Synthesis of Benzofurans Modified by Coumarin and Pyrazole Heterocycles

Reactions of 7-hydroxy-2-methyl-8-formylisoflavone with 4-chloromethylcoumarins synthesized 8-(coumarin-4-yl)furo[2,3-h]chromones, which reacted with 2-bromoacetylbenzofuran to produce 8-(benzofuroyl)furo [2,3-h]chromone. Recyclization of the corresponding furochromones through the action of hydrazine hydrate gave 4-hydroxybenzofurans with pyrazole and coumarin or benzofuroyl substituents.