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:
May. 31, 1988
Filed:
May. 03, 1985
Applicant:
Inventors:
Assignee:
Ciba-Geigy Corporation, Ardsley, NY (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07D / ; C07D / ; C07D / ; C07D / ;
U.S. Cl.
CPC ...
544313 ; 546113 ; 546116 ; 546193 ; 546194 ; 546281 ; 546291 ; 546296 ; 546297 ; 546299 ; 546306 ; 546316 ; 546321 ; 546250 ;
Abstract
The invention relates to a process for the preparation of pyridine-2,3-dicarboxylic acid derivatives of formula ##STR1## which process comprises reacting a hydrazone of formula II ##STR2## with a maleic acid derivative of formula III ##STR3## to give a 1-amino-1,4-dihydropyridine-2,3-dicarboxylic acid derivative of formula IV ##STR4## and subsequently removing R.sub.9 R.sub.10 NH. In the above formulae, R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.9, R.sub.10 and X are as defined in claim 1. The pyridine-2,3-dicarboxylic acid derivatives of formula I are intermediates for the preparation of herbicidal compounds.