合成路线1

The intermediate acetophenone (III) was prepared from 5-chlorosalicylic acid (I) by O-acetylation with acetic anhydride and a catalytic amount of sulfuric acid, followed by Fries rearrangement of the resulting acetate (II) on heating with aluminum chloride. Condensation of 2-methylquinoline (IV) with an excess of 1,3-benzene dicarboxaldehyde (V) in a refluxing mixture of acetic anhydride and xylene provided aldehyde (VI), which was then condensed with acetophenone (III) by treatment with KOH in a mixture of ethanol and tetrahydrofuran to give chalcone (VII). Finally, oxidative ring closure by refluxing with selenium dioxide in dioxan yielded the desired flavone.