Partial demethylation of 2-hydroxy-4 ∶ 6-dimethoxy chalkone with aluminium chloride yields 2 ∶ 4-dihydroxy-6-methoxychalkone which could be cyclised to 5-methoxy-7-hydroxy-flavanone. The use of hydrobromic acid for the demethylation produces directly 5-hydroxy-7-methoxy flavanone due to initial ring closure and subsequent demethylation in the 5-position of the flavanone. When this reagent acts on 2-hydroxy-4 ∶ 6 ∶ 4′-trimethoxy chalkone sakuranetin, the naturally occurring monomethyl ether of naringenin is produced.