Formylation of 5-hydroxybenzofuran derivatives and synthesis of furo-[3,2-f]coumarins based on them*
The formylation of esters of 5-hydroxy-1-benzofuran-3-carboxylic acid has been studied. The interaction of the synthesized aldehydes with esters of β-keto acids and hetarylacetonitriles gave furo[3,2-f]coumarin-1-carboxylic acids derivatives.