Synthesis of benzofuro-4-anilino-2H-l-benzopyran-2-one and benzofuro-pyrano -2H-1 -benzopyran-2-one

摘要

The title compounds are synthesized from the corresponding 4-hydroxy-benzopyran-2[H]-ones 5a,b .2,4-Dihydroxy-acetophenone la,b on condensation with 2-bromocyclohexanone,followed by linear cyclisation and then on reaction with diethyl carbonate in presence of pulverised sodium gives 6,7,8,9-tetrahydro-4-hydroxy-benzofuro [3,2-g]-2H--benzopyran-2-one 5a,b,which on reaction with aniline,followed by dehydrogenation with palladised charcoal gives benzo-furo[3,2-g]-4-anilino-2H-l-benzopyran-2-one 7a,b. 5a,b on condensation with benzalacetone followed by dehydrogenation with palladised charcoal furnishes 2-methyl-4-phenyl-4-hydro-pyrano[3,2-c]-benzofuro[3,2-g]-5H-benzopyran-5-one 9a,b.