An Efficient Synthesis of Chrysin

Two routes for the synthesis of the flavones chrysin are described. In the first 1,3,5-trimethoxybenzene was converted to 2-hydroxy-4,6-dimethoxyacetophenone and then by condensation with benzaldehyde to 2′-hydroxy-4′,6′-dimethoxychalcone. The latter was cyclised with iodine and demethylated with pyridine hydrochloride to form chrysin in 53% overall yield. In the second route, 1,3,5-trimethoxybenzene was acylated with cinnamic acid to form the chalcone which was then converted to chrysin in 30.7% overall yield.