Mixed Anhydride of Acetic and Formic Acids in the Synthesis of Chromones. 2. Synthesis of 3-Arylchromones

Article abstract of DOI:10.1007/BF00475243

A study was carried out on the reaction of α-substituted 2-hydroxyacetophenones eith the mixed anhydride of acetic and formic acids in the presence of bases of different strength.Chromones containing a conjugated electron-withdrawing substituent at C(3) are formed in close to quantitative yield in the presence of triethylamine.The preparation of chromones containing an unconjugated substituent under these conditions is recommended only for 5-hydroxychromones.