Synthesis and structure of 1-substituted benzopyrano-[4′,3′-c] benzo[3″,4″-f]-2,8-dioxabicyclo[3.3.1]nonane

Abstract

The base catalyzed condensation reaction between 4-hydroxycoumarin and 3-acetylcoumarin (3-benzoylcoumarin) in water at reflux led to the formation of 1-methyl (1-phenyl)-benzopyrano[4′,3′-c]-benzo[3″,4″-f]- 2,8-dioxabicyclo[3.3.1]nonane (2a, b) as final products. When 4-hydroxycoumarin and 3-acetylcoumarin reacted in a glacial acetic acid in the presence of potassium acetate the final product was 7-[3-acetyl-2-oxo-3,4-dihydro-2H-[1] benzopyran-4-yl]methyl-6H,14H,14bH-bis-([1]benzopyrano)[4,3-b:4′, 3′-d]pyran-6,14-dione (4). 4-Hydroxycoumarin and 4-(5-bromo-2- hydroxyphenyl)-3-buten-2-one were condensed in water at reflux and 1-methylcoumarino-[4′,3′-c]-bromobenzo[3″,4″-f]-2, 8-dioxabicyclo[3.3.1]nonane was a final product (3). © 2006 Verlag der Zeitschrift für Naturforschung.