Title of Invention

A METHOD FOR THE IN-SITU REMOVAL OF IMPURITIES FROM A SAPONIFIED SOLUTION OF PYRIDINE-2,3-DICARBOXYLIC ACID ESTER

Abstract A method for the in-situ treatment of a pyridine-2,3-dicarboxylic acid ester with an oxidizing agent, such as hydrogen peroxide, to improve product quality is provided. The method for the in-situ removal of impurities from a saponified solution of pyridine-2,3-dicarblxylic acid ester comprises the steps of providing a solution of pyridine-2,3-dicarboxylic acid ester, saponifying the solution with a base to form the corresponding pyridine-2,3-dicarboxylic acid salt, reacting the solution with an oxidizing agent in an amount effective to remove impurities, acidifying the solution with an acid to convert the pyridine-2,3-dicarboxylic acid into the corresponding pyridine-2,3-dicarboxylic acid, and collecting a purified solution comprising pyridine-2,3-dicarboxylic acid. Further provided is a method for the preparation of herbicidal 2-(2-imidazolin-2-yl)nicotinic acids, esters, and salts by using a pyridine-2,3-dicarboxylic acid salt prepared by the above method as an intermediate.
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Documents:


Patent Number 242245
Indian Patent Application Number 420/CHENP/2006
PG Journal Number 35/2010
Publication Date 27-Aug-2010
Grant Date 19-Aug-2010
Date of Filing 01-Feb-2006
Name of Patentee BASF AKTIENGESELLSCHAFT
Applicant Address 67056 Ludwigshafen
Inventors:
# Inventor's Name Inventor's Address
1 LEVY, Michael, A. 4106 West Ely Road, Hannibal, MO 63401
PCT International Classification Number C07D 213/803
PCT International Application Number PCT/EP04/06893
PCT International Filing date 2004-06-25
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 60/484,485 2003-07-02 U.S.A.