Patents by Inventor Yifeng Nian

Yifeng Nian 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).

  • Publication number: 20060148866
    Abstract: A novel process is provided for producing pramipexole base or its optical isomeric mixture as defined hereinabove i.e. (R,S)-2-amino-6-propyl-4,5,6,7-tetrahydrobenzothiazole avoiding the use of borane tetrahydrofuran complex and using a more convenient reducing agent like sodium triacetoxyborohydride instead. The provided process comprises reacting the starting material (S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole or its optical isomeric mixture as defined hereinabove i.e. (R,S)-2,6-diamino-4,5,6,7-tetrahydrobenzothiazole with propionaldehyde in an organic solvent to obtain the respective enamine, which is subsequently reduced in situ, optionally without isolation, to obtain pramipexole or its optical isomeric mixture as defined hereinabove i.e. (R,S)-2-amino-6-propyl-4,5,6,7-tetrahydrobenzothiazole, and the acid addition salts thereof.
    Type: Application
    Filed: December 13, 2005
    Publication date: July 6, 2006
    Applicant: Chemagis Ltd.
    Inventors: Guangxin Xia, Yifeng Nian, Tiema Yan, Jin Suo, Michael Brand, Oded Arad