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:
Apr. 23, 1991
Filed:
Nov. 01, 1989
Dieter Kaufmann, Bergisch Gladbach, DE;
Bernd Gallenkamp, Wuppertal, DE;
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
A new process has been found for the preparation of substituted 2-chloropyridine derivatives of the formula (I) ##STR1## wherein R.sup.1 to R.sup.4 have the meanings as defined in the description. The new process is characterized in that pyridine 1-oxides of the formula II ##STR2## are reacted with a chlorine-containing phosphoric acid derivative from the series of the chlorophosphoric esters and chlorophosphoramides in the presence of an inert organic solvent and in the presence of an acid acceptor at temperatures between -20.degree. C. and 200.degree. C., and the resulting product is separated further, if appropriate. Compound (I) is known as an intermediate product for medicaments (cf.DE-A 2,812,585) or for insecticidel nitromethylene derivatives (cf. EP-A 163,855).