Chromones and Flavones. Part V*. Synthesis of Some 3',3''' and 6,6''-Biflavonyls

The bichaslkonyl derivatives, obtained from the condensation of 2,2'. and 4.4'-dimethoxy-3,3'-diformyl. biphenyla with 2-hydroxyaeetophenon.e and from the condenntion of 4,4'-dihydroxy-3,3'-diacetylbiphenyl with benzaldeb.yile, have been converted into the corresponding biflavonyl derivatives. Some of these have also been obtained by the Ullmann reaction on the appropriate iodnflavones. The Koatanecki-Robinson benzoy­Is tio a of 4,4'-dihydroxy-3,3'-diacetylbiphenyl has been studied. Some of the chalkones have been isomerised to the flavanones