It is shown that the nuclear oxidation of hydroxy-chalkones can be successfully effected thereby introducing a fresh hydroxyl in the 5-position which corresponds to the 6-position in flavanones and flavones. 2-Hydroxy-4-methoxy-chalkone and 2-hydroxy-4∶6-dimethoxy-chalkone have thus been oxidised to the 2∶5-dihydroxy compounds. In the first case the product is shown to be 2∶5-dihydroxy-4-methoxy-chalkone by complete methylation and identification of the derivative as 2∶4∶5-trimethoxy-chalkone. In the second case it is proved to be 2∶5-dihydroxy-4∶6-dimethoxy-chalkone by partial methylation and conversion into 5∶6∶7-trimethoxy-flavanone.