The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 04, 1980
Filed:
Mar. 23, 1979
Applicant:
Inventors:
Michel Soreau, Montmorency, FR;
Yani Christidis, Paris, FR;
Assignee:
Societe Francaise Hoechst, Puteaux, FR;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C07C / ;
U.S. Cl.
CPC ...
562475 ;
Abstract
Demethylation of the 3,4,5-trimethoxybenzoic acid is carried out in the presence of an excess of alkali hydroxide in an amount of ethylene glycol just sufficient to obtain a heterogeneous medium sufficiently fluid in the course of the operation. The ethylene glycol monomethyl ether and the water formed are distilled off progressively with their production and the resulting 4-hydroxy-3,5-dimethoxybenzoic acid is separated by acidification by means of a strong acid and crystallization.