    Type: Grant
    Filed: February 16, 1978
    Date of Patent: August 7, 1979
    Assignee: Eisai Co., Ltd.
    Inventors: Eiichi Morita, Hirosaburo Ejiri, Keizo Takayanagi, Yukio Morita, Yasuhide Tanaka, Shizumasa Kijima, Kimio Hamamura, Isao Yamatsu