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: 20030204096Abstract: The application relates to a process for preparing a compound of Formula I 1Type: ApplicationFiled: May 20, 2003Publication date: October 30, 2003Applicant: Schering CorporationInventors: Xiaoyong Fu, Timothy L. Mc Allister, T.K. Thiruvengadam, Chou-Hong Tann
-
Patent number: 6627757Abstract: 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: GrantFiled: March 25, 2002Date of Patent: September 30, 2003Assignee: Schering CorporationInventors: Xiaoyong Fu, Timothy L. McAllister, T. K. Thiruvengadam, Chou-Hong Tann
-
Publication number: 20020193607Abstract: The application relates to a process for preparing a compound of Formula I 1Type: ApplicationFiled: March 25, 2002Publication date: December 19, 2002Applicant: Schering CorporationInventors: Xiaoyong Fu, Timothy L. McAllister, T.K. Thiruvengadam, Chou-Hong Tann
-
Publication number: 20020049350Abstract: 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: ApplicationFiled: June 26, 2001Publication date: April 25, 2002Inventors: Xiaoyong Fu, Chou-Hong Tann, T.K. Thiruvengadam, Jianguo Yin, Timothy L. McAllister, Cesar Colon
-
Patent number: 6207822Abstract: 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: GrantFiled: December 5, 1999Date of Patent: March 27, 2001Assignee: Schering CorporationInventors: Tiruvettipuram K. Thiruvengadam, Xiaoyong Fu, Chou-Hong Tann, Timothy L. McAllister, John S. Chiu, Cesar Colon
-
Patent number: 6093812Abstract: 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: GrantFiled: January 7, 1994Date of Patent: July 25, 2000Assignee: Schering CorporationInventors: Tiruvettipuram K. Thiruvengadam, Chou-Hong Tann, Junning Lee, Timothy McAllister, Cesar Colon, Derek H. R. Barton, Ronald Breslow, Anantha Sudhakar
-
Patent number: 5886200Abstract: 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: GrantFiled: June 25, 1997Date of Patent: March 23, 1999Assignee: Schering CorporationInventors: Daw-Iong Albert Kwok, David J. S. Tsai, Chou-Hong Tann, Xiaoyong Fu
-
Patent number: 5750745Abstract: 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: GrantFiled: November 18, 1996Date of Patent: May 12, 1998Assignee: Schering CorporationInventors: Xiaoyong Fu, Tiruvettipuram K. Thiruvengadam, Chou-Hong Tann, Junning Lee, Cesar Colon
-
Patent number: 5728827Abstract: 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: GrantFiled: January 4, 1996Date of Patent: March 17, 1998Assignee: Schering CorporationInventors: Tiruvettipuram Kannapan Thiruvengadam, Timothy McAllister, Chou-Hong Tann
-
Patent number: 5616742Abstract: 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: GrantFiled: May 22, 1995Date of Patent: April 1, 1997Assignee: Schering CorporationInventors: Xiaoyong Fu, Tiruvettipuram K. Thiruvengadam, Chou-Hong Tann, Cesar Colon
-
Patent number: 5561227Abstract: 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: GrantFiled: June 23, 1994Date of Patent: October 1, 1996Assignee: Schering CorporationInventors: Tiruvettipuram K. Thiruvengadam, Chou-Hong Tann, Timothy L. McAllister
-
Patent number: 5539121Abstract: There is disclosed a novel formylating agent, 2-formylmercaptobenzothiazole.Type: GrantFiled: May 16, 1995Date of Patent: July 23, 1996Assignee: Schering CorporationInventors: Chou-Hong Tann, Tiruvettipuram K. Thiruvengadam, John S. Chiu, Cesar Colon, Michael D. Green
-
Patent number: 5502222Abstract: 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: GrantFiled: June 1, 1994Date of Patent: March 26, 1996Assignee: Schering CorporationInventors: Xiaoyong Fu, Tiruvettipuram K. Thiruvengadam, Chou-Hong Tann, Junning Lee, Cesar Colon
-
Patent number: 5442047Abstract: 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: GrantFiled: October 15, 1993Date of Patent: August 15, 1995Assignee: Schering CorporationInventors: Chou-Hong Tann, Tiruvettipuram K. Thiruvengadam, John S. Chiu, Cesar Colon, Michael D. Green
-
Patent number: 5306817Abstract: 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: GrantFiled: October 19, 1992Date of Patent: April 26, 1994Assignee: Schering CorporationInventors: Tiruvettipuram K. Thiruvengadam, Chou-Hong Tann, Junning Lee, Timothy McAllister, Anantha Sudhakar
-
Patent number: 5283359Abstract: The preparation of arylethanolamines, and in particular albuterol (salbutamol), together with their novel boron, acetal and hemi-acetal intermediates is described.Type: GrantFiled: March 1, 1993Date of Patent: February 1, 1994Assignee: Schering Corp.Inventors: Chou-Hong Tann, T. K. Thiruvengadam, John Chiu, Michael Green, Timothy L. McAllister, Cesar Colon, Junning Lee
-
Patent number: 4879377Abstract: 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: GrantFiled: July 28, 1988Date of Patent: November 7, 1989Assignee: Bristol-Myers CompanyInventors: Steven P. Brundidge, Henry G. Howell, Chester Sapino, Jr., Chou Hong-Tann
-
Patent number: 4831123Abstract: 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: GrantFiled: November 6, 1986Date of Patent: May 16, 1989Assignee: Schering CorporationInventors: Chou-Hong Tann, Tiruvettipuram K. Thiruvengadam, John S. Chiu, Cesar Colon