Patents by Inventor Chou-Hong Tann

Chou-Hong Tann 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: 20030204096
    Abstract: The application relates to a process for preparing a compound of Formula I 1
    Type: Application
    Filed: May 20, 2003
    Publication date: October 30, 2003
    Applicant: Schering Corporation
    Inventors: Xiaoyong Fu, Timothy L. Mc Allister, T.K. Thiruvengadam, Chou-Hong Tann
  • Patent number: 6627757
    Abstract: The application relates to a process for preparing a compound of Formula I This compound is an intermediate used to produce compounds that are useful as hypocholesterolemic agents in the treatment and prevention of atheroschlerosis.
    Type: Grant
    Filed: March 25, 2002
    Date of Patent: September 30, 2003
    Assignee: Schering Corporation
    Inventors: Xiaoyong Fu, Timothy L. McAllister, T. K. Thiruvengadam, Chou-Hong Tann
  • Publication number: 20020193607
    Abstract: The application relates to a process for preparing a compound of Formula I 1
    Type: Application
    Filed: March 25, 2002
    Publication date: December 19, 2002
    Applicant: Schering Corporation
    Inventors: Xiaoyong Fu, Timothy L. McAllister, T.K. Thiruvengadam, Chou-Hong Tann
  • Publication number: 20020049350
    Abstract: A single batch process for preparing (R)-benzyl-4-hydroxy-2-pentynoate by reacting (R)-3-butyn-2-ol with 1,1,1,3,3,3-hexamethyldisilazane to silylate the starting alcohol, followed by deprotonation with an alkyl lithium compound, then a reaction with a haloformate compound, and finally a hydrolysis reaction to arrive at the product ester.
    Type: Application
    Filed: June 26, 2001
    Publication date: April 25, 2002
    Inventors: Xiaoyong Fu, Chou-Hong Tann, T.K. Thiruvengadam, Jianguo Yin, Timothy L. McAllister, Cesar Colon
  • Patent number: 6207822
    Abstract: This invention provides a process for preparing the hypocholesterolemic compound comprising: (a) reacting p-fluorobenzoylbutyric acid with pivaloyl chloride and acylating the product with a chiral auxiliary to obtain a ketone of formula IV: (b) reducing the ketone of formula IV in the presence of a chiral catalyst to an alcohol: (c) reacting the chiral alcohol of step (b), an imine and a silyl protecting agent, then condensing the protected compounds to obtain a &bgr;-(substituted-amino)amide of formula VII: (d) cyclizing the &bgr;-(substituted-amino)amide of formula VII with a silylating agent and a fluoride ion catalyst to obtain a protected lactam of the formula VIII: and removing the protecting groups. The intermediates of formulas VII and VIII are also claimed.
    Type: Grant
    Filed: December 5, 1999
    Date of Patent: March 27, 2001
    Assignee: Schering Corporation
    Inventors: Tiruvettipuram K. Thiruvengadam, Xiaoyong Fu, Chou-Hong Tann, Timothy L. McAllister, John S. Chiu, Cesar Colon
  • Patent number: 6093812
    Abstract: This invention provides an improved process for producing azetidinones. More particularly, this invention provides the steps of producing an trans-azetidinone represented by the formula ##STR1## from a carboxylic acid R.sup.2 --D--CH.sub.2 COOH, an aldehyde R.sup.1 --A--CHO and an amine RNH.sub.2, by the steps of: (a1) converting a carboxylic acid to the corresponding acid chloride; (b1) deprotonating a chiral oxazolidinone and treating the resulting anion with the product of step (a1); (c1) enolizing the product of step (b1) and condensing with the aldehyde; (d1) hydrolyzing the product of step (c1); (e1) condensing the product of step (d1) with the amine; and (f1) cyclizing the product of step (e1). Alternatively, the process comprises (a2) enolizing the product of step (b1) and condensing, in the presence of a Lewis acid, with a Schiff's base prepared from the aldehyde and the amine; and (b2) cyclizing the product of step (a2).
    Type: Grant
    Filed: January 7, 1994
    Date of Patent: July 25, 2000
    Assignee: Schering Corporation
    Inventors: Tiruvettipuram K. Thiruvengadam, Chou-Hong Tann, Junning Lee, Timothy McAllister, Cesar Colon, Derek H. R. Barton, Ronald Breslow, Anantha Sudhakar
  • Patent number: 5886200
    Abstract: The invention provides an improved process for the preparation of 17-esters of 9.alpha.,21 -dihalo-pregnane-11.beta.,17.alpha.-diol-20-ones, and in particular for the preparation of 17-esters of anti-inflammatory steroids according to the following scheme: ##STR1## wherein RCO, R.sup.1, X, Y and the dotted line are as defined in the specification. The novel process is especially suitable for the preparation of Mometasone Furoate.
    Type: Grant
    Filed: June 25, 1997
    Date of Patent: March 23, 1999
    Assignee: Schering Corporation
    Inventors: Daw-Iong Albert Kwok, David J. S. Tsai, Chou-Hong Tann, Xiaoyong Fu
  • Patent number: 5750745
    Abstract: Described is a process for the regioselective dehydration of 11-hydroxy steroids using PCl.sub.5, PCl.sub.3, POCl.sub.3 or either SO.sub.2 Cl.sub.2 and imidazole, or PPh.sub.3 and CCl.sub.4. The disclosed process selectively forms .DELTA..sup.9,11 steroids from either 11-.alpha.- or 11-.beta.-hydroxy steroids, and can also be used for the one-step conversion of 11,21 -dihydroxy steroids to 21-chloro-.DELTA..sup.9,11 steroids. Also disclosed are processes for the regioselective conversion of 11-.beta.-chloro steroids to .DELTA..sup.9,11 steroids, and for regioselectively converting an 11,17,21-trihydroxy streoid to a 21-chloro-11,17-dihydroxy steroid.
    Type: Grant
    Filed: November 18, 1996
    Date of Patent: May 12, 1998
    Assignee: Schering Corporation
    Inventors: Xiaoyong Fu, Tiruvettipuram K. Thiruvengadam, Chou-Hong Tann, Junning Lee, Cesar Colon
  • Patent number: 5728827
    Abstract: This invention provides a process for preparing azetidinones useful as intermediates in the synthesis of penems and as hypocholesterolemic agents, particularly for azetidinones substituted in the C-3 and C-4 positions and optionally substituted at the ring nitrogen, comprising reacting a .beta.-(substituted-amino)amide, a .beta.-(substituted-amino)acid ester, or a .beta.-(substituted-amino)thiolcarbonic acid ester with a silylating agent and a cyclizing agent.
    Type: Grant
    Filed: January 4, 1996
    Date of Patent: March 17, 1998
    Assignee: Schering Corporation
    Inventors: Tiruvettipuram Kannapan Thiruvengadam, Timothy McAllister, Chou-Hong Tann
  • Patent number: 5616742
    Abstract: Described is a process for the regioselective dehydration of 11-hydroxy steroids using PCl.sub.5, PCl.sub.3, POCl.sub.3 or either SO.sub.2 Cl.sub.2 and imidazole, or PPh.sub.3 and CCl.sub.4. The disclosed process selectively forms .DELTA..sup.9,11 steroids from either 11-.alpha.- or 11-.beta.-hydroxy steroids, and can also be used for the one-step conversion of 11,21-dihydroxy steroids to 21-chloro-.DELTA..sup.9,11 steroids.Also disclosed are processes for the regioselective conversion of 11-.beta.-chloro steroids to .DELTA..sup.9,11 steroids, and for regioselectively converting an 11,17,21-trihydroxy streoid to a 21-chloro-11,17-dihydroxy steroid.
    Type: Grant
    Filed: May 22, 1995
    Date of Patent: April 1, 1997
    Assignee: Schering Corporation
    Inventors: Xiaoyong Fu, Tiruvettipuram K. Thiruvengadam, Chou-Hong Tann, Cesar Colon
  • Patent number: 5561227
    Abstract: This invention provides an improved process for producing azetidinones. More particularly, this invention provides the steps of producing an azetidinone represented by the formula I ##STR1## from a carboxylic acid R.sup.2 --D--CH.sub.2 COOH, an aldehyde R.sup.1 --A--CHO and an amine RNH.sub.2, by the steps of: (a) converting a carboxylic acid to the corresponding acid chloride; (b) deprotonating a chiral oxazolidinone and treating the resulting anion with the product of step (a); (c) enolizing the product of step (b) and condensing with an imine; and (d) cyclizing the product of step (c). Steps (c) and (d) of this process are as shown in the following reaction scheme.
    Type: Grant
    Filed: June 23, 1994
    Date of Patent: October 1, 1996
    Assignee: Schering Corporation
    Inventors: Tiruvettipuram K. Thiruvengadam, Chou-Hong Tann, Timothy L. McAllister
  • Patent number: 5539121
    Abstract: There is disclosed a novel formylating agent, 2-formylmercaptobenzothiazole.
    Type: Grant
    Filed: May 16, 1995
    Date of Patent: July 23, 1996
    Assignee: Schering Corporation
    Inventors: Chou-Hong Tann, Tiruvettipuram K. Thiruvengadam, John S. Chiu, Cesar Colon, Michael D. Green
  • Patent number: 5502222
    Abstract: Described is a process for the regioselective dehydration of 11-hydroxy steroids using PCl.sub.5, PCl.sub.3, POCl.sub.3 or either SO.sub. Cl.sub.2 and imidazole, or PPh.sub.3 and CCl.sub.4. The disclosed process selectively forms .increment..sup.9,11 steroids from either 11-.alpha.- or 11-.beta.-hydroxy steroids, and can also be used for the one-step conversion of 11,21-dihydroxy steroids to 21-chloro-.increment..sup.9,11 steroids.
    Type: Grant
    Filed: June 1, 1994
    Date of Patent: March 26, 1996
    Assignee: Schering Corporation
    Inventors: Xiaoyong Fu, Tiruvettipuram K. Thiruvengadam, Chou-Hong Tann, Junning Lee, Cesar Colon
  • Patent number: 5442047
    Abstract: An improved process for converting gentamicin B to isepamicin comprising forming 3,6'-di-N-formylgentamicin B, acylating the 1-amino group with an N-protected (S)-isoserine compound and removing all the blocking groups under conditions which result in high yields of isepamicin. A novel formylating agent, 2-formylmercaptobenzothiazole, and intermediate compounds are also disclosed.
    Type: Grant
    Filed: October 15, 1993
    Date of Patent: August 15, 1995
    Assignee: Schering Corporation
    Inventors: Chou-Hong Tann, Tiruvettipuram K. Thiruvengadam, John S. Chiu, Cesar Colon, Michael D. Green
  • Patent number: 5306817
    Abstract: This invention provides an improved process for producing azetidinones. More particularly, this invention provides the steps of producing an trans-azetidinone represented by the formula ##STR1## from a carboxylic acid R.sup.2 -D-CH.sub.2 -COOH, an aldehyde R.sup.1 -A-CHO and an amine RNH.sub.2, by the steps of: (a1) converting a carboxylic acid to the corresponding acid chloride; (b1) deprotonating a chiral oxazolidinone and treating the resulting anion with the product of step (a1); (c1) enolizing the product of step (b1) and condensing with the aldehyde; (d1) hydrolyzing the product of step (c1); (e1) condensing the product of step (d1) with the amine; and (f1) cyclizing the product of step (e1).Alternatively, the process comprises (a2) enolizing the product of step (b1) and condensing, in the presence of a Lewis acid, with a Schiff's base prepared from the aldehyde and the amine; and (b2) cyclizing the product of step (a2).
    Type: Grant
    Filed: October 19, 1992
    Date of Patent: April 26, 1994
    Assignee: Schering Corporation
    Inventors: Tiruvettipuram K. Thiruvengadam, Chou-Hong Tann, Junning Lee, Timothy McAllister, Anantha Sudhakar
  • Patent number: 5283359
    Abstract: The preparation of arylethanolamines, and in particular albuterol (salbutamol), together with their novel boron, acetal and hemi-acetal intermediates is described.
    Type: Grant
    Filed: March 1, 1993
    Date of Patent: February 1, 1994
    Assignee: Schering Corp.
    Inventors: Chou-Hong Tann, T. K. Thiruvengadam, John Chiu, Michael Green, Timothy L. McAllister, Cesar Colon, Junning Lee
  • Patent number: 4879377
    Abstract: Process for producing 1-halo-2-deoxy-2-fluoroarabinofuranoside derivatives bearing protective ester groups from 1,3,5-tri-O-acylribofuranose; the 1-halo compounds are intermediates in the synthesis of therapeutically active nucleosidic compounds.
    Type: Grant
    Filed: July 28, 1988
    Date of Patent: November 7, 1989
    Assignee: Bristol-Myers Company
    Inventors: Steven P. Brundidge, Henry G. Howell, Chester Sapino, Jr., Chou Hong-Tann
  • Patent number: 4831123
    Abstract: A high yielding process for converting 3,2',6'-tri-N-acetyl sisomicin to netilmicin comprising the step of silylating the starting material at the 5,2' positions, and optionally at the 4' position, converting the 1-amino substituent to a 1-N-imino substituent, converting the imino to an ethylamino, deprotecting the compound and recovering netilmicin. Also disclosed are novel intermediate compounds.
    Type: Grant
    Filed: November 6, 1986
    Date of Patent: May 16, 1989
    Assignee: Schering Corporation
    Inventors: Chou-Hong Tann, Tiruvettipuram K. Thiruvengadam, John S. Chiu, Cesar Colon