Patents by Inventor Yun Gao

Yun Gao 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: 5419817
    Abstract: A process is disclosed in which optically active glycols are produced through an electrolytic asymmetric dihydroxylation (ADH) reaction involving olefins as substrates. The ADH reaction is mediated by a catalytically active amount of osmium tetroxide or osmium-containing precursor in a protic medium in the presence of chiral ligand. Any lower valent osmium species produced in the course of the ADH reaction is regenerated electrolytically either directly in the absence of a secondary oxidant or indirectly in the presence of a secondary oxidant that itself undergoes electrolytic regeneration.
    Type: Grant
    Filed: January 18, 1994
    Date of Patent: May 30, 1995
    Assignee: Sepracor Inc.
    Inventors: Yun Gao, Charles M. Zepp
  • Patent number: 5399765
    Abstract: The invention relates to a method for producing albuterol by the resolution of a mixture of enantiomers of 5-[2-[(1,1-dimethylethyl)amino]-1-hydroxyethyl]-2-hydroxybenzoate using ditoluoyltartaric acid.
    Type: Grant
    Filed: May 23, 1994
    Date of Patent: March 21, 1995
    Assignee: Sepracor, Inc.
    Inventors: Yun Gao, Charles M. Zepp
  • Patent number: 5324860
    Abstract: A process for the synthesis of 3-5-tert-butylsalicylaldehyde from 2,4-di-tert-butylphenol and hexamethylenetetramine is disclosed. The reaction provides 3,5-tert-butylsalicylaldehyde in commercially attractive yields from readily available starting materials.
    Type: Grant
    Filed: October 27, 1993
    Date of Patent: June 28, 1994
    Assignee: Sepracor, Inc.
    Inventors: Yun Gao, Xiaoyi Nie
  • Patent number: 5321143
    Abstract: A ruthenium catalyzed method to synthesize cyclic sulfate compounds from the corresponding cyclic sulfites, and the cyclic sulfate reaction products obtained by this method. These cyclic sulfates further react with selected nucleophiles to give various substituted products. The method is an efficient means for the synthesis of chiral building blocks from tartaric acid enantiomers in high yields using an overall two-stage, one-pot reaction procedure. The chiral compounds can be transformed by nucleophilic reactions into chiral building blocks useful for the synthesis of natural biologically active products, such as antibiotics and pheromones.
    Type: Grant
    Filed: June 7, 1991
    Date of Patent: June 14, 1994
    Assignee: Massachusetts Institute of Technology
    Inventors: K. Barry Sharpless, Yun Gao
  • Patent number: 5302257
    Abstract: A process is disclosed in which optically active glycols are produced through an electrolytic asymmetric dihydroxylation (ADH) reaction involving olefins as substrates. The ADH reaction is mediated by a catalytically active amount of osmium tetroxide or osmium-containing precursor in a protic medium in the presence of chiral ligand. Any lower valent osmium species produced in the course of the ADH reaction is regenerated electrolytically either directly in the absence of a secondary oxidant or indirectly in the presence of a secondary oxidant that itself undergoes electrolytic regeneration.
    Type: Grant
    Filed: February 21, 1992
    Date of Patent: April 12, 1994
    Assignee: Sepracor, Inc.
    Inventors: Yun Gao, Charles M. Zepp
  • Patent number: 5286899
    Abstract: An efficient and commercially-viable method for the stereoselective transformation of a diol to an alcohol is disclosed. The present method is particularly well-suited for the preparation of the unnatural D-isomer of malic acid or its derivatives from the abundant naturally occurring L-tartaric acid or derivatives thereof.
    Type: Grant
    Filed: August 27, 1992
    Date of Patent: February 15, 1994
    Assignee: Sepracor, Inc.
    Inventor: Yun Gao
  • Patent number: 5271812
    Abstract: The invention relates to a process for the production of cyclic sulfates and cyclic sulfamidates from the corresponding cyclic sulfite and cyclic sulfamidite substrate, respectively. The method involves the electrolysis of a solvent mixture containing active metal species, non-metal oxidant species and substrate.
    Type: Grant
    Filed: June 19, 1991
    Date of Patent: December 21, 1993
    Assignee: Sepracor, Inc.
    Inventors: Yun Gao, Charles M Zepp
  • Patent number: 5258517
    Abstract: A biocatalytic method of preparing optically pure precursors of paroxetine and a method of preparing paroxetine therefrom are disclosed. A racemic trans ester precursor compound of paroxetine is first prepared. The racemic trans ester precursor compound comprises a mixture of (3S,4R) and (3R,4S) enantiomers. The (3R,4S) enantiomer is hydrolyzed biocatalytically to the corresponding (3R,4S)-trans carboxylic acid or alternatively, the (3S,4R) enantiomer is biocatalytically hydrolyzed the to (3S,4R)-trans carboxylic acid in a reaction catalyzed by a isolated enzyme or a microorganism. In the first instance, the unhydrolyzed (3S,4R) enantiomer is separated from the (3R,4S)-trans carboxylic acid, whereas in the second instance the (3S,4R)-trans carboxylic acid is separated from the unhydrolyzed (3R,4S) enantiomer. The (3S,4R) enantiomer obtained following the selective hydrolysis is reduced to form a (-)-trans-(3S,4R) primary alcohol precursor of paroxetine.
    Type: Grant
    Filed: August 6, 1992
    Date of Patent: November 2, 1993
    Assignee: Sepracor, Inc.
    Inventors: Charles M. Zepp, Yun Gao, Donald L. Heefner
  • Patent number: 5189200
    Abstract: An efficient and commerically-viable method for the stereoselective transformation of a diol to an alcohol is disclosed. The present method is particularly well-suited for the preparation of the unnatural D-isomer of malic acid or its derivatives from the abundant naturally occurring L-tartaric acid or derivatives thereof.
    Type: Grant
    Filed: December 21, 1990
    Date of Patent: February 23, 1993
    Assignee: Sepracor, Inc.
    Inventor: Yun Gao
  • Patent number: 5112990
    Abstract: A ruthenium catalyzed method to synthesize cyclic sulfate compounds from the corresponding cyclic sulfites, and the cyclic sulfate reaction products obtained by this method. These cyclic sulfates further react with selected nucleophiles to give various substituted products. The method is an efficient means for the synthesis of chiral building blocks from tartaric acid enantiomers in high yields using an overall two-stage, one-pot reaction procedure. The chiral compounds can be transformed by nucleophilic reactions into chiral building blocks useful for the synthesis of natural biologically active products, such as antibiotics and pheromones.
    Type: Grant
    Filed: June 21, 1989
    Date of Patent: May 12, 1992
    Assignee: Massachusetts Institute of Technology
    Inventors: K. Barry Sharpless, Yun Gao
  • Patent number: 5023342
    Abstract: A ruthenium catalyzed method to synthesize cyclic sulfate compounds from the corresponding cyclic sulfites, and the cyclic sulfate reaction products obtained by this method. These cyclic sulfates further react with selected nucleophiles to give various substituted products. The method is an efficient means for the synthesis of chiral building blocks from tartaric acid enantiomers in high yields using an overall two-stage, one-pot reaction procedure. The chiral compounds can be transformed by nucleophilic reactions into chiral building blocks useful for the synthesis of natural biologically active products, such as antibiotics and pheromones.
    Type: Grant
    Filed: May 26, 1988
    Date of Patent: June 11, 1991
    Assignee: Massachusetts Institute of Technology
    Inventors: K. Barry Sharpless, Yun Gao