Novel 4-Aroyl-3-alkoxy-2(5H)-furanones as Precursors for the Preparation of Furo[3,4-b][1,4]-diazepine Ring System

A general synthesis of tetronic acid derivatives, namely 4-aroyl-3-alkoxy-2(5H)-furanones, is achieved via the treatment of an anhydrous dimethylformamide (DMF) solution of 4-aroyl-3-hydroxy-2(5H)-furanones with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as base at -10-0°C, followed by the addition of alkyl iodide. Their structural assignments are based on spectroscopic data and confirmed by X-ray crystallography. These furanones were used as starting materials for the preparation of furodiazepines.