- Efficient total synthesis of 5-methoxypsoralen
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A rapid and efficient synthesis of 5-methoxypsoralen, furocoumarin commonly used in dermatology for the treatment by PUVA therapy of skin diseases, is described using cheap and easily available starting materials. An alternative method to synthesize 7-(2-oxoethoxy)coumarin, the key step to generate the furan ring, is suggested. Georg Thieme Verlag Stuttgart.
- Roux, Delphine,Makki, Safwat,Bévalot, Fran?oise,Humbert, Philippe
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- New coumarins from Citrus plants
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Four new coumarins, named peroxytamarin (1), cis-casegravol (5), citrusarin-A (7), and citrusarin-B (8), were isolated from root of Citrus plants and their structures were elucidated by chemical and spectrometric methods. Citrusarin-B (8), a coumarin having both a dimethylpyran ring and a dihydrofuran ring in the molecule, was also synthesized.
- Ito,Fujiwara,Kajita,Ju-ichi,Takemura,Suzuki,Tanaka,Omura,Furukawa
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- Palladium(II)-catalyzed efficient synthesis of wedelolactone and evaluation as potential tyrosinase inhibitor
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Tyrosinase is an enzyme widely distributed in nature, which has multiple functions, especially in the melanin biosynthesis pathway. Despite the few clinically available tyrosinase inhibitors for whitening, a great demand remains for novel compounds with low side effects in terms of potential carcinogenicity and improved clinical efficacy. A natural product, wedelolactone (WEL), with a polyhydroxyl moiety, attracted our attention as a potential tyrosinase inhibitor. Before we studied the biological activity of the natural product, a synthetic methodological research was firstly carried to obtain enough raw material. WEL could be obtained efficiently through palladium-catalyzed boronation/coupling reactions and 2,3-dicyano-5,6-dichlorobenzoquinone (DDQ)-involved oxidative deprotection/annulation reactions. Immediately after, the natural product was proven to be an efficient tyrosinase inhibitor. In conclusion, we developed a mild and efficient approach for the preparation of WEL, and the natural product was disclosed to have anti-tyrosinase activity, which could be widely used in multiple fields.
- Huang, Huidan,Chen, Jianqiu,Ren, Jie,Zhang, Chaofeng,Ji, Fei
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- Total synthesis of demethylwedelolactone and wedelolactone by Cu-mediated/Pd(0)-catalysis and oxidative-cyclization
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Hedysarimcoumestan B, which can be isolated from Chinese herbal medicine, is achieved, in which the longest linear sequence is only eight steps, in 50% overall yield from commercially available phloroglucinol. The key transformations in the synthesis are Cu-mediated/Pd(0)-catalysis and I2/pyridine oxidative-cyclization reactions. This synthetic strategy can be applied to give access to the demethylwedelolactone (4) and wedelolactone (5), which were afforded from commercially available phloroglucinol in high 38 and 33% yields, respectively.
- Chang, Chia-Fu,Yang, Ling-Yi,Chang, Shiao-Wei,Fang, Yu-Ting,Lee, Yean-Jang
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p. 3661 - 3666
(2008/09/20)
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- Natural and synthetic 2,2-dimethylpyranocoumarins with antibacterial activity
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A new efficient synthetic approach to the natural coumarins 5-hydroxyseselin (5), 5-methoxyseselin (3), and (±) cis-grandmarin (9) is described as well as the synthesis of some new derivatives in the 5-methoxyseselin series (10-15). The natural coumarins 7-hydroxyalloxanthyletin (6), alloxanthoxyletin (8), and dipetalolactone (7) have also been obtained as secondary products. The type of fusion of the pyrano ring in all cases has been established by 2D NMR spectroscopy. The compounds have been studied for their in vitro antibacterial activity, which has been compared with that of some previously synthesized seselin derivatives. The most active compounds were 3, 7, 8, 11, and 14. Some structure-activity relationships are discussed.
- Melliou, Eleni,Magiatis, Prokopios,Mitaku, Sofia,Skaltsounis, Alexios-Leandros,Chinou, Efrosini,Chinou, Ioanna
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- SYNTHESIS OF (+/-)-5-HYDROXYMARMESIN: BIOGENETIC PRECURSOR OF THE SKIN PHOTOSENSITIZING AGENT BERGAPTEN
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The synthesis of (+/-)-5-hydroxymarmesin is described.The 5,7-diacetoxycoumarin was selectively C(8) isoprenylated, the isoprenylated intermediate underwent oxidative cyclization to (+/-)-5-hydroxycolumbianetin, which was transformed into (+/-)-5-hydroxymarmesin by alkali treatment.Preliminary experiments showed that this compound has a biogenetic role in the biogenesis of the skin photosensitizing agent bergapten (5-MOP).
- Rodighiero, Paolo,Guiotto, Adriano,Pastorini, Giovanni,Manzini, Paolo,Dall'Acqua, Francesco,et al.
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p. 167 - 172
(2007/10/02)
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