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. 26, 1998
Filed:
Nov. 02, 1995
Anuschirwan Peyman, Kelkheim, DE;
Dieter Bernd Reuschling, Butzbach, DE;
Adolf Heinz Linkies, Frankfurt, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
The invention relates to a process for the preparation of 1-hydroxy-2-pyridones of the formula I ##STR1## by reaction of a pyrone of the formula II ##STR2## with a hydroxylammonium salt in the presence of basic compounds, which comprises carrying out the reaction in the presence of a distillable, filterable or extractable acid or a salt thereof in an amount of 0.01 to 20 equivalents with respect to the pyrone of the formula II, and employing as the basic compounds an alkali metal carbonate and/or alkali metal bicarbonate in an amount of 0.8 to 5 equivalents with respect to the hydroxylammonium salt, the radicals R.sup.1 and R.sup.2 in the formulae I and II are described herein.