Patents by Inventor Heshang Zhang

Heshang Zhang 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 preparing Donepezil and its derivatives
    Patent number: 8318942
    Abstract: A process for producing a Donepezil derivative represented by the formula (I), wherein R1, R2, R3, and R4 each independently represents H, F, an alkyl having from 1 to 4 carbon atoms, or an alkoxy having from 1 to 4 carbon atoms; R5 represents a phenyl or a substituted phenyl; and n is an integer from 0 to 2, characterized in that the process comprises: (a) a reaction of 4-pyridinecarboxaldehyde with a compound of formula (II) in the presence of a strong acid HX to form a compound of formula (III); (b) a catalytic hydrogenation of a compound of formula (III) or a compound of formula (V) to yield a compound of formula (IV); and (c) an alkylation reaction of a compound of formula (IV) to yield a compound of formula (I).
    Type: Grant
    Filed: October 28, 2004
    Date of Patent: November 27, 2012
    Assignee: Tianjin Hemay Bio-Tech Co., Ltd.
    Inventor: Heshang Zhang