Nuclear oxidation in the flavone series. Part VIII. 7 : 8-Dihydroxy-flavone and-flavonol

The possibility of orthor nuclear oxidation in the flavone series has been tested using 7-hydroxy-flavone and 3-methoxy-7-hydroxyl-flavone. By means of alkaline persulphate 7 : 8-dihydroxy-flavone (10% yield) and 3-methoxy-7 : 8-dihydroxy-flavone (20% yield) could be obtained. This seems to offer an easier method of preparing the flavonol, 3 : 7 : 8-trihydroxy flavone. The intermediate stage of the sulphate could be isolated pure from 7-hydroxyflavone