Patents by Inventor Masanobu Yatagai

Masanobu Yatagai 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).

  • Method for purifying nucleic acid derivatives
    Patent number: 6114525
    Abstract: A pure (-)-9-[1'S, 2'R-bis(hydroxymethyl)cyclopropan-1'-yl]methylguanine is prepared by:suspending or dissolving a mixture comprising (-)-9-[1'S, 2'R-bis(hydroxymethyl)cyclopropan-1'-yl]methylguanine and (7-[1'S,2'R-bis(hydroxymethyl)cyclopropan-1'-yl]methylguanine in an alcohol or a hydrous alcohol, reacting the resulting suspension or solution with an alkali metal hydroxide or alkoxide, and selectively precipitating crystals of nucleic acid derivatives of formula (I) ##STR1## wherein M represents an alkali metal.
    Type: Grant
    Filed: July 10, 1998
    Date of Patent: September 5, 2000
    Assignee: Ajinomoto Co., Inc.
    Inventors: Toshihiro Matsuzawa, Tohru Nishiwaki, Seiichi Nishi, Masanobu Yatagai
  • Method of producing optically active cyclopropane derivatives
    Patent number: 5900492
    Abstract: A method for resolving optically impure 3-oxa-2-oxobicyclo?3.1.0!hexane-1-carboxylic acid esters. A method is provided for producing a 1-alkoxycarbonyl-2-hydroxymethylcyclopropane-1-carboxylic acid.N-benzyl-.alpha.-phenylethylamine diastereomer salt. An enantiomer of N-benzyl-.alpha.-phenylethylamine is reacted with a 1-alkoxycarbonyl-2-hydroxymethylcyclopropane-1-carboxylic acid to produce a precipitate that is enriched in one diastereomer of the salt. After isolating the optically active salt, the N-benzyl-.alpha.-phenylethylamine may be separated to produce the corresponding 1-alkoxycarbonyl-2-hydroxymethylcyclopropane-1-carboxylic acid. Under acidic conditions, the carboxylic acid and hydroxyl groups undergo ring closure to afford the optically active 3-oxa-2-oxobicyclo?3.1.0!hexane-1-carboxylic acid ester.
    Type: Grant
    Filed: December 2, 1997
    Date of Patent: May 4, 1999
    Assignee: Ajinomoto Co., Inc.
    Inventors: Katsutoshi Sakata, Takashi Tsuji, Noriyasu Kataoka, Masanobu Yatagai
  • Process for asymmetrically reducing carbonyl compounds
    Patent number: 4943652
    Abstract: There is disclosed a process for asymmetrically reducing a carbonyl compound, which comprises reducing the carbonyl compound by the use of a reducing agent comprising (i) an optically active tartaric acid or ester thereof and (ii) a metal borohydride, thereby producing an optically active hydroxyl compound. The process can be used for the production of optically active hydroxyesters and alcohols from ketoesters and ketones. These products are useful for the production of medicaments and liquid crystals.
    Type: Grant
    Filed: November 14, 1988
    Date of Patent: July 24, 1990
    Assignee: Ajinomoto Co., Inc.
    Inventors: Masanobu Yatagai, Takashi Ohnuki