Patents by Inventor Detlef Walther

Detlef Walther 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).

  • Process for the preparation of bendamustine
    Patent number: 8987469
    Abstract: The present invention relates to a method for preparation of alkyl 4-[5-[bis(2 -hydroxyethyl)amino]-1-methyl-1H-benzimidazol-2-yl]butanoate (7) from 2-fluoro-5-nitroaniline, comprising the steps of: (a) conversion of 2-fluoro-5-nitroaniline to 5-(2-fluoro-5-nitroanilino)-5 -oxopentanoic acid (1) using glutaric anhydride, conversion of compound (1) to methylammonium 5-[2-(methylamino)-5-nitroanilino]-5-oxopentanoate (2) using methylamine; conversion of compound (2) to 5[2-(methylamino)-5-nitroanilino]-5-oxopentanoic acid (3) and condensation of compound (3) to 4-(1-methyl-5-nitro-1H-benzimidazol-2-yl)butanoic acid (4); (b) esterification of the product (4) of step a) to alkyl 4-(1-methyl-5-nitro 1H-benzimidazol-2-yl)butanoate (5); (c) reduction of the product of step b) to alkyl 4-(5-amino-l-methyl-1H-benzimidazol-2-yl)butanoate (6), and (d) conversion of the product of step c) to alkyl 4-[5-[bis(2-hydroxyethyl)amino]-1-methyl -1H-benzimidazol-2-yl]butanoate (7).
    Type: Grant
    Filed: July 23, 2013
    Date of Patent: March 24, 2015
    Assignee: Heyl Chemisch-pharmazeutische Fabrik GmbH & Co. KG
    Inventors: Michael Frey, Dirk-Detlef Walther
  • PROCESS FOR THE PREPARATION OF BENDAMUSTINE
    Publication number: 20140031560
    Abstract: The present invention relates to a method for preparation of alkyl 4-[5-[bis(2-hydroxyethyl)amino]-1-methyl-1H-benzimidazol-2-yl]butanoate (7) from 2-fluoro-5-nitroaniline, comprising the steps of: (a) conversion of 2-fluoro-5-nitroaniline to 5-(2-fluoro-5-nitroanilino)-5-oxopentanoic acid (1) using glutaric anhydride, conversion of compound (1) to methylammonium 5-[2-(methylamino)-5-nitroanilino]-5-oxopentanoate (2) using methylamine; conversion of compound (2) to 5-[2-(methylamino)-5-nitroanilino]-5-oxopentanoic acid (3) and condensation of compound (3) to 4-(1-methyl-5-nitro-1H-benzimidazol-2-yl)butanoic acid (4); (b) esterification of the product (4) of step a) to alkyl 4-(1-methyl-5-nitro1H-benzimidazol-2-yl)butanoate (5); (c) reduction of the product of step b) to alkyl 4-(5-amino-1-methyl-1H-benzimidazol-2-yl)butanoate (6), and (d) conversion of the product of step c) to alkyl 4-[5-[bis(2-hydroxyethyl)amino]-1-methyl-1H-benzimidazol-2-yl]butanoate (7)
    Type: Application
    Filed: July 23, 2013
    Publication date: January 30, 2014
    Applicant: Heyl Chemisch-pharmazeutische Fabrik GmbH & Co. KG
    Inventors: Michael Frey, Dirk-Detlef Walther
  • Brushless pump motor with built-in electronic control
    Patent number: 5073736
    Abstract: A motor for a pump, especially a pump for a drum, barrel, or other tanks or containers. The motor has a housing in which a rotor is surrounded by a stator. The motor is an electronically commutated direct current motor that has no brushes. The switch or control device of the motor is an electronic switch or control device that is accommodated in the housing.
    Type: Grant
    Filed: July 7, 1989
    Date of Patent: December 17, 1991
    Assignee: Flux- Gerate GmbH
    Inventors: Alois Gschwender, Detlef Walther, Horst Kruger, Rudiger Pawlischta