Unsymmetrically Substituted 3,3′-Methylene Bridged 2,2′-Dihydroxychromones

Unsymmetrically substituted dicoumarol derivatives have been synthesized by taking advantage of the fact that 4-hydroxycoumarins will undergo the Mannich reaction at C3 and also take part in Michael-type addition reactions. In the presence of methyl iodide, 4-hydroxy-3-N-piperidinomethylcoumarin and 4-hydroxycoumarin gave dicoumarol. By using monosubstituted 4-hydroxycoumarins a variety of unsymmetrically substituted dicoumarols have been prepared in good yield. The infrared spectra of some of the intermediates and products are reported and discussed.