Heterocyclic compounds. Part IX. Coumarins from substituted resacetophenones and ethyl aceto-acetate

Abstract

The condensation of acetoacetic ester with substituted resacetophenones in the presence of phosphorus oxychloride has been studied. Ethylresacetophenone, orcacetophenone, respropiophenone, resbutyrophenone, 4-benzoylresorcinol, and gallacetophenone underwent the desired condensations giving the derivatives of 7-hydroxy-4-methylcoumarins. Negative results were obtained with bromoresacetophenone, methyl, β-resacetophenone carboxylate, 2:4-diacetylresorcinol, 4:6-diacetylresorcinol, 4-acetyl-α-naphthol, 4-propionyl-α-naphthol, and 4-butyryl-α-naphthol. We have also studied the condensation of methyl 2:4-dihydroxy-5-ethylbenzoate with acetic ester for the synthesis of 5-hydroxy-8-ethyl-4-methylcoumarin. An explanation on the electronic conception has been offered regarding the capacity of phenols and their substitution products to undergo the Pechmann Reaction.