A new alkaline rearrangement of the benzofuran skeleton. One step transformation of 2‐(2‐benzofuranyl)benzonitriles into (Z)‐phenylmethyleneisoindolinones

Abstract

AbstractThe alkaline hydrolysis of 2‐(2‐benzofuranyl)benzonitriles 2 by potassium hydroxide under reflux in ethanol stops at the corresponding amides 5. Using other solvents (ethylene glycol or methoxyethanol) at higher temperatures, one can obtain either the amides 5, the acids 1 or rearrangement products depending on the experimental conditions. The rearrangement products were identified as (Z)phenylmethylenedihydroisoindolinones 6 resulting from opening of the furan ring. The structures of the compounds 6 were established by 1H nmr spectroscopy (nOe) and X‐ray crystallography.