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ChemicalBook CAS DataBase List 5,4''-DIHYDROXY-6,7,8-TRIMETHOXYFLAVONE
16545-23-6

5,4''-DIHYDROXY-6,7,8-TRIMETHOXYFLAVONE synthesis

9synthesis methods
-

Yield: 87%

Reaction Conditions:

Stage #1:4'-benzyloxy-5,6,7,8-tetramethoxyflavone with boron trichloride in dichloromethane;toluene at -78 - 20; for 12 h;Inert atmosphere;
Stage #2: with water;sodium hydroxide in dichloromethane;toluene at 20; for 0.5 h;

Steps:

5.1.1.23. 3',5-Dihydroxy-4',6,7,8-tetramethoxyflavone (17)
General procedure: To a solution of 16 (100 mg, 0.209 mmol) in dichloromethane (5 mL) was added a soln of BCl3 in toluene (1.0 M, 0.42 mL, 0.42 mmol) at -78 °C. The reaction mixture was allowed to warm to rt over a period of 12 h, to which was added 1 M aq. NaOH (10 mL). The mixture was stirred at rt for additional 30 min, acidified with 2 M HCl (10 mL), and extracted with ethyl acetate (2 × 15 mL). The combined organic layer was dried (MgSO4) and concentrated. The residual orange-yellow solids (92 mg) were purified on a silica gel (toluene/ethyl acetate = 3/1) to give 17 (72.0 mg, 0.192 mmol, 92% yield):

References:

Oshitari, Tetsuta;Okuyama, Yuji;Miyata, Yoshiki;Kosano, Hiroshi;Takahashi, Hideyo;Natsugari, Hideaki [Bioorganic and Medicinal Chemistry,2011,vol. 19,# 23,p. 7085 - 7092] Location in patent:experimental part