Patents by Inventor Yigang Zhao

Yigang Zhao 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).

  • Publication number: 20150166500
    Abstract: Methods are described for efficient and regioselective reactions that are Ru-catalyzed and either (i) amide-directed C—H, C—N, C—O activation/C—C bond forming reactions, (ii) ester-directed C—O and C—N activation/C—C bond forming reactions, or (iii) amide-directed C—O activation/hydrodemethoxylation reactions. All of these reactions of directed C—H, C—N, C—O activation/coupling reactions establish a catalytic base-free DoM-cross coupling process at non-cryogenic temperature. High regioselectivity, yields, operational simplicity, low cost, and convenient scale-up make these reactions suitable for industrial applications. Many previously unknown amide-substituted or ester-substituted aryl and heteroaryl compounds are presented with synthetic details also provided.
    Type: Application
    Filed: November 14, 2014
    Publication date: June 18, 2015
    Inventors: Yigang Zhao, Victor A. Snieckus
  • Publication number: 20120302752
    Abstract: Methods are described for efficient and regioselective reactions that are Ru-catalyzed and either (i) amide-directed C—H, C—N, C—O activation/C—C bond forming reactions, (ii) ester-directed C—O and C—N activation/C—C bond forming reactions, or (iii) amide-directed C—O activation/hydrodemethoxylation reactions. All of these reactions of directed C—H, C—N, C—O activation/coupling reactions establish a catalytic base-free DoM-cross coupling process at non-cryogenic temperature. High regioselectivity, yields, operational simplicity, low cost, and convenient scale-up make these reactions suitable for industrial applications. Many previously unknown amide-substituted or ester-substituted aryl and heteroaryl compounds are presented with synthetic details also provided.
    Type: Application
    Filed: May 24, 2012
    Publication date: November 29, 2012
    Inventors: Yigang Zhao, Victor A. Snieckus
  • Patent number: 8168833
    Abstract: Embodiments of the invention provide a method of using Schwartz Reagent, Cp2Zr(H)Cl, without accumulating or isolating it. Methods provide mixtures of Cp2ZrCl2, reductants that selectively reduce Cp2ZrCl2, and substrates. After reaction of Cp2ZrCl2 and the reductant, an intermediate reduction product is formed, apparently Schwartz Reagent. The in situ Schwartz Reagent then selectively reduces certain functional groups on the substrate. Substrates include tertiary amides, tertiary benzamides, aryl O-carbamates, and heteroaryl N-carbamates, which are reduced to aldehydes, benzaldehydes, aromatic alcohols, and heteroaromatics, respectively. Compared to prior methods, reagents are inexpensive and stable, reaction times are short, and reaction temperature in certain cases is conveniently room temperature. It has been estimated that using the in situ method described herein instead of synthesized or commercially obtained Schwartz Reagent provides a 50% reduction in cost.
    Type: Grant
    Filed: December 3, 2009
    Date of Patent: May 1, 2012
    Assignee: Queen's University at Kingston
    Inventors: Yigang Zhao, Victor A. Snieckus
  • Publication number: 20100145060
    Abstract: Embodiments of the invention provide a method of using Schwartz Reagent, Cp2Zr(H)Cl, without accumulating or isolating it. Methods provide mixtures of Cp2ZrCl2, reductants that selectively reduce Cp2ZrCl2, and substrates. After reaction of Cp2ZrCl2 and the reductant, an intermediate reduction product is formed, apparently Schwartz Reagent. The in situ Schwartz Reagent then selectively reduces certain functional groups on the substrate. Substrates include tertiary amides, tertiary benzamides, aryl O-carbamates, and heteroaryl N-carbamates, which are reduced to aldehydes, benzaldehydes, aromatic alcohols, and heteroaromatics, respectively. Compared to prior methods, reagents are inexpensive and stable, reaction times are short, and reaction temperature in certain cases is conveniently room temperature. It has been estimated that using the in situ method described herein instead of synthesized or commercially obtained Schwartz Reagent provides a 50% reduction in cost.
    Type: Application
    Filed: December 3, 2009
    Publication date: June 10, 2010
    Inventors: Yigang Zhao, Victor A. Snieckus