Synthesis of 4-phenylcoumarins from Dalbergia volubilis and Exostema caribaeum
TL;DR: Two isomeric 4-phenyl coumarins, 3′,7-dihydroxy-4′,5-dimethoxy-4]-phenylcoumarin seshadrin from Dalbergia volubilis, and 3'',5]-dimethyl-4'',7]-dimethyltimethoxy 4'',4''-4´,7'' coumarin from Exostema caribaeum have been synthesized.
About: This article is published in Phytochemistry.The article was published on 1991-01-01. It has received 19 citations till now. The article focuses on the topics: Dalbergia.
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TL;DR: A review of 5,7-dihydroxycoumarins can be found in this paper with an emphasis on recent works, including the Horner-Wadsworth-Emmons reaction.
Abstract: The chemical equivalence of the hydroxy groups in the 5,7-dihydroxycoumarin core has challenged synthetic chemists to develop short and efficient strategies for the selective modification of one of the hydroxy groups leaving the second intact. Over the past 100 years, chemists have proposed various approaches to distinguishing between these two groups according to their reactivity. While the early syntheses included simple nonselective reactions of both hydroxy groups and the subsequent separation of mixtures of the 5-O- and 7-O-isomers formed, recent sophisticated approaches often include the introduction of protective groups for selective directing reactions or the completely controlled construction of the 5,7-dihydroxycoumarin framework by Horner–Wadsworth–Emmons reaction. This review discusses in detail approaches towards unsymmetrically substituted 5,7-dihydroxycoumarins as well as factors influencing 5-O vs. 7-O regioselectivity of reactions of 5,7-dihydroxycoumarins. This review covers all the literature since 1921 with an emphasis on recent works. This critical review may facilitate the synthesis of new drug candidates as well as the total synthesis of natural products. 1 Introduction 2 O-Modification of 5,7-Dihydroxycoumarins 2.1 Alkylation/Alkenylation 2.2 Acylation 2.3 Sulfonylation 2.4 Silylation 2.5 Acylation Followed by Alkylation 3 Other Approaches 3.1 Synthesis from Substituted Phloroglucinol 3.2 Synthesis from Derivatives of 2-Acylphloroglucinol 4 Conclusion
2 citations
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TL;DR: Pestaloketide A (1) is an unusual polyketide, featuring a rare 5/10/5-fused ring system as discussed by the authors , with IC50 values ranging from 22.1 to 100 μM.
Abstract: Five undescribed polyketide derivatives, pestaloketides A–E (1–5), along with eleven known analogues (6–16), were isolated from the sponge-derived fungus Pestalotiopsis sp. Their structures, including absolute configurations, were elucidated by analyses of NMR spectroscopic HRESIMS data and electronic circular dichroism (ECD) calculations. Compounds 5, 6, 9, and 14 exhibited weak cytotoxicities against four human cancer cell lines, with IC50 values ranging from 22.1 to 100 μM. Pestaloketide A (1) is an unusual polyketide, featuring a rare 5/10/5-fused ring system. Pestaloketides A (1) and B (2) exhibited moderately inhibited LPS-induced NO production activity, with IC50 values of 23.6 and 14.5 μM, respectively, without cytotoxicity observed. Preliminary bioactivity evaluations and molecular docking analysis indicated that pestaloketides A (1) and B (2) had the potential to be developed into anti-inflammatory activity drug leads.
1 citations
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27 Sep 2006
TL;DR: In this paper, compounds useful for the treatment of various metabolic disorders, such as insulin resistance syndrome, diabetes, hyperlipidemia, fatty liver disease, cachexia, obesity, atherosclerosis and arteriosclerosis, are disclosed.
Abstract: Compounds useful for the treatment of various metabolic disorders, such as insulin resistance syndrome, diabetes, hyperlipidemia, fatty liver disease, cachexia, obesity, atherosclerosis and arteriosclerosis, are disclosed.
References
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TL;DR: In this article, 8-(γ,γ-dimethyl-allyl)-1-Methoxycoumestrol has been isolated from the roots of Lotus creticus along with some known compounds.
16 citations
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TL;DR: The structure of exostemin, a constituent isolated from the benzene extract of the Mexican plant Exostemma caribaeum (Rubiaceae), has been established as 8-hydroxy-5,7-dimethoxy-4-(p -methoxyphenyl) coumarin (I).
14 citations