Synthetic studies on the construction of 7-O-methylquercetin through regioselective protection and alkylation of quercetin

Synthetic studies on the construction of 7-O-methylquercetin from quercetin in 36% yield in four steps is reported, this strategy relies on one hand on the selective protection of the catechol group with dichlorodiphenylmethane using dephenyl ether as a solvent, on the other hand, on the selective protection of the 3-hydroxyl group with benzyl bromide, these two different protecting groups can be removed under the same hydrogenation.