Polymethoxyflavonoids (PMFS) are a class of natural products, which widely exist in citrus plants possessing distinguished anticarcinogenic and antiinflammatory activities. A series of polymethoxyflavonoids and flavonoid glucosides 1a, 1b～4a, 4b, 5～9 have been synthesized via reactions of bromination, methylation, aromatic nucleophilic substitution, Friedel-Crafts acetylation, aldol condensation, cyclization or Algar-Flynn-Oyamada reaction, DDQ dehydrogenation, selective demethylation, glycosidation and deacetylation. The natural products 1a, 1b, 2a, 2b, 3b, 4a, 4b, 5～7, 9 were first total synthesized. Moreover, a new method for the preparation of organic synthetic intermediate 2,3,4,6-tetramethoxyphenol 12 by bromination, metylation and aromatic nucleophilic substitution from resorcinol in high yields was found during synthesizing pentamethoxybenzene 13. The struc-tures of all new compounds have been confirmed by MS, IR, ¹H NMR and ¹³C NMR spectra.

Key words: flavonoids, polymethoxylated flavone, synthesis, bioactivity, 2,3,4,6-trtramethoxyphenol