- Attrition-enhanced deracemization and absolute asymmetric synthesis of flavanones from prochiral precursors
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Seven racemic 5,7-dimethoxyflavanones afforded conglomerate crystals upon recrystallization from a solvent. Three methodologies were investigated to achieve asymmetric transformation based on dynamic crystallization of the chiral conglomerate system. The first was chiral symmetry breaking of racemic flavanones by attrition-enhanced deracemization. Continuous suspension of racemic flavanones in a small amount of propanol in the presence of a base (1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)) and glass beads promoted chiral symmetry breaking and converted the flavanones to crystals of (+)- or (-)-enantiomers with 78 to 99% ee. The second method involved cyclization of the intermediate aldol product to give optically active flavanone with 90% ee involving a reversible oxa-Michael addition reaction with attrition-enhanced deracemization. The third was a reaction starting from prochiral 2-hydroxy-4,6-dimethoxyacetophenone and 2-naphthaldehyde under basic conditions, which gave the corresponding flavanone in 89% ee.
- Kasashima, Yoshio,Mino, Takashi,Sakamoto, Masami,Shimizu, Waku,Uemura, Naohiro,Yoshida, Yasushi
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p. 5676 - 5681
(2020/10/13)
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- Synthesis of ochnaflavone and its inhibitory activity on PGE2 production
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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 PGE2 production. Total synthesis was accompl
- Kim, Sung Soo,Van Vo, Anh,Park, Haeil
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p. 3219 - 3223
(2015/04/22)
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- A one-pot synthesis of aurones from substituted acetophenones and benzaldehydes: A concise synthesis of aureusidin
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A one-pot synthesis of aurones from substituted acetophenone and benzaldehyde has been developed on the basis of an improved Algar-Flynn-Oyamada reaction. By using this method, several aurones were prepared in three steps from commercial starting materials. The usefulness of this one-pot strategy was confirmed by a synthesis of aureusidin, an inhibitor of iodothyronine deiodinase, in 41% overall yield. In comparison with a two-step synthesis of this product from the same substrates, the one-pot strategy was more effective, giving a higher yield and requiring fewer and simpler operations. Georg Thieme Verlag Stuttgart New York.
- Zhao, Xiaolong,Liu, Jie,Xie, Zhixiang,Li, Ying
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p. 2217 - 2224
(2012/09/22)
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- Structure - Activity relationship studies of chalcone leading to 3-hydroxy-4,3′,4′,5′-tetramethoxychalcone and its analogues as potent nuclear factor κB inhibitors and their anticancer activities
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Chalcone is a privileged structure, demonstrating promising anti-inflammatory and anticancer activities. One potential mechanism is to suppress nuclear factor kappa B (NF-κB) activation. The structures of chalcone-based NF-κB inhibitors vary significantly that there is minimum information about their structure-activity relationships (SAR). This study aims to establish SAR of chalcone-based compounds to NF-κB inhibition, to explore the feasibility of developing simple chalcone-based potent NF-κB inhibitors, and to evaluate their anticancer activities. Three series of chalcones were synthesized in one to three steps with the key step being aldol condensation. These candidates demonstrated a wide range of NF-κB inhibitory activities, some of low micromolar potency, establishing that structural complexity is not required for NF-κB inhibition. Lead compounds also demonstrate potent cytotoxicity against lung cancer cells. Their cytotoxicities correlate moderately well with their NF-κB inhibitory activities, suggesting that suppressing NF-κB activation is likely responsible for at least some of the cytotoxicities. One lead compound effectively inhibits lung tumor growth with no signs of adverse side effects.
- Srinivasan, Balasubramanian,Johnson, Thomas E.,Lad, Rahul,Xing, Chengguo
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experimental part
p. 7228 - 7235
(2010/08/19)
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