Patents by Inventor Theodor Siegfried

Theodor Siegfried 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).

  • Method for the production of (3-alkoxycarbonyl-2-butenyl) triphenylphosphonium salts
    Patent number: 5777149
    Abstract: Novel processes and intermediates useful for the manufacture of the Wittig ester salts are disclosed. The Wittig ester salts are known as important C.sub.5 building blocks for the manufacture of various polyenecarboxylic acid esters in the field of carotenoid chemistry.
    Type: Grant
    Filed: June 13, 1997
    Date of Patent: July 7, 1998
    Assignee: Roche Vitamins Inc.
    Inventors: Bruno Burdet, August Ruttimann, Jean-Marie Santer, Theodor Siegfried
  • Method for the production of (3-alkoxycarbonyl-2-butenyl) triphenylphosphonium salts
    Patent number: 5681977
    Abstract: Novel processes and intermediates useful for the manufacture of the Wittig ester salts are disclosed. The Wittig ester salts are known as important C.sub.5 building blocks for the manufacture of various polyenecarboxylic acid esters in the field of carotenoid chemistry.
    Type: Grant
    Filed: January 7, 1997
    Date of Patent: October 28, 1997
    Assignee: Roche Vitamins Inc.
    Inventors: Bruno Burdet, August Ruttimann, Jean-Marie Santer, Theodor Siegfried
  • Method for the production of (3-alkoxycarbonyl-2-butenyl) triphenylphosphonium salts
    Patent number: 5631398
    Abstract: A processes and intermediates useful for the manufacture of the Wittig ester salts are disclosed. The Wittig ester salts are known as important C.sub.5 building blocks for the manufacture of various polyenecarboxylic acid esters in the field of carotenoid chemistry.
    Type: Grant
    Filed: November 16, 1995
    Date of Patent: May 20, 1997
    Assignee: Roche Vitamins Inc.
    Inventors: Bruno Burdet, August R uttimann, Jean-Marie Santer, Theodor Siegfried
  • Process for the enantioselective hydrogenation of ketosiophorone derivatives
    Patent number: 5543559
    Abstract: The present invention is concerned with a process for the manufacture of optically active compounds of the formula ##STR1## wherein R signifies lower alkyl, lower alkoxy, phenyl, benzyl or --NR.sub.2.sup.1, R.sup.1 signifies lower alkyl, phenyl, benzyl or hydrogen and * signifies an optically active center, by asymmetrically hydrogenating an enol derivative of ketoisophorone of the formula ##STR2## wherein R has the significance given above, in the presence of a rhodium complex of an optically active diphosphine ligand.
    Type: Grant
    Filed: June 8, 1995
    Date of Patent: August 6, 1996
    Assignee: Hoffman-La Roche Inc.
    Inventors: Emil A. Broger, Yvo Crameri, Rudolf Schmid, Theodor Siegfried
  • Method for the production of (3-alkoxycarbonyl-2-butenyl)triphenylphosphonium salts
    Patent number: 5502236
    Abstract: Novel processes and intermediates useful for the manufacture of the Wittig ester salts are disclosed. The Wittig ester salts are known as important CS building blocks for the manufacture of various polyenecarboxylic acid esters in the field of carotenoid chemistry.
    Type: Grant
    Filed: March 17, 1995
    Date of Patent: March 26, 1996
    Assignee: Hoffmann-La Roche Inc.
    Inventors: Bruno Burdet, August Ru/ ttimann, Jean-Marie Santer, Theodor Siegfried
  • Rearrangement process
    Patent number: 5041563
    Abstract: A process for the manufacture of ascorbic acid from 2-ketogulonic acid esters (KGAE) utilizing amine salts of the latter is disclosed.
    Type: Grant
    Filed: May 22, 1990
    Date of Patent: August 20, 1991
    Assignee: Hoffman-La Roche Inc.
    Inventors: Peter Fahrni, Theodor Siegfried