Patents by Inventor Varadaraj Elango

Varadaraj Elango 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: 6555704
    Abstract: A method is provided for the preparation of alpha-aryl-propionic acids such as ibuprofen by carbonylating the corresponding 1-arylethyl halide in an acidic aqueous medium containing a palladium catalyst. In the preparation of ibuprofen, 1-(4′-isobutylphenyl)ethyl halide is reacted with carbon monoxide in an acidic aqueous medium containing a palladium catalyst.
    Type: Grant
    Filed: May 22, 1995
    Date of Patent: April 29, 2003
    Assignee: BASF Corporation
    Inventor: Varadaraj Elango
  • Patent number: 5744648
    Abstract: A new process for the manufacture of 1,3-cyclohexanedione is disclosed wherein a selected resorcinol is reduced with a hydrogen donor in the presence of a metal catalyst to produce a product which is then neutralized with an acid.
    Type: Grant
    Filed: August 1, 1996
    Date of Patent: April 28, 1998
    Assignee: Hoechst Celanese Corporation
    Inventors: Varadaraj Elango, Rajagopal Sakamuri
  • Patent number: 5405987
    Abstract: The present invention pertains to a method of preparing substituted and unsubstituted N-hydroxy-2-aminobutane diacid derivatives which can be dehydrated to 2-aminobut-2-ene dioic acid derivatives, which can be subsequently converted to pyridine and quinoline derivatives.
    Type: Grant
    Filed: March 28, 1991
    Date of Patent: April 11, 1995
    Assignee: Hoechst Celanese Corporation
    Inventors: Varadaraj Elango, Donald R. Larkin, John R. Fritch, Michael P. Bodman, Werner H. Mueller, Bernard F. Gupton, John C. Saukaitis
  • Patent number: 5322948
    Abstract: The present invention pertains to a method of preparing substituted and unsubstituted N-hydroxy-2-aminobutane diacid derivatives. The invention also pertains to the use of N-hydroxy-2-aminoethane derivatives (including the N-hydroxy-2-aminobutane diacid derivatives) in the preparation of pyridine derivatives.
    Type: Grant
    Filed: January 2, 1992
    Date of Patent: June 21, 1994
    Assignee: Hoechst Celanese Corporation
    Inventors: Varadaraj Elango, Donald R. Larkin, John R. Fritch, Michael P. Bodman, Werner H. Mueller, Bernard F. Gupton, John C. Saukaitis
  • Patent number: 5300675
    Abstract: This invention discloses a novel process for preparing cinnamic acid derivatives. The inventive process is illustrated by the synthesis of 2-ethylhexyl p-methoxycinnamate by coupling p-methoxybenzenediazonium tetrafluoroborate with 2-ethylhexyl acrylate in an alcohol solution, wherein a buffer compound such as sodium acetate is present, the coupling reaction being catalyzed by a mixture comprising a copper salt, such as cuprous chloride, and a palladium salt, such as Li.sub.2 PdCl.sub.4.
    Type: Grant
    Filed: June 29, 1993
    Date of Patent: April 5, 1994
    Assignee: Hoechst Celanese Corp.
    Inventor: Varadaraj Elango
  • Patent number: 5235090
    Abstract: A method for synthesizing 2-(4-amidophenoxy)alkanoic acids and esters and 2-(4-aminophenoxy)alkanoic acids and esters by reacting a hydroxyaromatic ketone derivative with a 2-substituted alkanoic acid or ester under basic conditions and thereafter reacting with a hydroxylamine derivative and conducting a Beckmann Rearrangement with subsequent solvolysis.
    Type: Grant
    Filed: November 19, 1992
    Date of Patent: August 10, 1993
    Assignee: Hoechst Celanese Corp.
    Inventor: Varadaraj Elango
  • Patent number: 5225603
    Abstract: An intermediate for the manufacture of nabumetone, 4-(6'-methoxy-2'-naphthyl)-3-buten-2-one, is prepared by contacting 2-bromo-6-methoxynaphphalene with methyl vinyl ketone in the presence of a palladium catalyst at from about 50.degree. C. to about 200.degree. C. for a time sufficient to cause substantially complete reaction to occur.
    Type: Grant
    Filed: June 17, 1988
    Date of Patent: July 6, 1993
    Assignee: Hoechst Celanese Corporation
    Inventors: Mohammad Aslam, Varadaraj Elango
  • Patent number: 5179229
    Abstract: A process for the preparation of 2,2-diorgano-3-arylpropionic acids is disclosed by the carbonylation of corresponding 2,2-diorgano-1-aryl ethanol in the presence of a Lewis acid catalyst. Furthermore, a process for the production of 2,2-diorgano-3-arylpropionic esters is disclosed by reacting a corresponding 2,2-diorgano-1-aryl ethanol with carbon monoxide and an alcohol in the presence of a Lewis acid catalyst.
    Type: Grant
    Filed: April 24, 1992
    Date of Patent: January 12, 1993
    Assignee: Hoechst Celanese Corporation
    Inventor: Varadaraj Elango
  • Patent number: 5012007
    Abstract: A method is provided for the production of 2,2-diorgano-1-indanones, e.g., 2,2-dimethyl-1-indanone, by reacting an alcohol which is the corresponding (diorganosubstitutedmethyl)phenyl(or substitutedphenyl)carbinol, e.g., 2-methyl-1-phenyl-1-propanol, with carbon monoxide in the presence of a Lewis acid catalyst, e.g., hydrogen fluoride, with any substituents on the phenyl group of the alcohol being hydroxy or organo. The foregoing reaction is preferably integrated with the preparation of the feed alcohol by reducing the corresponding (diorganosubstitutedmethyl)phenyl(or substitutedphenyl)ketone, e.g., isobutyrophenone, with a reducing agent containing available hydrogen, e.g., sodium borohydride, or with hydrogen gas in the presence of a hydrogenation catalyst.
    Type: Grant
    Filed: October 5, 1989
    Date of Patent: April 30, 1991
    Inventor: Varadaraj Elango
  • Patent number: 5008439
    Abstract: A method for synthesizing 2-(4-hydroxyphenoxy)alkanoic acid esters by reacting a hydroxyaromatic ketone derivative with a 2-substituted alkanoic acid ester under basic conditions and thereafter oxidizing the intermediate with subsequent hydrolysis.
    Type: Grant
    Filed: March 21, 1988
    Date of Patent: April 16, 1991
    Assignee: Hoechst Celanese Corporation
    Inventors: Varadaraj Elango, Kenneth G. Davenport
  • Patent number: 4981995
    Abstract: A method is provided for the preparation of ibuprofen by carbonylating 1-(4'-isobutylphenyl)ethanol (IBPE) with carbon monoxide in an acidic aqueous medium, e.g. containing at least 10% of water based on the weight of IBPE initially added, at a temperature of at least about 10.degree. C. and a carbon monoxide pressure of at least about 500 psig, and in the presence of (1) a catalyst complex consisting essentially of a palladium compound in which the palladium has a valence of zero to 2 and is complexed with at least one monodentate phosphine ligand miscible with the organic phase of the reaction medium, the phosphorus/palladium mole ratio in said palladium compound and ligand being at least about 2:1 when the palladium/IBPE mole ratio is such that palladium=1 and IBPE=10,000 or more; (2) dissociated hydrogen ions from an acid which is substantially completely ionizable in dilute aqueous solution such that the mole ratio of hydrogen ions to IBPE added to the reaction zone is at least about 0.
    Type: Grant
    Filed: March 28, 1990
    Date of Patent: January 1, 1991
    Inventors: Varadaraj Elango, Mark A. Murphy, Brad L. Smith, Kenneth G. Davenport, Graham N. Mott, Edward G. Zey, Gary L. Moss
  • Patent number: 4908476
    Abstract: A method for synthesizing 2-(4-hydroxyphenoxy)alkanoic acids by reacting a hydroxyaromatic ketone derivative with a 2-substituted alkanoic acid under basic conditions and thereafter oxidizing the intermediate with subsequent hydrolysis.
    Type: Grant
    Filed: March 21, 1988
    Date of Patent: March 13, 1990
    Assignee: Hoechst Celanese Corporation
    Inventors: Varadaraj Elango, Kenneth G. Davenport
  • Patent number: H1760
    Abstract: A process for preparing bis alkylene glycol esters of an alkali metal salt of 5-sulfoisophthalic acid. The subject compound is useful in preparing modified polyesters which can be dyed with basic or cationic dyes. The process is economical and low cost since intermediate reaction products are not purified.
    Type: Grant
    Filed: January 8, 1997
    Date of Patent: November 3, 1998
    Assignee: Hoechst Celanese Corporation
    Inventors: Varadaraj Elango, William R. Lee, Jeffrey S. Hurley, Cheryl A. Littau