• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3219-3223
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• 2014

Ochnaflavone, a naturally occurring biflavonoid composed of two units of apigenin (5,7,4'-trihydroxyflavone) joined via a C-O-C linkage, was first synthesized and evaluated its inhibitory activity on $PGE_2$ production. Total synthesis was accomplished through modified Ullmann diaryl ether formation as a key step. Coupling reactions of 4'-halogenoflavones and 3'-hydroxy-5,7,4'-trimethoxyflavone were explored in diverse reaction conditions. The reaction of 4'-fluoro-5,7-dimethoxyflavone (2c) and 3'-hydroxy-5,7,4'-trimethoxyflavone (2d) in N,N-dimethylacetamide gave the coupled compound 3 in 58% yield. Synthetic ochnaflavone strongly inhibited PGE2 production ($IC_{50}=1.08{\mu}M$) from LPS-activated RAW 264.7 cells, which was due to reduced expression of COX-2. On the contrary, the inhibition mechanism of wogonin was somewhat different from that of ochnaflavone although wogonin, a natural occurring anti-inflammatory flavonoid, showed strong inhibitory activity of $PGE_2$ production ($IC_{50}=0.52{\mu}M$), and seems to be COX-2 enzyme inhibition. Our concise total synthesis of ochnaflavone enable us to provide sufficient quantities of material for advanced biological studies as well as to efficiently prepare derivatives for structure-activity relationship study.

• YAKHAK HOEJI
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• v.54 no.3
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• pp.200-204
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• 2010

Nuclear factor-${\kappa}B$ (NF-${\kappa}B$) plays critical roles in physiological and pathological processes such as immune function, cellular growth, homeostasis, apoptosis, and inflammation. As part of our ongoing efforts to develop novel NF-${\kappa}B$ inhibitory agents, we reported that KL-1156 (6-hydroxy-7-methoxychroman-2-carboxylic acid phenylamide) exhibited potent inhibitory activity of NF-${\kappa}B$. For further structure-activity relationship, a series of 7-aryloxy-chroman-2-carboxylamide derivatives were synthesized to explore their inhibitory activities of NF-${\kappa}B$.

• Bulletin of the Korean Chemical Society
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• v.28 no.9
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• pp.1601-1604
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• 2007