Synthesis of diphenyl-substituted flavonoid compounds on both benzene rings.

Condensation of o-hydroxyacetophenone and its 3- and 5-phenyl-substituted compounds with 2- or 4-methoxy-biphenyl-3-carbaldehyde gave six mono- and diphenyl-substituted 2′-hydroxychalcones (5a–f), which were cyclized with alkali to afford the flavanones. The chalcones 5a–f were also converted to the corresponding flavones via chalcone bromides.