Patents Assigned to Eisai Chemical
  • Patent number: 5998611
    Abstract: An industrially excellent, novel process for producing cephem compounds which are useful as medicines, particularly, antibiotics and represented by the following formula (III): ##STR1## wherein R.sup.1 means either group represented by the following formula: ##STR2## R.sup.2 denotes a carboxyl group or a carboxyl anion, and R.sup.3 stands for a lower alkyl group, a halogen atom, a lower alkyl group substituted by an aliphatic acyloxy group having 1-6 carbon atoms, or any one of the groups represented by the following formulae: ##STR3## which comprises reacting in water a 3-cephem-4-carboxylate represented by the following formula (I): ##STR4## or a salt thereof with an acid chloride represented by the formula (II), R.sup.1 COCl.
    Type: Grant
    Filed: September 25, 1997
    Date of Patent: December 7, 1999
    Assignee: Eisai Chemical Co., Ltd.
    Inventors: Homare Shinohara, Masato Kodama, Kimio Hamamura, Hirofumi Kuroda
  • Patent number: 5874611
    Abstract: A hydroquinone derivative (I) represented by the following formula: ##STR1## wherein R.sup.1 is a hydrogen atom, acetyl group or benzoyl group, such hydroquinone derivative being useful as an intermediate for chroman derivatives useful as a blood sugar-lowering agent.
    Type: Grant
    Filed: July 1, 1996
    Date of Patent: February 23, 1999
    Assignee: Eisai Chemical Co., Ltd.
    Inventors: Kimio Hamamura, Chiaki Seki, Masayuki Konishi
  • Patent number: 5700938
    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: December 23, 1997
    Assignees: Eisai Co., Ltd., Eisai Chemical Co., Ltd.
    Inventors: Yoshio Urawa, Ken Furukawa, Toshikazu Shimizu, Yoji Yamagishi, Tomio Tsurugi, Tomio Ichino
  • Patent number: 5686635
    Abstract: Disclosed herein are a quinone derivative represented by the following formula: ##STR1## wherein R.sup.1 and R.sup.2 are identical with or different from each other and mean individually a lower alkyl or lower alkoxy group, or may form an aromatic ring together, R.sup.3 denotes a lower alkyl group, n stands for 0 or an integer of 1-9, and a linkage --- is a single or double bond, such as a vitamin K derivative or coenzyme derivative; and a process for the preparation of the quinone derivative at a high yield without forming any geometric isomer; as well as a 1,4,4.sub.a,8.sub.a -tetrahydro-4.sub.a .alpha.-alkenyl-1.alpha.,4.alpha.-methanonaphthalene-5,8-dione derivative which is useful as an intermediate for the preparation of the quinone derivative.
    Type: Grant
    Filed: July 26, 1996
    Date of Patent: November 11, 1997
    Assignee: Eisai Chemical Co., Ltd.
    Inventors: Kimio Hamamura, Tetsuo Iwama, Chiaki Seki, Masayuki Konishi
  • Patent number: 5677471
    Abstract: Disclosed herein are a quinone derivative represented by the following formula: ##STR1## wherein R.sup.1 and R.sup.2 are identical with or different from each other and mean individually a lower alkyl or lower alkoxy group, or may form an aromatic ring together, R.sup.3 denotes a lower alkyl group, n stands for 0 or an integer of 1-9, and a linkage--is a single or double bond, such as a vitamin K derivative or coenzyme Q derivative; and a process for the preparation of the quinone derivative at a high yield without forming any geometric isomer; as well as a 1,4,4.sub.a,8.sub.a -tetrahydro-4.sub.a .alpha.-alkenyl-1.alpha.,4.alpha.-methanonaphthalene-5,8-dione derivative which is useful as an intermediate for the preparation of the quinone derivative.
    Type: Grant
    Filed: July 26, 1996
    Date of Patent: October 14, 1997
    Assignee: Eisai Chemical Co., Ltd.
    Inventors: Kimio Hamamura, Tetsuo Iwama, Chiaki Seki, Masayuki Konishi
  • Patent number: 5665888
    Abstract: Described is a protected aminothiazolylacetic acid derivative represented by the following formula (I): ##STR1## wherein A represents a nitrogen atom or a methine group, R.sup.1 and R.sup.2 may be the same or different and individually represent a hydrogen atom, a lower alkyl group or a substituted or unsubstituted aryl group, R.sup.3 represents a lower alkoxy group, a halogenated lower alkoxy group, a triphenylmethoxy group, a lower alkyl group or an acyloxy group, and R.sup.4 represents a halogen atom, a hydroxy group, a lower alkoxy group or a substituted or unsubstituted amino group; and salts thereof; as well as processes for the preparation thereof. The protected aminothaizolylacetic acid derivative according to the present invention is an useful intermediate for introducing a 2-(2-aminothiazol-4-yl)-2-alkoxyiminoacetyl group or a 2-(2-aminotiazol-4-yl)-2-alkenoyl group into a cephem skeleton.
    Type: Grant
    Filed: March 28, 1995
    Date of Patent: September 9, 1997
    Assignee: Eisai Chemical Co., Ltd.
    Inventors: Yoshio Urawa, Akihiko Shimotani, Takeo Kanai, Masahiko Tsujii
  • Patent number: 5650518
    Abstract: Described is a protected aminothiazolylacetic acid derivative represented by the following formula (I): ##STR1## wherein A represents a nitrogen atom or a methine group, R.sup.1 and R.sup.2 may be the same or different and individually represent a hydrogen atom, a lower alkyl group or a substituted or unsubstituted aryl group, R.sup.3 represents a lower alkoxy group, a halogenated lower alkoxy group, a triphenylmethoxy group, a lower alkyl group or an acyloxy group, and R.sup.4 represents a halogen atom, a hydroxy group, a lower alkoxy group or a substituted or unsubstituted amino group; and salts thereof; as well as processes for the preparation thereof. The protected aminothaizolylacetic acid derivative according to the present invention is an useful intermediate for introducing a 2-(2-aminothiazol-4-yl)-2-alkoxyiminoacetyl group or a 2-(2-aminotiazol-4-yl)-2-alkenoyl group into a cephem skeleton.
    Type: Grant
    Filed: January 25, 1996
    Date of Patent: July 22, 1997
    Assignee: Eisai Chemical Co., Ltd.
    Inventors: Yoshio Urawa, Akihiko Shimotani, Takeo Kanai, Masahiko Tsujii
  • Patent number: 5637716
    Abstract: Intermediates for the preparation of benzothiazole derivatives useful for the prevention and treatment of diseases for which an inhibitory action against the production of leukotriene and thromboxane is efficacious, and industrially advantageous processes for the preparation of the intermediates.
    Type: Grant
    Filed: December 27, 1995
    Date of Patent: June 10, 1997
    Assignees: Eisai Co., Ltd., Eisai Chemical Co., Ltd.
    Inventors: Yuuki Komatsu, Norio Minami, Ken Furukawa, Hiroshi Nishimura, Yoji Yamagishi
  • Patent number: 5631378
    Abstract: Described is a protected aminothiazolylacetic acid derivative represented by the following formula (I): ##STR1## wherein A represents a nitrogen atom or a methine group, R.sup.1 and R.sup.2 may be the same or different and individually represent a hydrogen atom, a lower alkyl group or a substituted or unsubstituted aryl group, R.sup.3 represents a lower alkoxy group, a halogenated lower alkoxy group, a triphenylmethoxy group, a lower alkyl group or an acyloxy group, and R.sup.4 represents a halogen atom, a hydroxy group, a lower alkoxy group or a substituted or unsubstituted amino group; and salts thereof; as well as processes for the preparation thereof. The protected aminothaizolylacetic acid derivative according to the present invention is an useful intermediate for introducing a 2-(2-aminothiazol-4-yl)-2-alkoxyiminoacetyl group or a 2-(2-aminotiazol-4-yl)-2-alkenoyl group into a cephem skeleton.
    Type: Grant
    Filed: January 25, 1996
    Date of Patent: May 20, 1997
    Assignee: Eisai Chemical Co., Ltd.
    Inventors: Yoshio Urawa, Akihiko Shimotani, Takeo Kanai, Masahiko Tsujii
  • Patent number: 5618969
    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##
    Type: Grant
    Filed: October 19, 1995
    Date of Patent: April 8, 1997
    Assignees: Eisai Co., Ltd., Eisai Chemical
    Inventors: Yoshio Urawa, Ken Furukawa, Toshikazu Shimizu, Yoji Yamagishi, Tomio Tsurugi, Tomio Ichino
  • Patent number: 5608092
    Abstract: The present invention relates to intermediates useful for the preparation of vitamin K derivatives.
    Type: Grant
    Filed: January 5, 1995
    Date of Patent: March 4, 1997
    Assignee: Eisai Chemical Co., Ltd.
    Inventors: Kimio Hamamura, Chiaki Seki, Masayuki Konishi
  • Patent number: 5608068
    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: March 4, 1997
    Assignees: Eisai Co., Ltd., Eisai Chemical Co., Ltd.
    Inventors: Yoshio Urawa, Ken Furukawa, Toshikazu Shimizu, Yoji Yamagishi, Tomio Tsurugi, Tomio Ichino
  • Patent number: 5587504
    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.
    Type: Grant
    Filed: October 19, 1995
    Date of Patent: December 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: 5565586
    Abstract: A process for the industrial preparation of the quinone derivative represented by the following general formula: ##STR1## which is an intermediate for chroman derivatives useful as a blood sugar lowering agent, and novel intermediates, encompasses the following:(1) Oxidation of the corresponding hydroquinone derivative, and(2) Hydrolysis of the corresponding acyl hydroquinone derivative with a Claisen alkali, followed by the oxidation of resulting hydrolyzate.
    Type: Grant
    Filed: March 1, 1995
    Date of Patent: October 15, 1996
    Assignee: Eisai Chemical Co., Ltd.
    Inventors: Kimio Hamamura, Chiaki Seki, Masayuki Konishi
  • 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: 5547580
    Abstract: Disclosed herein is a purification method of a crude product by column chromatography on silica gel or on a vinyl alcohol copolymer. Methanol-containing n-hexane and/or n-hexane-containing methanol is used as an eluent to elute the crude product, thereby obtaining an intended product with high purity and good yield. The solvents recovered from the effluent can be regenerated without any trouble such as rectification and a great cost by mixing them under stirring and then separating the resulting upper and lower layer from each other. The column used can also be reused again and again by washing with methanol. The separation and purification method is excellent in separation efficiency, operation efficiency and economical efficiency.
    Type: Grant
    Filed: March 22, 1995
    Date of Patent: August 20, 1996
    Assignee: Eisai Chemical Co., Ltd.
    Inventors: Masahiko Tsujii, Hirofumi Kuroda, Yoshikazu Furusawa, Katsuhiko Hirota
  • Patent number: 5476955
    Abstract: Disclosed herein are a quinone derivative represented by the following formula: ##STR1## wherein E.sup.1 and E.sup.2 are identical with or different from each other and mean individually a lower alkyl or lower alkoxy group, or may form an aromatic ring together, E.sup.3 denotes a lower alkyl group, n stands for 0 or an integer of 1-9, and a linkage ------ is a single or double bond, such as a vitamin K derivative or coenzyme Q derivative; and a process for the preparation of the quinone derivative at a high yield without forming any geometric isomer; as well as a 1,4,4.sub.a,8.sub.a -tetrahydro-4.sub.a .alpha.-alkenyl-1.alpha.,4.alpha.-methanonaphthalene-5,8-dione derivative which is useful as an intermediate for the preparation of the quinone derivative.
    Type: Grant
    Filed: March 1, 1994
    Date of Patent: December 19, 1995
    Assignee: Eisai Chemical Co., Ltd.
    Inventors: Kimio Hamamura, Tetsuo Iwama, Chiaki Seki, Masayuki Konishi
  • Patent number: 5428173
    Abstract: A process is provided for the preparation of an aminothiadiazolylacetyl halide derivative represented by the following formula (II): ##STR1## wherein R.sup.1 represents a lower alkyl, cycloalkyl or halogenated lower alkyl group; and R.sup.2 represents an amino-protecting group or a hydrogen atom, or a salt thereof, which process uses as the starting material a compound represented by the following formula (I): ##STR2## wherein R.sup.1 and R.sup.2 have the same meanings as defined above, or a salt thereof.
    Type: Grant
    Filed: September 30, 1993
    Date of Patent: June 27, 1995
    Assignee: Eisai Chemical Co., Ltd.
    Inventors: Takeo Kanai, Akio Imai, Katsuhiko Sato, Homare Shinohara, Kazumi Oishi
  • Patent number: 5412124
    Abstract: Disclosed herein are a naphthoquinone derivative represented by the following formula: ##STR1## wherein R.sup.1 means a hydrogen atom or methyl group, R.sup.2 is a hydrogen atom or methyl group, n stands for 0 or an integer of 1-9, and a linkage is a single bond or double bond with the proviso that if n is an integer of 2-9, the linkages may be identical with or different optionally from each other, such as a vitamin K derivative; and a process for producing the naphthoquinone derivative at a high yield without forming any geometric isomer; as well as 1,4,4.sub.a,5,8,9.sub.a -hexahydro-4.sub.a .alpha.-alkenyl-1.alpha.,4.alpha.-methanoanthraquinone derivatives and 1,4,4.sub.a,5,8,9.sub.a -hexahydro-1.alpha.,4.alpha.-methanoanthraquinone derivatives which are useful as intermediates for the preparation of the naphthoquinone derivatives.
    Type: Grant
    Filed: July 26, 1994
    Date of Patent: May 2, 1995
    Assignee: Eisai Chemical Co., Ltd.
    Inventors: Kimio Hamamura, Chiaki Seki, Masayuki Konishi