Patents by Inventor Hiroshi Okumoto

Hiroshi Okumoto 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: 6410757
    Abstract: The object of the invention is to develop baccatin derivatives useful for preparing taxoid compounds such as paclitaxel and a process for the producing the same. The invention provides baccatin derivatives represented by the general formula (I) as well as a process for producing baccatin derivatives represented by the general formula (I) above, which comprises allowing a baccatin represented by the general formula (II) to react with a &bgr;-ketoester in the absence of a catalyst or in the presence of a tin compound or an amine base, preferably under reduced pressure.
    Type: Grant
    Filed: February 7, 2000
    Date of Patent: June 25, 2002
    Assignees: Bio Research Corporation of Yokohama, Ensuiko Sugar Refining Co. Ltd.
    Inventors: Tadakatsu Mandai, Hiroshi Okumoto, Katsuyoshi Nakanishi, Koji Hara, Katsuhiko Mikuni, Kozo Hara
  • Patent number: 6306893
    Abstract: An object of the invention is to develop galactose or mannose derivatives of docetaxel, etc. having improved solubility and physiological activity, to alleviate burden imposed on patients and to provide effective therapeutic drug for tumors. The present invention provides taxoid derivatives comprising any of paclitaxel, docetaxel and 10-deacetyl-baccatin III to which galactose or mannose is linked through a spacer, and methods for producing taxoid derivatives comprising reacting paclitaxel, docetaxel or 10-deacetyl-baccatin III with tetrabenzyl acetyloxygalactoside or tetrabenzyl acetyloxymannoside, subjecting the product to debenzylation reaction, and optionally to detriethylsilylation reaction.
    Type: Grant
    Filed: April 7, 2000
    Date of Patent: October 23, 2001
    Assignees: Ensuiko Sugar Refining Company, Ltd, Bio Research Corporation of Yokohama, Kaken Pharmaceutical Company, Ltd.
    Inventors: Tadakatsu Mandai, Hiroshi Okumoto, Koji Hara, Katsuhiko Mikuni, Kozo Hara, Yoshinori Tsuchiya, Kosho Nakamura, Teruhiko Umetsu
  • Patent number: 6136990
    Abstract: A taxoid compound represented by general formula (I) ##STR1## where the symbols R.sup.1, R.sup.2, R.sup.3, R.sup.4, Bz, and Ac have specified meanings. Also, a method for producing the taxoid derivative from a baccatin derivative having a .beta.-ketoester group at the 13-position by transesterification and a method for producing taxoid compound such as paclitaxel from the taxoid derivative under mild condition are disclosed.
    Type: Grant
    Filed: February 15, 2000
    Date of Patent: October 24, 2000
    Assignees: Bio Research Corporation of Yokohama, Ensuiko Sugar Refining Co., Ltd., Tadakatsu Mandai
    Inventors: Tadakatsu Mandai, Hiroshi Okumoto, Katsuyoshi Nakanishi, Koji Hara, Katsuhiko Mikuni, Kozo Hara
  • Patent number: 6075132
    Abstract: Disclosed are ursodeoxycholic acid derivatives having an increased solubility in water, and methods for producing the derivatives. To produce the derivatives, ursodeoxycholic acid is protected at its carboxyl group with a benzyl group, then reacted with tetrabenzyl-acetic acid-oxyglucoside of the following formula (1), and de-benzylated; or ursodeoxycholic acid is protected at its hydroxyl group with a t-butyldimethylsilyl group, then reacted with tetrabenzyl-2-hydroxyethyloxyglucoside of the following formula (2), and de-t-butyldimethylsilylated and de-benzylated.
    Type: Grant
    Filed: April 30, 1998
    Date of Patent: June 13, 2000
    Assignees: Bio Research Corporation of Yokohama, Ensuiko Sugar Refining Co., Ltd., Kaken Pharmaceutical Co., Ltd.
    Inventors: Tadakatsu Mandai, Hiroshi Okumoto, Katsuyoshi Nakanishi, Koji Hara, Katsuhiko Mikuni, Kozo Hara, Teruhiko Umetsu
  • Patent number: 5854408
    Abstract: A sugar derivative wherein a hydroxy-carboxylic acid is combined to a position 1 of a sugar via ether linkage, and other hydroxyl groups are protected with a protective groups. A method of producing the sugar derivative, comprises allowing glycolic ester to react with a compound so as to combine said glycolic ester at the position 1 of the sugar skeleton, and then saponifying, said compound has on the position 1 any of hydroxyl group, halogen atom and sulfur atom with a substitutent group, and has other hydroxyl groups being protected with a protective groups.
    Type: Grant
    Filed: June 3, 1997
    Date of Patent: December 29, 1998
    Assignees: Ensuiko Sugar Refining Co., Ltd., Tadakatsu Mandai
    Inventors: Tadakatsu Mandai, Hiroshi Okumoto, Koji Hara, Katsuhiko Mikuni, Kozo Hara, Hiroki Hamada
  • Patent number: 5767297
    Abstract: A taxoid derivative wherein sugar is combined with any one of paclitaxel, docetaxel and 10-deacetyl-bacatin III via a spacer. A method of producing the taxoid derivative comprises protecting hydroxyl groups at specific position of paclitaxel or docetaxel by protective compound followed by reacting with tetrabenzyl acetyloxyglucoside, and then carrying out debenzyl and detriethylsilyl reactions. A method of producing the taxoid derivative comprises reacting paclitaxel or docetaxel with tetrabenzyl acetyloxyglucoside, and then carrying out debenzyl reaction.
    Type: Grant
    Filed: June 3, 1997
    Date of Patent: June 16, 1998
    Assignees: Ensuiko Sugar Refining Co., Ltd., Tadakatsu MANDAI, Kaken Pharmaceutical Co., Ltd.
    Inventors: Tadakatsu Mandai, Hiroshi Okumoto, Koji Hara, Katsuhiko Mikuni, Kozo Hara, Hiroki Hamada