Patents by Inventor Daniel A. Aguilar

Daniel A. Aguilar 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).

  • Ligands for MRI contrast agent
    Patent number: 5861138
    Abstract: Novel ligands for use in MRI contrast agents and which have the formula ##STR1## wherein R.sub.1 -R.sub.14, M", l, m, and n are defined herein.
    Type: Grant
    Filed: November 20, 1996
    Date of Patent: January 19, 1999
    Assignee: Hoechst Celanese Corp.
    Inventors: Wei-Jun Peng, Daniel A. Aguilar
  • Thio-substituted pyridines as MRI ligand precursors
    Patent number: 5824288
    Abstract: Novel precursors of ligands or use in MRI contrast agents and which have the formula ##STR1## wherein R.sub.2-R.sub.10 are defined herein.
    Type: Grant
    Filed: August 21, 1997
    Date of Patent: October 20, 1998
    Assignee: Hoechst Celanese Corporation
    Inventors: Wei-Jen Peng, Humberto Ramos, Jr., Daniel A. Aguilar
  • Production of acetaminophen
    Patent number: 5155273
    Abstract: N-acetyl-para-aminophenol is prepared by contacting 4-hydroxyacetophenone oxime with a Beckmann rearrangement catalyst in an alkyl alkanoate reaction solvent. An integrated process is disclosed wherein 4-hydroxyacetophenone is reacted with a hydroxylamine salt and a base to obtain 4-hydroxyacetophenone oxime, the oxime product is extracted from the resulting reaction mixture with a substantially water-immiscible solvent, and the mixture of oxime and substantially water-immiscible solvent is contacted with a Beckmann rearrangement catalyst to produce N-acetyl-para-aminophenol. Novel Beckamnn rearrangement catalysts are used to limit by-product formation in the ester solvent.
    Type: Grant
    Filed: July 20, 1990
    Date of Patent: October 13, 1992
    Assignee: Hoechst Celanese Corporation
    Inventors: John R. Fritch, O. Stanley Fruchey, Theodore Horlenko, Daniel A. Aguilar, Charles B. Hilton, Phillip S. Snyder, William J. Seeliger
  • Synthesis of 1-aminoanthraquinone
    Patent number: 5132437
    Abstract: 1-Aminoanthraquinone (1-AAQ) is synthesized by the reaction of 2-chlorobenzyl chloride and xylene in the presence of a solid acid catalyst to yield 2-chloro dimethyldiphenylmethane, subsequent oxidation of the methyl groups, ring closure to form a 1-chloroanthraquinone carboxylic acid, replacement of the 1-chloro group with ammonia, and decarboxylation.
    Type: Grant
    Filed: February 12, 1991
    Date of Patent: July 21, 1992
    Assignee: Hoechst Celanese Corporation
    Inventors: Mohammad Aslam, Daniel A. Aguilar
  • Synthesis of 1-aminoanthraquinone
    Patent number: 5130448
    Abstract: 1-Aminoanthraquinone (1-AAQ) is synthesized by the condensation of 2-substituted benzoic acid and xylene to yield 2-substituted-dimethylbenzophenone, subsequent oxidation of the methyl groups, ring closure to form a 1-substituted anthraquinone carboxylic acid, replacement of the 1-substituent with ammonia, and decarboxylation.
    Type: Grant
    Filed: February 12, 1991
    Date of Patent: July 14, 1992
    Assignee: Hoechst Celanese Corporation
    Inventors: Mohammad Aslam, Daniel A. Aguilar