- Microbial conjugation studies of licochalcones and xanthohumol
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Microbial conjugation studies of licochalcones (1–4) and xanthohumol (5) were performed by using the fungi Mucor hiemalis and Absidia coerulea. As a result, one new glucosylated metabolite was produced by M. hiemalis whereas four new and three known sulfated metabolites were obtained by transformation with A. coerulea. Chemical structures of all the metabolites were elucidated on the basis of 1D-, 2D-NMR and mass spectroscopic data analyses. These results could contribute to a better understanding of the metabolic fates of licochalcones and xanthohumol in mammalian systems. Although licochalcone A 4′-sulfate (7) showed less cytotoxic activity against human cancer cell lines compared to its substrate licochalcone A, its activity was fairly retained with the IC50 values in the range of 27.35–43.07 μM.
- Han, Fubo,Xiao, Yina,Lee, Ik-Soo
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- Synthetic method for licochalcone C
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According to the present invention, licochalcone C is produced by performing C-prenylation using A_2O_3, position selective deprotection and methylation, and general Claisen-Schmidt condensation under a base condition. A [3,3]-sigma bond position transferring reaction promoted by water cannot be applied to licochalcone C synthesis due to a decomposition problem. According to the present invention, it has been confirmed that position selective C-prenylation using Al_2O_3 is a novel method for synthesizing licochalcone C.COPYRIGHT KIPO 2015
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Page/Page column 10
(2016/10/09)
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- Concise synthesis of licochalcone a through water-accelerated [3,3]-sigmatropic rearrangement of an aryl prenyl ether
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Claisen-Schmidt condensation of 4-(tetrahydropyran-2-yloxy)acetophenone with 2-methoxy-4-[(3-methylbut-2-en-1-yl)oxy]benzaldehyde gave a THP-protected chalcone ether. Removal of the THP group under mild acidic conditions gave the corresponding chalcone ether, which underwent a water-accelerated Claisen rearrangement under microwave irradiation or heating in a sealed tube in aqueous ethanol to give a good yield of licochalcone A, which has diverse biological activities; no product of deprenylation or abnormal Claisen rearrangement was formed. The abnormal Claisen rearrangement of -substituted allyl aryl ethers is known to be a problem in [3,3]-sigmatropic rearrangement reaction; this, however, was not detected in our water-accelerated system.
- Jeon, Jae-Ho,Kim, Mi Ran,Jun, Jong-Gab
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experimental part
p. 370 - 376
(2011/04/22)
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- Synthesis of licochalkone-A
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Claisen rearrangement of 4'-hydroxy-2-methoxy-4-prenyloxychalkone (III) using acetic anhydride in dimethylaniline yields four compounds, viz. 4'-acetoxy-2-methoxy-4'',4'',5''-trimethyldihydrofuranochalkone (IV), 4,4'-diacetoxy-2-methoxy-5-(α,α-dimethylallyl)chalkone (V), 4,4'-diacetoxy-2-methoxy-3-(α,α-dimethylallyl)chalkone (VI) and 4,4'-diacetoxy-2-methoxychalkone (VII).Mild alkaline hydrolysis of V affords 4,4'-dihydroxy-2-methoxy-5-(α,α-dimethylallyl)chalkone (VIII, licochalkone-A).
- Islam, Azizul,Hossain, M Amzad
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p. 713 - 715
(2007/10/02)
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- Synthesis of Licochalcone-A
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4,4'-Dihydroxy-2-methoxy-5-(α,α-dimethylallyl)chalcone (VII) (licochalcone-A) has been synthesised starting from β-resorcylaldehyde which on partial O-prenylation followed by methylation affords the aldehyde (II).The aldehyde (II) on condensation with p-methoxymethoxyacetophenone (III) under alkaline conditions affords the chalcone (IV), which on Claisen rearrangement yields the chalcone (V).Deacetylation and then demethoxymethylation of V by methanolic HCl affords licochalcone-A (VII), identical with a natural sample.
- Khan, Saeed Ahmad,Krishnamurti, M.
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p. 276 - 277
(2007/10/02)
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