Patents by Inventor Walter Liebenow

Walter Liebenow 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: 4697035
    Abstract: A simplified process for the preparation of basically substituted phenylacetonitriles, in particular of verapamil, is described. This process is carried out with fewer stages and higher yields than the known processes according to the state of the art.
    Type: Grant
    Filed: June 3, 1985
    Date of Patent: September 29, 1987
    Assignee: Ludwig Heumann & Co., GmbH
    Inventors: Lothar Kisielowski, Ingomar Grafe, Walter Liebenow, Kurt H. Ahrens
  • Patent number: 4420488
    Abstract: Quaternary 1,1-diphenyl-4-pyrrolidinium-2-butyne salts corresponding to the following general formula ##STR1## in which R represents methyl or ethyl and X is a chlorine or bromine atom, are described. These compounds are distinguished by improved spasmolytic and broncholytic activity.
    Type: Grant
    Filed: March 13, 1981
    Date of Patent: December 13, 1983
    Assignee: Ludwig Heumann & Co. GmbH
    Inventors: Walter Liebenow, Hans Liedtke
  • Patent number: 4180578
    Abstract: A compound selected from a 2,4-diamino-5-thiobenzylpyrimidine of the formula: ##STR1## in which R is selected from hydrogen, alkyl, lower alkoxy, and halogen and R' is alkyl; and pharmacologically acceptable acid addition salts thereof. These compounds have an anti-bacterial action and are sulphonamide potentiators.
    Type: Grant
    Filed: March 29, 1978
    Date of Patent: December 25, 1979
    Assignee: Ludwig Heumann, & Co. GmbH
    Inventors: Edgar Fritschi, Walter Liebenow, Jaroslav Prikryl
  • Patent number: 4125721
    Abstract: A process for the production of 2,4-diamino-5-(3',4',5'-trimethoxybenzyl)-pyrimidine by condensing trimethoxy benzaldehyde with a substituted propionitrile compound and reacting the condensation product obtained with guanidine, wherein a .beta.-akyl-(aryl-, benzyl-)-oxy-ethyleneoxy-propionitrile corresponding to the formulaR--O--CH.sub.2 --CH.sub.2 --O--CH.sub.2 --CH.sub.2 --CN (I)in which R represents an alkyl group, an optionally substituted phenyl group or a benzyl group, is condensed with trimethoxy benzaldehyde in the presence ofBasic reagents to form a compound corresponding to the general formula ##STR1## in which R is as defined above, and the condensation product (II) obtained is reacted with guanidine in known manner to form 2,4-diamino-5-(3',4',5'-trimethoxybenzyl)-pyrimidine.
    Type: Grant
    Filed: August 1, 1977
    Date of Patent: November 14, 1978
    Assignee: Ludwig Heumann & Co. GmbH
    Inventors: Walter Liebenow, Jaroslav Prikryl