• YAKHAK HOEJI
• /
• v.38 no.1
• /
• pp.1-5
• /
• 1994

We have synthesized some 2-(2-benzyloxybenzoyloxy)-and 2-(2,6-dibenzyloxybenzoyloxy)-acetophenones as intermediates for flavone synthesis. The reaction of polyoxygenated 2-hydroxyacetophenones with 2-benzyloxybenzoic acid or 2,6-dibenzyloxybenzoic acid in the presence of dicyclohexylcarbodiimide and p-dimethylaminopyridine resulted in a good yield$(70{\sim}89%)$ of 2-(2-benzyloxybenzoyloxy)-acetophenones or 2-(2,6-dibenzyloxybenzoyloxy) acetophenones under milder conditions and in shorter time than the previous methods. This new methods using benzoic acids instead of benzoyl chlorides saves one reaction step of acid chlorination in comparision of the previous methods.

• YAKHAK HOEJI
• /
• v.50 no.6
• /
• pp.398-402
• /
• 2006

Flavone was found to inhibit tyrosinase and reduce synthesis of melanin to show skin-lightening effect. With the hope of identifying skin-lightening flavones, we synthesized flavone analogs. Substituted benzoic acids (1) were treated with oxalyl chloride in DMF to yield benzoyl chlorides (2), which were reacted with 2-hydroxyacetophenones (3) to afford 2-benzoyloxyacetophenones (4). These acetophenones (4) were converted into 1,3-diketones (5) with base and then treated with acid to give flavone derivatives (6).

• Archives of Pharmacal Research
• /
• v.17 no.6
• /
• pp.434-437
• /
• 1994

1-Polyoxyphenyl-3-(2, 6-dioxyphenyl)propane-1, 3-diones have been synthesized as intermediates for flavone synthesis by condensation of 2-(2, 6-dioxybenzoyloxy)polyoxyacetophenone in the presence of phae transfer catalyst. The average yields of 1-polyoxyphenyl-3-phenylpropane-1, 3-diones, 1-polyoxyphenyl-3(2-benzyloxyphenyl)propane-1, 3-diones and 1-polyoxy-3-(2, 6-dibenzyloxyphenyl)propane-1, 3-dions were 79%, 74% and 71% respectively. The bulkiness of the benzyloxy groups or methyoxy gorups exerted steric hindrance and reduced the yield. Nevertheless, the yield were higher than the previously reported ones.

• KSBB Journal
• /
• v.13 no.3
• /
• pp.251-258
• /
• 1998

A structured kinetic model is proposed to describe cell growth and secondary metabolite, flavone glycosides, synthesis in batch suspension culture of Scutellaria baicalensis G. The model has been developed by representing the physiological state of cell described as the activity and viability which can be estimated based on the culture fluorescence. In the model, three type of cells are considered; active-viable, nonactive-viable and dead cells. Viable cell weight could be determined based on the relative fluorescence intensity. The flavone glycosides could be produced by both active-viable and non-active viable cells with a different production rate. And the model includes the cell expansion due to glucose concentration and death phase which accounts for the release of intracellular secondary metabolite into medium. Dependent variables include substrate concentration(glucose), cell mass(dry cell weight and fresh cell weight), product concentration(flavone glycosides), activity and viability. Satisfactory agreement between the model and experimental data is obtained from shake flask culture of Scutellaria baicalensis G. The proposed model can predict the cell growth and flavone glycosides synthesis as well as intermediate materials.

• KSBB Journal
• /
• v.13 no.3
• /
• pp.259-267
• /
• 1998

Optimal feeding strategies in bioreactor operation of Scutellaria baicalensis G. plant cell culture were investigated to maximize the production of flavone glycosides by using a structured kinetic model which can predict culture growth and flavone glycosides synthesis in a rigorous, quantitative manner. For the production of baicalin and wogonin-7-0-GA, the strategies for glucose feeding into Scutellaria baicalensis G. plant cell culture were proposed based on the model, which are a periodic fed-batch operation with maintenance of cell viability and of specific production rate respectively, and a perfusion operation with maintenance of specific production rate for baicalin and wogonin-7-0-GA. Simulation results showed that the highest volumetric concentration of flavone glycosides was obtained in a periodic fed-batch operation with maintenance of cell viability among all the suggested strategies. In the periodic fed-batch operations, the higher volumetric production of flavone glycosides was achieved compared with that in the perfusion operation. It can be concluded that a periodic fed-batch operation with maintenance of cell viability would be the optimal and practical operating strategy of Scutellaris baicalensis G. plant cell culture for the production of flavone glycosides.

• Journal of Applied Biological Chemistry
• /
• v.50 no.2
• /
• pp.85-87
• /
• 2007

To establish the synthetic method for dihydrochalcones as an important bioactive compounds, 2'-hydroxydihydrochalcone has been synthesized from the reduction of flavone in 20% yield. Flavone with five equivalents of ammonium formate in the presence of Pd/C in methanol under $N_2$ atmosphere produced the C-ring opened product. It was characterized by UV-VIS, ESI-MS and $^1H-NMR$ spectroscopy, and identified as 2'-hydroxydihydrochalcone.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1993.04a
• /
• pp.40-40
• /
• 1993

2-Benzoyloxyacetophenones were prepared by reaction of benzooic acids and 2-hydroxyacetophenones in the presence of dicyclohexylcarbodiimide and 4-dimethylaminopyridine. The rearrangement of 2-Benzoyloxy acetophenones to 2-Dibenzoylmethans has been carried out in the presence of tetrabutylammoniumfl uoride( a phase transfer catalyst ). Both methods have been applied first for the synthesis of flavones and gave better yields of products and the reaction ran in shorter reaction time.

• Journal of Microbiology and Biotechnology
• /
• v.19 no.5
• /
• pp.491-494
• /
• 2009

Within the secondary metabolite class of flavonoids, which consist of more than 10,000 known structures, flavones define one of the largest subgroups. The diverse function of flavones in plants as well as their various roles in the interaction with other organisms offers many potential applications including in human nutrition and pharmacology. We used two genes, flavone synthase (PFNS-l) that converts naringenin into apigenin and flavone 7-O-methyltransferase (POMT-7) that converts apigenin into 7-O-methyl apigenin, to synthesize 7-O-methyl apigenenin from naringenin. The PFNS-l gene was subcloned into the E. coli expression vector pGEX and POMT-7 was subcloned into the pRSF vector. Since both constructs contain different replication origins and selection markers, they were cotransformed into E. coli. Using E. coli transformants harboring both PFNS-l and POMT-7, naringenin could be converted into 7-O-methyl apigenin, genkwanin.

• Archives of Pharmacal Research
• /
• v.26 no.5
• /
• pp.345-350
• /
• 2003

5,7-Dihydroxyflavones and their Ο-methylated flavone analogs were prepared and evaluated their anti-inflammatory activity to decipher the structure-activity relationships. Most of the analogs were achieved from 2,4,6-trihydroxyacetophenone in 4 steps. 5,7-Dihydroxy-4 -methoxyflavone (4c) and 7-hydroxy-4 ,5-dimethoxyflavone(6c) were prepared following a different synthetic pathway. Among the synthetic flavones tested, 5-hydroxy-7-methoxyflavone analogs (3a-3e) showed moderate inhibitory activities of $PGE_2$ production from LPS-induced RAW 264.7 cells.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.5
• /
• pp.723-724
• /
• 2007