Patents by Inventor Stephen E. French

Stephen E. French 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 1-aryl-3-amino-5-pyrazolones
    Patent number: 4281143
    Abstract: Disclosed is a process for the preparation of certain 1-aryl-3-amino-5-pyrazolones by reacting a 3-nitropropionic acid ester with certain aryldiazonium salts to produce intermediate .alpha.-nitrohydrazones and then reducing the intermediate to give the corresponding aminopyrazolones. The aryl group may be, for example, phenyl, 4-methoxyphenyl, or the like, the diazo anion can be, e.g., Br.sup.-, Cl.sup.-, BF.sub.4.sup.-, or SO.sub.4.sup..dbd., and the ester alcohol moiety can be any convenient, unreactive group, preferably alkyl. The aminopyrazolones are useful for the preparation of photographic couplers.
    Type: Grant
    Filed: September 4, 1979
    Date of Patent: July 28, 1981
    Assignee: Eastman Kodak Company
    Inventors: John A. Hyatt, Stephen E. French, Cataldo A. Maggiulli