Patents by Inventor Wanda I. Tormos

Wanda I. Tormos 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).

  • Asymmetric process for preparing florfenicol, thiamphenicol chloramphenicol and oxazoline intermediates
    Patent number: 5352832
    Abstract: The present invention comprises a process for the asymmetric synthesis of florfenicol, thiamphenicol or chloramphenicol, from a derivative of trans-cinnamic acid, comprising the steps:(a) converting the acid to an acid chloride using a chlorinating agent, and reducing the acid chloride to a trans allylic alcohol with a reducing agent;(b) asymmetrically epoxidizing the allylic alcohol of step (a), by reacting with t-butylhydroperoxide in the presence of a chiral epoxidation catalyst prepared from titanium (IV) isopropoxide and L-diisopropyltartaric acid, to form a chiral epoxide;(c) regioselectively opening the epoxide of step (b) by sequentially treating with sodium hydride, zinc chloride and dichloroacetonitrile to form an oxazoline;(d) stereoselective inversion/isomerization of the oxazoline of step (c) by sequentially treating with: (i) a lower alkylsulfonyl chloride and a tertiary amine base; (ii) sulfuric acid and water; (iii) an alkali metal hydroxide; to form an oxazoline;(e) optionally treating the ox
    Type: Grant
    Filed: December 18, 1992
    Date of Patent: October 4, 1994
    Assignee: Schering Corporation
    Inventors: Guang-Zhong Wu, Wanda I. Tormos