Process for the preparation of 1-hydroxy-2-pyridones

摘要

The invention relates to a process for the preparation of 1-hydroxy-2-pyridones of the formula I <IMAGE> (I) by reaction of a pyrone of the formula II <IMAGE> (II) 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 R1 and R2 in the formulae I and II are described herein.