Patents by Inventor Kalidas Paul

Kalidas Paul 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: 6030643
    Abstract: Pharmaceutical compositions containing potassium, sodium or Tris salt of oxaprozin as an active agent. The pharmaceutical compositions of the present invention are useful in eliminating or ameliorating pain and in the treatment of inflammation and inflammation associated disorders such as rheumatoid arthritis and osteoarthritis.
    Type: Grant
    Filed: May 16, 1997
    Date of Patent: February 29, 2000
    Assignee: G.D. Searle & Co.
    Inventors: Mark E. Adams, Subhash Desai, Aziz Karim, Kalidas Paul, Douglas J. Schaaf, David J. Zold
  • Patent number: 5220019
    Abstract: Disclosed is a process for the preparation of 3-aryl-3-aminoalkyl-2,6-dioxohexahydropridines and particularly the compound 3-[3-(dimethylamino)propyl]3-(3 methoxyphenyl)-4, 4-dimethyl-2,6-piperidinedione, monohydrochloride, which is useful as an antidepressant.The process of the present invention comprises the condensation of a sterically hindered nitrile with a sterically hindered .alpha.,.beta.-unsaturated diester to produce a nitrile diester. These compounds can then undergo acid catalyzed cyclization and decarboalkoxylation in a one step process to provide the desired 3-aryl-3-aminoalkyl-2,6 -dioxohexahydropyridine.
    Type: Grant
    Filed: March 27, 1992
    Date of Patent: June 15, 1993
    Assignee: G. D. Searle & Co.
    Inventors: John H. Dygos, Kathleen T. McLaughlin, John S. Ng, Kalidas Paul
  • Patent number: 5104990
    Abstract: Disclosed is a process for the preparation of 3-aryl-3-aminoalkyl-2,6-dioxohexahydropridines and particularly the compounds 3-[3-(dimethylamino)propyl]-3-(3-methoxyphenyl)-4, 4-dimethyl-2,6-piperidinedione, monohydrochloride, which is useful as an antidepressant.the process of the present invention comprises the condensation of a sterically hindered nitrile with a sterically hindered .alpha., .beta.-unsaturated diester to produce a nitrile diester. These compounds can then undergo acid catalyzed cyclization and decarboalkoxylation in a one step process to provide the desired 3-aryl-3-aminoalkyl-2,6-dioxohexahydropyridine.
    Type: Grant
    Filed: February 27, 1990
    Date of Patent: April 14, 1992
    Assignee: G. D. Searle & Co.
    Inventors: John H. Dygos, Kathleen T. McLaughlin, John S. Ng, Kalidas Paul
  • Patent number: 4255597
    Abstract: There is disclosed a process for the production of hexachlorocyclopentadiene comprising the steps of:1. Reacting liquid cyclopentadiene and chlorine at a temperature of from about 0.degree. to about 100.degree. C. until an average of at least 4 chlorine atoms has been added per mole of cyclopentadiene to form a first-stage product;2. heating the resultant liquid reaction product of Step 1 in a second stage at a temperature of from about 140.degree. C. to below about 200.degree. C. with chlorine in the presence of from about 0.0001% to about 5.0% (by weight) of an aromatic compound until the reaction products of Step 1 contain an average of about 6 chlorine atoms per molecule, based on cyclopentadiene starting material; wherein said aromatic compound contains from 1 to 3 aromatic rings; at least one of the rings containing a nitrogen atom;3. vaporizing and heating the resulting reaction products of Step 2 in a third stage in the presence of chlorine to a temperature of above 450.degree. C.
    Type: Grant
    Filed: April 18, 1980
    Date of Patent: March 10, 1981
    Assignee: Velsicol Chemical Corporation
    Inventors: Kalidas Paul, Glendon D. Kyker
  • Patent number: 4246205
    Abstract: There is disclosed a process for the production of hexachlorocyclopentadiene comprising the steps of:1. Reacting liquid cyclopentadiene and chlorine at a temperature of from about 0.degree. to about 100.degree. C. until an average of at least 4 chlorine atoms has been added per mole of cyclopentadiene to form a first-stage product;2. heating the resultant liquid reaction product of Step 1 in a second stage at a temperature of from about 140.degree. C. to below about 200.degree. C. with chlorine in the presence of from about 0.0001% to about 5.0% (by weight) of an aromatic compound until the reaction products of Step 1 contain an average of about 6 chlorine atoms per molecule, based on cyclopentadiene starting material; wherein said aromatic compound contains from about 4 to about 30 carbon atoms and from 1 to about 4 aromatic rings; and3. vaporizing and heating the resulting reaction products of Step 2 in a third stage in the presence of chlorine to a temperature of above 450.degree. C.
    Type: Grant
    Filed: September 20, 1979
    Date of Patent: January 20, 1981
    Assignee: Velsicol Chemical Corporation
    Inventors: Kalidas Paul, Glendon D. Kyker
  • Patent number: 4233251
    Abstract: There is disclosed a process for the production of hexachlorocyclopentadiene comprising the steps of:(a) reacting liquid cyclopentadiene and chlorine at a temperature of from about 0 to about 100 degrees centigrade until a minimum of four chlorine atoms has been added per mole of cyclopentadiene to form a first-stage product;(b) heating the resultant liquid reaction product of step (a) in a second stage at a temperature of from about 140 degrees centigrade to below about 200 degrees centigrade with chlorine in the presence of from about 0.0001 percent to about 5.0 percent (by weight) of a phosphorus compound until the reaction products of step (a) contain an average of about six chlorine atoms per molecule, based on cyclopentadiene starting material, wherein said phosphorus compound is ##STR1## wherein a, b, c, d, e, f, and g are integers independently selected from the group consisting of 0 and 1, and R.sup.1, R.sup.2, and R.sup.
    Type: Grant
    Filed: June 18, 1979
    Date of Patent: November 11, 1980
    Assignee: Velsicol Chemical Corporation
    Inventors: Glendon D. Kyker, Kalidas Paul