ChemInform Abstract: Darzens Reaction of 2‐Bromo‐4,6‐dimethoxy‐3(2H)‐benzofuranone with Aromatic Aldehydes to Form Flavonoids.

Abstract

2008 Benzopyran derivatives R 0350Darzens Reaction of 2-Bromo-4,6-dimethoxy-3(2H)-benzofuranone with Aromatic Aldehydes to Form Flavonoids. -The applicability of benzofuranone (I) to form flavanoid-derived epoxides in the course of the reaction with aldehydes (II) is investigated. However, instead of the epoxides flavonols (III) and in certain cases traces of benzofuranyl substituted flavonols such as (IV) are isolated. The generation of (III) is assumed to proceed via ring expansion of the initially formed epoxides. Flavonols (III) can react with further (I) to the 1:2 adducts (IV) as minor products. -(OTTERSBACH, P. A.; BOLEK, D.; LEPICOVA, E.; NIEGER, M.; GUETSCHOW*, M.; J. Heterocycl. Chem. 45 (2008) 4, 1149-1153; Inst. Pharm., Rhein. Friedrich-Wilhelms-Univ., D-53121 Bonn, Germany; Eng.) -M. Paetzel 46-137