Patents by Inventor Yoshio Urawa

Yoshio Urawa 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: 5559236
    Abstract: The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1## The 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo-[4,5-b]pyridine derivative can be prepared in a high yield according to the present invention from a 2-amino-5-halogeno-3-nitropyridine derivative through amidation, N-alkylation and reductive cyclization. The halogen atom introduced at the 5-position as a protective group against nitration can be eliminated simultaneously in the step which is conducted thereafter. Thus, this process is industrially advantageous.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: September 24, 1996
    Assignees: Eisai Co., Ltd., Eisai Chemical Co., Ltd.
    Inventors: Yoshio Urawa, Ken Furukawa, Toshikazu Shimizu, Yoji Yamagishi, Tomio Tsurugi, Tomio Ichino
  • Patent number: 5557002
    Abstract: The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1## The 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative can be prepared in a high yield according to the present invention from a 2-amino-5-halogeno-3-nitropyridine derivative through amidation, N-alkylation and reductive cyclization. The halogen atom introduced at the 5-position as a protective group against nitration can be eliminated simultaneously in the step which is conducted thereafter. Thus, this process is industrially advantageous.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: September 17, 1996
    Assignees: Eisai Co., Ltd., Eisai Chemical Co., Ltd.
    Inventors: Yoshio Urawa, Ken Furukawa, Toshikazu Shimizu, Yoji Yamagishi, Tomio Tsurugi, Tomio Ichino
  • Patent number: 5554757
    Abstract: The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1## The 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo-[4,5-b]pyridine derivative can be prepared in a high yield according to the present invention from a 2-amino-5-halogeno-3-nitropyridine derivative through amidation, N-alkylation and reductive cyclization. The halogen atom introduced at the 5-position as a protective group against nitration can be eliminated simultaneously in the step which is conducted thereafter. Thus, this process is industrially advantageous.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: September 10, 1996
    Assignee: Eisai Co., Ltd.
    Inventors: Yoshio Urawa, Ken Furukawa, Toshikazu Shimizu, Yoji Yamagishi, Tomio Tsurugi, Tomio Ichino
  • Patent number: 5245060
    Abstract: A terpene derivative represented by the general formula (I): ##STR1## wherein R.sup.1 represents a lower alkyl group; R.sup.2 represents an alkyl group, a cycloalkyl group, a cycloalkylalkyl group, an aryl group, an arylalkyl group or a heteroaryl group; n is 0 or 1 or 2; and the symbol " " represents a single or double bond with the proviso that both of the linkages adjacent to each other are not simultaneously single bonds or double bonds which are useful for the preparation of drug, food, perfume and so on, and a process for preparing thereof.
    Type: Grant
    Filed: March 12, 1992
    Date of Patent: September 14, 1993
    Assignee: Eisai Co. Ltd.
    Inventors: Kimio Hamamura, Yoshio Urawa, Yukio Narabe, Yoshihiko Hisatake, Shizumasa Kijima