Nuclear oxidation in flavones and related compounds

Summary

The most important example of ortho-oxidation from the point of view of the biogenesis of the anthoxanthins is the conversion of quercetin into myricetin.O-3∶5∶7∶3′-Tetramethyl quercetin has now been oxidised toO-tetramethyl-myricetin by the two stage process already explored in Part XV. The intermediate O-tetramethyl quercetin aldehyde and the final myricetin tetramethyl ether are obtained in satisfactory yields. From the latter 5-methoxykanugin, hexamethyl myricetin and myricetin have been obtained. These experiments could be taken as support for the multi-stage mechanism of ortho-oxidation. The appropriateness of the reagents from the point of view of biogenesis is discussed.