5-phenylpyridazinones - A serendipitous route from coumarins

Abstract

A new route of the ring transformation has been discovered during the reaction of 4-bromomethylcoumarins with hydrazine hydrate leading to the formation of pharmacologically important pyridazinones in a single step with very high yields. These so obtained pyridazinones have the potential for further functional group interconversions. (C) 2008 Elsevier Ltd. All rights reserved.